Tillering Factors for Hybrid Rice

Loss Adjustment Policy & Procedure 

Support for the Rice Blanket Purchase 

Agreement

Final Research Report: Tillering Factors 

for Hybrid Rice

Contract Number D16PA00006

Order Number D16PB00137

Submitted to:

United States Department of Agriculture

Risk Management Agency

Product Administration and Standards Division

Submitted by:

Watts and Associates, Inc.

4331 Hillcrest Road

Billings, Montana 59101

twatts@wattsandassociates.com

DUNS # 112960633

Watts and Associates, Inc., as a Contractor, has developed this material under contract with the United States Department of 

Agriculture and has exclusive ownership rights in part or all of its format and content. No material presented in any format, 

including orally, in print, or electronically, or that has been viewed, disseminated, or heard, may be further disseminated to 

any unauthorized person or entity. “Unauthorized person or entity” may include, but is not necessarily restricted to, any 

person who or entity that has no official connection to this project under the Federal government, or has not been authorized

by Watts and Associates, Inc. to review a portion or all of this material. This material is protected by law.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data i Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Table of Contents

I. Executive Summary ...........................................................................................................................1

II. Background .......................................................................................................................................3

III. Rice Loss Adjustment Standards..................................................................................................13

IV. Data Collection..............................................................................................................................19

V. Components Affecting Rice Yields...............................................................................................20

VI. Rice Tillering.................................................................................................................................23

VII. Discussion and Conclusions........................................................................................................26

VIII. Recommendations ......................................................................................................................28

IX. Impact Analysis.............................................................................................................................30

List of Tables

Table 1. Length to Width Ratios of Rough, Brown, and Milled Long, Medium, 

and Short Grain Rice Required by USDA Grain Standards................................................6

Table 2. Economic Significance of Rice in the Major U.S. Producing States in 2012 

as Compared to All U.S. Agricultural Production ...............................................................9

Table 3. Experience for Rice Crop Insurance in the Major Production States................................12

Table 4. Steps Involved in Performing an Appraisal of Acreage of Rice and 

Other Small Grains and the Output of Each Step ..............................................................13

Table 5. Descriptions of the Stage of Loss and Number of Determined Acres, 

Rice, 2003-2014 ...................................................................................................................16

List of Appendices

Appendix A. Representative Recommended Rice Varieties and Varieties under Investigation in 

the United States

Appendix B. Frequency of Rice Tillering as Documented in Representative Academic 

Literature

List of Attachments

Attachment I. Rice Loss Adjustment Standards Handbook (FCIC-25410-2 (11-2013)) (by 

reference)
Tillering Factors for Hybrid Rice

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I. EXECUTIVE SUMMARY

This report was produced under a contract for the United States Department of Agriculture 

(USDA) Risk Management Agency (RMA). It provides an evaluation of the “tiller factor” used 

in crop insurance loss adjustment for early season losses for a rice crop insured under the Federal 

Crop Insurance Corporation (FCIC) Rice Crop Provisions (11-0018). The Contractor gathered 

information for the report from a variety of sources including published RMA documents, 

published and unpublished RMA data, discussions with rice crop experts, and publications from 

authoritative academic sources relevant to the economic and agricultural characteristics of the 

rice industry. The telephonic and digital discussions with experts involved primarily individuals

whose work focuses on rice breeding and commercial production of rice.

Coverage under the Rice Crop Provisions offers insurance under plan codes 01, 02, and 03 (yield 

protection, revenue protection, and revenue protection with harvest price exclusion, 

respectively).

1

 The insured liability under those provisions for the 2015 crop year was just over

$1.4 billion, while the area insured under those policies was over 2.6 million acres.

2

Tillers are branches that form from the primary stem of the plant. The current appraisal process 

for rice losses that occur when tillering is incomplete uses the tiller factor to estimate the number 

of “live plants” that will exist per acre after tillering is complete. The current tiller factor for rice 

crop insurance loss adjustment was developed prior to 1998. Information documenting the 

process used to develop the factor at that time is no longer available. According to the 

solicitation for the first Task Order, “The crop insurance industry pointed out to RMA that the 

tillering factor currently used while performing rice appraisals is based on conventional rice 

varieties only.”3 If it can be documented that tillering of different rice varieties following a loss 

event are very different, the use of a single tiller factor in appraisals for early season losses is 

called into question.

For loss adjustment, the estimate of live plants that will exist per acre after tillering is complete is 

based on the average number of surviving plants at the time of the appraisal in samples taken 

from the affected field. The estimated number of live plants after tillering is used in the appraisal 

to calculate an estimate of the pounds of rice that could be produced if the crop were maintained. 

Since details of actual appraisals using these procedures are documented primarily in the 

insured’s policy file, the exact portion of the insurance affected by use of the tiller factor for rice 

cannot be established. However, based on the dates of the first cause of loss documented in 

RMA unpublished data, only a small fraction of the insurance could have been affected by 

appraisals before tillering was completed.4

The process of tillering in rice is by no means consistent, especially when the population of live 

plants in a field is reduced. This inconsistency is influenced by a wide range of circumstances. 

Different varieties of rice have different tillering potential, although this potential is rarely 

realized and the number of tillers per plant within a variety is highly variable. Planting density 

 

1 Other rice crop insurance is available under area yield and area revenue policies and the Whole Farm Revenue Protection plan.

2

 USDA, RMA, 2016, RMA Summary of Business Report Generator, 

http://prodwebnlb.rma.usda.gov/apps/SummaryofBusiness/ReportGenerator, accessed April 2016.

3 USDA, RMA, 2016. Solicitation for Rice Loss BPA (Loss Adjustment Policy & Procedure Support for the Rice BPA, 

Statement of Work: Tillering Factors for Hybrid Rice, page 2 of 5.

4 USDA, RMA, 2016, unpublished Type P21 and P11 data for the 2014 crop year.
Tillering Factors for Hybrid Rice

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and planting procedures affect the number of tillers that actually develop in a field. The soil type 

affects the number of tillers that develop per plant. The timing of a loss event impacts the 

number of tillers that can be produced; the number of tillers is also influenced by the health of 

the surviving plant. Furthermore, not all tillers produce panicles. These panicles are clusters of 

flowers. While most of the flowers will eventually form grains of rice, the percentage that do so 

can in turn be affected by numerous circumstances. Generally secondary tillers are more likely 

to form when the plant population is smaller, but are less productive than primary tillers.

For all these reasons, the Contractor found no basis to establish a tiller factor or any set of tiller 

factors appropriate for adjusting early season losses insured under the FCIC Rice Crop 

Provisions. Furthermore, consistent with this observation, the Contractor concludes that there is 

no evidence a set of unique rice tiller factors for different varieties and/or types would have an

appropriate predictive value for the yields that would be obtained under loss scenarios affecting 

these different varieties and/or types.

Based on the wide range of factors that affect tillering, an extremely (and likely exceedingly)

large number of permutations and combinations of conditions would need to be evaluated in any 

field trials to establish additional tiller factors for particular scenarios. There is no evidence 

these costly and time-consuming efforts would produce appropriate tiller factor values for 

adjusting early season losses insured under the FCIC Rice Crop Provisions.

Inasmuch as the Contractor could identify no biological or agronomic basis for establishing a 

different tiller factor, for all rice, for rice by types (including inbred and hybrid rice varieties), or 

for regions, the Contractor recommends an alternative to the tiller factor procedures be 

developed for appraisal of early season losses in rice, including for appraisals focused on replant 

payments. One such alternative would be to require the insured to maintain the crop until an 

appraisal can be completed following tillering or perhaps even following heading. This approach 

would address the impact of plant density on yield, the potentially variations in tillering among 

different rice varieties, the impact of management practices on tillering, and the fact the timing 

of a loss event will impact the number of tillers that can be produced. However, it could create 

substantial problems with authorizing replant in a timely manner. Another alternative would be 

to develop a direct surviving-plant (stand density) to yield factor that eliminates the intervening 

calculations used in the current early-season-loss appraisal procedures. 

Either of these approaches would require substantial additional efforts for implementation. The 

first approach would likely impose substantial burdens on RMA, AIPs, and insureds while the 

second approach may be fraught with some of the same challenges inherent in the current earlyseason-loss appraisal procedures. There may be other alternatives that better address loss 

adjustment for early season losses insured under the FCIC Rice Crop Provisions. A specific 

recommendation regarding the most appropriate alternative to the existing approach would 

require substantial added research beyond the scope of this Task Order. 

The Contractor emphasizes that the findings reported in this document are specific to rice. 

Although the tiller factor method is a part of the loss adjustment process for early season losses 

in other cereal grains, the Contractor makes no findings with respect to the method for those 

crops.
Tillering Factors for Hybrid Rice

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contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

II. BACKGROUND

This section of the report provides background information to assist readers in their assessment 

of the Contractor’s recommendations. This contextual information includes an overview of the 

Blanket Purchase Agreement (BPA) and Task Order (TO) under which the study was conducted; 

details concerning the specific task order directing the research leading to the Contractor’s 

recommendations regarding tiller factors for hybrid rice; an introduction to rice biology and 

agronomics; an overview of the role of crop insurance for rice in the United States; and a general 

summary of crop insurance loss adjustment procedures. The report then continues with sections 

discussing rice yield components, tillering in rice (with a focus on tillering in commercial 

varieties), risks affecting rice production in the United States, specific rice crop insurance loss 

adjustment procedures and experience affected by the tiller factor, and the Contractor’s 

recommendations regarding “the appropriate tillering factor(s) for conventional and hybrid rice 

varieties, which are used while performing rice appraisals.”

5

The Contract

The United States Department of Agriculture (USDA) Risk Management Agency (RMA) issued 

a solicitation (D16PS00016) for proposals addressing research on crop insurance loss adjustment 

procedures for rice. Contracting for this research effort is managed by the Department of Interior 

(DOI) Acquisition Services Directorate. The Acquisition Services Directorate issued a Blanket 

Purchase Order (BPA) to the Contractor under Contract Number D16PA00006 providing for 

research responsive to the solicitation. The Statement of Work (SOW) for the BPA solicitation 

outlines the potential work under the contract as follows:

2.2 Objective:

The objective of this contract is to establish a Blanket Purchase Agreement 

relevant (BPA) in support of loss adjustment procedures utilized for Rice. This 

effort will involve several phases that will be accomplished via orders issued 

under the BPA. The potential tasks are outlined in paragraph 2.4.

2.3 Scope:

This Statement of Work (SOW) provides the framework for the research, analysis, 

and support necessary for the RMA-issued loss adjustment procedures.

2.4 Specific Tasks and Work Requirements:

Task orders may be issued to obtain the following services/deliverables in regard 

to the Rice Loss Adjustment Standards Handbook.

RMA considers the following components necessary.

2.4.1 Research for Loss Adjustment Procedures:

The government may task the contractor with conducting data gathering of the 

current risks and issues that the producers face with the loss of their specific 

crop(s).

 

5 USDA, RMA, 2016. Solicitation for Rice Loss BPA (Loss Adjustment Policy & Procedure Support for the Rice BPA), 

Statement of Work: Tillering Factors for Hybrid Rice, page 2 of 5.
Tillering Factors for Hybrid Rice

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contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

2.4.2 Appraisal Methodologies:

The government may task the contractor with researching and developing crop 

specific appraisal methodologies for potential production. This may involve 

development of appraisal tillering factors, determining and recommending 

appropriate test weight pack factors, etc. The contractor may develop new, and 

update current, appraisal methodologies after conducting necessary research on 

the most appropriate methodology for rice.

2.4.4 Rice Tillering Factors:

6

The government may task the contractor with researching, updating and 

establishing tillering factors for appraisals of hybrid rice varieties versus 

conventional rice varieties.

2.4.5 Serve as a Resource to Address Industry or Expert Review Comments

Regarding Loss Adjustment Policies and Procedures:

The Government may task the Contractor to aid RMA in responses to any industry 

comments or expert reviewers...

7

The focus of the BPA is on elements of procedures used in adjusting for crop insurance losses, 

especially where the production is not anticipated to be maintained and where replanting may be 

required. The SOW for the solicitation for the first TO under the BPA Contract, which served as 

the basis for the Contractor’s proposal focused on this report, calls for a study of the tiller factor,

which is used in the adjustment procedures for crop losses that occur early in the growing 

season. Additional consulting activities related to loss adjustment for rice crop insurance may be 

required under optional task orders. Language from the SOW for the solicitation regarding the 

first TO states:

2.1 Objective:

The objective of this [Task Order] is to conduct research and determine the 

appropriate tillering factor(s) for conventional and hybrid rice varieties, which 

are used while performing rice appraisals...

2.4 Specific Tasks:

2.4.1 Draft Research Report and Teleconference:

The contractor shall review and analyze the Rice LASH to demonstrate 

understanding of the appraisal methods including the following specific 

procedures that apply a tillering factor during the appraisal process.

The contractor shall accomplish the following tasks:

• Gather information from crop insurance industry representatives, rice and 

hybrid rice producers, researchers, rice grower associations, seed 

manufacturers, rice research publications, and any other sources that will 

enable fulfillment of this contract through telephone, email, etc. These 

 

6 The break in numbering (i.e., the absence of a point 2.4.3) displayed here is faithfully reproduced from the contract materials.

7 USDA, RMA, 2016. Solicitation for Rice Loss BPA and Order 1 (D16PS00016), Loss Adjustment Policy & Procedure 

Support for the Rice BPA, pages 7-8 of 12.
Tillering Factors for Hybrid Rice

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sources shall offer reliable knowledge and information regarding rice 

production as it relates to the Rice LASH.

• Determine if the tillering factor utilized for conventional rice and hybrid 

rice should be different.

• Provide the states in which rice, and hybrid rice, is grown.

• Determine if it would be best to establish tillering factors on a national 

basis, as currently done, or if it should be done on a different basis (such 

as regional basis).

• Determine if additional tillering factors should be established by region or 

state that are more appropriately based on the different rice 

characteristics such as varieties, yields, practices. etc. When adjusting a 

loss insured under the federal crop insurance program administered by 

the United States Department of Agriculture (USDA) Risk Management 

Agency (RMA), it is desirable to maintain the crop until production to 

count can be based on actual grain harvested. However, because of the 

extent of damage causing the loss, make the cost of circumstances [of] 

maintaining the crop unwarranted. Under these circumstances, the 

additional potential production inherent in the remaining plants must be 

estimated by an appraisal.8

In response to the requirements of this SOW, the Contractor conducted an extensive examination

of the literature regarding conventional and hybrid rice varieties with a special focus on tillering 

and the tiller factor. A report of the research findings follows.

Rice

Rice is the common name for the wide range of species of perennials in the genus Oryza. The 

genus is in the grass family (Poaceae, formerly called Gramineae) and includes two important 

agricultural species: Oryza sativa (Asian rice) and Oryza glaberrima (African rice). Both 

species grow in tropical and warm temperate environments.

Rice is a significant source of food in many cultures, especially in Africa and Asia. While 

cultivated rice plants can grow two to eight feet in height, commercial varieties in the United 

States tend to be three to four feet tall.9 Cultivated rice plants grown in the United States 

generally mature in less than 150 days, with some commercial varieties maturing in about two

thirds that time (depending on variety, location, cultural practices, and weather).10 An additional 

period, whose length is influenced primarily by weather, may be required for dry-down.

O. glaberrima was historically a substantial food source in sub-Saharan Africa. African rice was 

cultivated in the United States during colonial times. O. sativa is widely grown outside Africa 

and is now replacing O. glaberrima in much of the commercial production on the African 

 

8 USDA RMA 2016, Loss Adjustment Policy & Procedure Support for the Rice BPA, Statement of Work, Task Order #1: 

Tillering Factors for Rice, page 3 of 5.

9 Louisiana State University Agricultural Center, 2015, Rice Varieties and Management Tips 2015, 

http://www.lsuagcenter.com/articles/connected/rice-varieties-and-management-tip, accessed March 2016.

10 Global Rice Science Partnership, 2016, Ricepedia: Growth Phases, http://ricepedia.org/rice-as-a-plant/growth-phases, accessed 

March 2016. 
Tillering Factors for Hybrid Rice

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continent.

11

 U.S. production of rice is now almost exclusively of Asian rice,12 including long, 

medium, and short grain types.

13

 These rice grain length types are defined by the USDA Federal 

Grain Inspection Service (FGIS) in the Rice Inspection Handbook. FGIS allows the type 

determinations to be made by “cursory examination” of the sample being inspected unless there 

is a need for an objective determination. “When a detailed examination [of type] is necessary,

[inspectors] measure the length and width of 15 unbroken kernels taken at random from the work 

sample and determine their average length-width ratio.”14 Since the hull and bran contribute 

disproportionately to length as compared to their contribution to width, FGIS has established

slightly different length to width ratio standards for rough rice,15 brown rice,

16 and milled rice17

(Table 1).

Table 1. Length to Width Ratios of Rough, Brown, and Milled Long, Medium, and Short 

Grain Rice Required by USDA Grain Standards

Rough Rice1

Long 3.4 to 1 and more

Medium 2.3 to 3.3 to 1

Short 2.2 to 1 and less

Brown Rice2

Long 3.1 to 1 and more

Medium 2.1 to 3.0 to 1

Short 2.0 to 1 and less

Milled Rice3

Long 3.0 to 1 and more

Medium 2.0 to 2.9 to 1

Short 1.9 to 1 and less

1 USDA, FGIS, 2014, Rice Inspection Handbook, Chapter 3, page 3-6.

2 USDA, FGIS, 2014, Rice Inspection Handbook, Chapter 4, page 4-6.

3 USDA, FGIS, 2014, Rice Inspection Handbook, Chapter 5, page 5-6.

Like most grasses grown as crop plants (as opposed to those grown grass species for horticultural

uses) rice is grown for its fruit. The fruit are derived from small wind-pollinated flowers borne 

on a branched18 arching to pendulous inflorescence 12 to 20 inches long. The technical name for 

this type of inflorescence is a panicle. In the literature, the term panicle is frequently used for the 

structure bearing the fruits of the rice plants. The fruit is a caryopsis, the typical fruit of 

grasses.

19

 The entire fruit (rough rice) can be used for feed. The portions of the fruit that cannot 

be digested by humans are removed by milling to produce the rice used as a food (brown and 

milled rice).

 

11 Linares, O.F., 2007, African rice (Oryza glaberrima): History and future potential, Proceedings of the National Academy of 

Sciences, 99: 16,360–16,365, http://www.pnas.org/content/99/25/16360.full, accessed April 2016.

12 O. glaberrima is grown in the United States primarily as the subject of academic research projects.

13 USDA FGIS uses the term “type” when characterizing the ratio of length to width of the rice fruits and/or seeds. The FGIS 

uses the term “class” when characterizing these ratios and describing the extent of breakage and contamination by other types.. 

14 USDA, FGIS, 2014, Rice Inspection Handbook, pages 3-6, 4-6, and 5-6 for rough (paddy), brown (hulled), and milled rice, 

respectively.

15 Also called paddy rice, this is rice with the hulls intact.

16 Rice whose hulls have been removed but whose bran is still intact.

17 Rice whose hulls and bran have been removed.

18 The branches of the panicle are called spikelets.

19 Caryopses are commonly called grains, although the term is more ambiguous since it can refer to the fruit, the seed, or the plant 

producing the fruit.
Tillering Factors for Hybrid Rice

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The key difference between rice and other grain crops is that rice grows readily in standing water 

or in very wet soil. While rice is a perennial with the potential to produce a harvestable crop in 

the first and ensuing years, in most developed countries including the United States, rice is 

grown as an annual. This management approach increases the average annual yield and reduces 

the yield variability from year to year.

Both inbred and hybrid varieties of O. sativa are planted in the United States. The predominate 

rice varieties grown in the southern states in the United States are long-grain varieties. In these 

states much of the crop is grown from hybrid seed. In contrast, medium-grain varieties 

predominate in California fields, where a substantial portion of the crop is still grown from 

inbred seed.20 Short grain rice is primarily produced in California. Most states have production 

of limited quantities of specialty rice appropriate for the locale.

Almost all U.S. rice production is irrigated. The traditional method for cultivating rice is 

flooding the fields while, or after, setting the seed. This method requires careful planning and 

careful servicing of the dykes and channels. There is ongoing and promising research into the 

potential for and implications of sprinkler irrigated rice. While flooding is not an absolute 

requirement, other methods of irrigation require more weed and pest control.

Hybrid Rice

Like most wind-pollinated species, self-fertilization is common in rice. Historically, rice 

varieties were inbred because of this self-fertile attribute. After the discovery of O. sativa plants 

with abortive pollen, breeders developed cytoplasmic male sterile (CMS) lines. These lines are 

bred with maintainer lines (lines that produce the next generation of CMS seed) and separately 

with fertility-restorer lines for the production of commercial seed. For production of seed for 

commercial planting, the CMS line is the female parent and the fertility-restorer lines are the 

male parent. Since three different lines are required for production of commercial quantities of 

these rice seeds, these hybrids are called “three-line hybrids.”

Grain quality and yield limitations affected the adoption of three-line hybrid rice commercially. 

The yield limitations of the three-line hybrid varieties are most likely tied to the genetics of the 

CMS parent. Breeders have overcome some of these limitations and in the United States there 

has been commercial production of some three-line hybrid varieties, particularly in regions 

where improved yield and quality have been demonstrated.21

In recent years, breeders have developed new-generation hybrid rice varieties that often have a 

substantial yield advantage over the inbred varieties.22 Many of these are produced as hybrids 

from just two-lines. Two-line rice hybridization systems do not require a maintainer line. Under 

specific photoperiods one line (used as the female line in the hybridization) is male sterile; but 

 

20 Global Rice Science Partnership, Research Program on Rice, 2013, Rice Almanac, Fourth Edition, page 98, 

http://books.irri.org/9789712203008_content.pdf, accessed March 2016.

21

 Tran, D.V., and V.N. Nguyen, UN FAO, 1998, International Rice Commission Newsletter, Global hybrid rice: progress, issues 

and challenges, http://www.fao.org/docrep/003/w8595t/w8595t03.htm#TopOfPage, accessed November 2015.

22 Louisiana State University Agricultural Center, 2015, Rice Varieties and Management Tips 2015, 

http://www.lsuagcenter.com/articles/connected/rice-varieties-and-management-tip, accessed March 2016.
Tillering Factors for Hybrid Rice

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contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

sterility of this parent can be controlled by day length. Under appropriate photoperiods this line 

is self-fertile and is consequently self-maintaining.23

Research and development on two-line hybrid rice has focused on greater yields and superior 

grain quality to those of the three-line hybrids. The two-line hybrid plants tend to be more robust 

than three-line hybrid plants and the grains produced by the two-line hybrid plants are less 

fragile than the grains produced by a majority of three-line plants. Consequently, both seed and 

commercial production of two-line hybrids generally result in greater yields than those of threeline hybrid rice varieties.24

Economic Significance of Rice

Rice plays a major role as an agricultural commodity globally, with rice harvested from 208

million of the world’s 721 million harvested grain acres in 2014. Only wheat and corn have a 

larger share of the global harvested grain acres.25 Overall, the United States exports about half of 

its rice crop,26 with 3.5 million tons (3.2 million metric tonnes) of the world’s approximately 44 

million tons (40 million metric tonnes) of internationally-traded rice exported from the United 

States in 2013.

27,28

 Most U.S. rice exports are of the long-grain varieties and of combined 

medium and short-grain products. Exports to Mexico and Central America are mostly of rough 

(unmilled) rice. Exports to northeast Asia, Canada, the Caribbean, the European Union, the 

Middle East, and Sub-Saharan Africa are primarily of milled rice. A small portion of the rice 

exported from the United States is of highly processed (parboiled, etc.) rice. These highly 

processed rice products are exported primarily to developed countries.29

Comprehensive agronomic data for the United States are collected by the USDA National 

Agricultural Statistical Service (NASS) every five years for publication in a Census of 

Agriculture. This data collection and its analysis provide the “only source of uniform, 

comprehensive agricultural data for every state and county in the United States.”

30 Every farmer 

and rancher, regardless of the size or type of operation, is expected to participate in the census 

data collection processes. The last Census of Agriculture data collection occurred for the 2012 

crop year. The economic significance of rice production in the United States in 2012, as 

documented by the Census, is summarized in Table 2. Rice production in 6 principal states 

accounts for more than 99 percent of the total rice value nationally. The remaining rice produced 

in the United States that year was grown in Florida (14 farms), Illinois (1 farm), South Carolina 

(1 farm), and Tennessee (6 farms).31 According to NASS estimates for the 2015 crop year, rice 

production in the United States was valued at $2.6 billion.32

 

23 However, the seed resulting from the propagation of these self-maintaining lines produced when the plants are self-fertile are 

inbred. Consequently the self-maintaining lines are used as both female parent plants for hybridization and both parents in the 

production of the next generation of these female parent plants.

24

 Ibid.

25

 UN FAO, 2014, FAOSTATS, http://faostat3.fao.org/compare/E, accessed March 2016.

26

 USDA, ERS, 2015, Rice, http://www.ers.usda.gov/topics/crops/rice/trade.aspx, accessed November 2015.

27 The most recent year for which data are available.

28

 UN FAO, 2016, FAOSTATS, http://faostat3.fao.org/browse/T/TP/E, accessed March 2016.

29

 USDA, ERS, 2015, Rice, http://www.ers.usda.gov/topics/crops/rice/trade.aspx, accessed November 2015.

30 USDA, NASS, Census of Agriculture, 2015, About the Census, https://www.agcensus.usda.gov/About_the_Census/, accessed 

November 2015.

31 USDA, NASS 2012 Census of Agriculture, state level data accessed through Quick Stats.

32 USDA, NASS, 2015, Quick Stats https://quickstats.nass.usda.gov/results/D635F46F-3758-34A8-9C2B-30039EB26A5C, 

accessed April 2016.
Tillering Factors for Hybrid Rice

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Table 2. Economic Significance of Rice in the Major U.S. Producing States in 2012 as 

Compared to All U.S. Agricultural Production

States with 

Significant Rice 

Production

All Farms and Cropland

Number of 

Farms

Total Land in

Farms

Agricultural 

Production ($)

Arkansas 45,071 13,810,786 9,775,758,000

California 77,857 25,569,001 42,627,472,000

Louisiana 28,093 7,900,864 3,809,401,000

Mississippi 38,076 10,931,080 6,441,025,000

Missouri 99,171 28,266,137 9,164,886,000

Texas 248,809 130,153,438 25,375,581,000

Rice

Arkansas 2,345 1,291,000 1,314,526,000

California 1,391 562,000 782,644,000

Louisiana 822 402,000 363,783,000

Mississippi 259 130,000 131,278,000

Missouri 385 180,000 151,731,000

Texas 361 135,000 136,187,000

Source: After USDA-NASS 2012 Census of Agriculture, state level data accessed through Quick Stats except 

for planted acreage which is from USDA-NASS 2012 survey data accessed through Quick Stats.

The rice grown in the four states with very limited production is destined for local and specialty 

markets.33 Most rice grown in Florida is produced in Palm Beach and Hendry Counties in the 

Everglades Agricultural Area Environmental Protection District (EAA). Due to the long 

growing season in these counties, rice can be harvested twice with the second ratoon crop 

producing a somewhat lower yield than the initial harvest. The rich organic soils where the 

Florida crop is grown raise the rice protein levels for both those harvests as compared to the 

levels of protein in rice harvested in other states. The Florida rice crops provide substantial 

amounts of biomass to the fields, which improves both soil tilth and drainage. The improved 

soils can result in higher sugarcane yields.34

Rice has been grown in Arkansas, Louisiana, and Texas since the mid-19th Century. Commercial 

rice production in California began in the early 20th Century. In recent years, U.S. rice 

production has increased, especially in Arkansas, Mississippi, and Missouri. Nonetheless, 

California now produces the second-largest rice crop in the United States after Arkansas. While 

more than 100 varieties of rice are grown world-wide, approximately 20 are produced 

commercially in the United States in any given year. Varieties produced in all regions change 

from year to year as better seed is developed (See Appendix A).

35

 

33 Agrilicious SPC, 2016, Local Rice in Tennessee, http://www.agrilicious.org/local/rice/tennessee, accessed April 2016; 

Carolina Plantation, 2014, The only colonial plantation to still offer rice in the Carolinas, 

http://www.carolinaplantationrice.com/index/, accessed April 2016.

34 Palm Beach County, 2016, General Information Rice, 

http://www.pbcgov.com/coextension/agriculture/sugarcane/information/rice.htm, accessed April 2016.

35 USDA, ERS, 2015, Rice, http://www.ers.usda.gov/topics/crops/rice/trade.aspx, accessed November 2015; Louisiana State 

University Agricultural Center, 2014, Rice Varieties and Management Tips 2014, 

http://www.lsuagcenter.com/NR/rdonlyres/97DE9091-DFAE-46AD-846A63B1B12512FB/94855/pub2270RiceVarieties2014.pdf, accessed March 2016.; Louisiana State University Agricultural 

Center, 2015, Rice Varieties and Management Tips 2015, 

http://www.lsuagcenter.com/~/media/system/8/6/4/0/864051f436294bf5e337d225dc5aad81/pub2270ricevarieties2015final.pdf, 

accessed March 2016..
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 10 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Loss Adjustment

“Loss adjustment” is the process for establishing the appropriate indemnity payment to address 

an insured loss. The USDA RMA Loss Adjustment Manual (LAM) Standards Handbook 

(25010-1H) “identifies loss adjustment standards and requirements for determining production or 

revenue and adjusting crop insurance claims in a uniform and timely manner.”36 The LAM 

documents general requirements for loss adjustment and for completing policy-related 

inspections (including appraisals). The Rice LASH (Attachment I, found at 

http://www.rma.usda.gov/handbooks/25000/2014/14_25410-2h.pdf) includes specific crop 

appraisal methods, claims completion instructions, and form standards, and supplement the 

standards identified in the LAM. The Rice LASH details specific standards for adjusting losses 

for rice.37 All Approved Insurance Providers (AIPs) use these Rice LASH standards for both 

loss adjustment and loss adjustment training.

The tiller factor plays a role in rice appraisals for loss adjustment made before heading while 

tillering is not yet complete (tillering incomplete). The tiller factor is multiplied by a count of 

viable plants in a sample to establish the potential number of plant seed heads (and eventually of 

grains) likely to develop if the crop were appropriately maintained. Inasmuch as the tiller factor 

is used in the calculations to estimate potential production when the crop has been damaged prior 

to producing tillers, if the tiller factor is too small, the appraised production to count for early 

season losses is under-estimated. Under these circumstances, any indemnity based on the 

appraised production to count will be too large. Furthermore, the tiller factor is used in assessing 

the potential production in a damaged field to determine if a replanting payment should be made. 

If the tiller factor is too small, replanting payments will be made when they are not justified. 

Conversely, if the tiller factor is too large and an early season loss occurs, the apprised 

production to count is over-estimated and the amount of any indemnity will too small. 

Moreover, under these circumstances a replanting payment that is justified by the biological 

condition of the crop may be withheld. A detailed analysis of the Rice LASH is provided in a 

separate section of this report.

Rice Crop Insurance History

The Agriculture and Consumer Protection Act of 1973 and the Rice Production Act of 1975 

authorized a permanent disaster payment program for rice. The acts provided a system for 

payments in response to a specific disaster without the need for Congressional action. The 

program was reauthorized in the Food and Agriculture Act of 1977. The 1980 Federal Crop 

Insurance Act ended the standing disaster payment program over concerns about its growing cost 

and the performance of the program.38

Under the Federal Crop Insurance Program, both individual and area-based yield and revenue 

crop insurance products are available for rice producers. Nonetheless, historically crop insurance 

participation by rice producers was lower than for other grain crops. This lower participation 

resulted from two factors: historically participation in the entire crop insurance program in the 

 

36 USDA, RMA, 2015, 25000 –Loss Adjustment Standards, http://www.rma.usda.gov/handbooks/25000/index.html, accessed 

November 2015.

37 See for example USDA, RMA, 2013, Rice Loss Adjustment Standards Handbook, 2014 and Succeeding Crop Years, FCIC25410-2 (11-2013), http://www.rma.usda.gov/handbooks/25000/2014/14_25410-2h.pdf, accessed November 2015.

38 The Environmental Working Group, 2016, Crop Insurance: History of Disaster and-Crop-Insurance Programs, 

http://www.ewg.org/research/crop-insurance/history-disaster-and-crop-insurance-programs, accessed March 2016.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 11 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

areas where rice is grown was lower than for other regions; and as an irrigated crop, rice yield 

variability tends to be low. The low yield variability results in infrequent triggering of 

indemnifiable losses.

Nonetheless, participation by rice producers has increased in the past several years and in 2012, 

approximately 80 percent of the NASS Census reported planted acres were insured according the 

RMA’s summary of business. However, the Contractor notes producers insuring rice purchase 

less additional coverage insurance than producers growing other grain crops. Table 3

summarizes the insurance experience for all RMA insurance products for rice in the major riceproducing states over the last ten years.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 12 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Table 3. Experience for Rice Crop Insurance in the Major Production States

Year

All Arkansas Rice Products All California Rice Products

Total 

Liability 

($)

Total 

Premium 

($)

Total 

Indemnity 

($)

Loss 

Ratio

Total 

Liability 

($)

Total 

Premium 

($)

Total 

Indemnity 

($)

Loss 

Ratio

2006 160,355,022 7,824,800 2,443,785 0.312 113,615,071 4,941,231 8,757,732 1.772

2007 187,351,780 9,045,843 1,488,424 0.165 143,654,345 5,799,099 4,029,206 0.695

2008 252,975,793 11,952,179 4,566,027 0.382 161,603,485 5,980,189 936,258 0.157

2009 360,666,504 20,564,298 17,884,218 0.870 281,079,079 11,726,058 2,460,057 0.210

2010 510,497,069 30,395,568 19,528,458 0.642 223,123,008 7,959,709 2,667,144 0.335

2011 448,858,758 27,541,428 62,369,670 2.265 304,408,440 10,395,787 2,409,687 0.232

2012 421,798,241 22,534,525 3,229,333 0.143 282,377,325 9,784,628 1,184,976 0.121

2013 494,091,094 27,242,516 64,069,669 2.352 296,402,931 8,419,394 3,323,878 0.395

2014 668,688,932 37,780,679 33,208,253 0.879 543,828,788 23,408,594 50,485,136 2.157

2015 607,170,218 29,508,750 65,007,040 2.203 434,643,326 15,713,267 55,209,677 3.514

Year

All Louisiana Rice Products All Mississippi Rice Products

Total 

Liability 

($)

Total 

Premium 

($)

Total 

Indemnity 

($)

Loss 

Ratio

Total 

Liability 

($)

Total 

Premium 

($)

Total 

Indemnity 

($)

Loss 

Ratio

2006 64,380,050 3,729,443 6,174,129 1.656 34,772,310 1,578,257 144,494 0.092

2007 79,772,235 4,197,084 796,984 0.190 42,373,126 1,893,718 339,412 0.179

2008 116,016,097 5,830,427 5,454,034 0.935 66,586,714 3,005,900 1,852,220 0.616

2009 163,114,643 9,805,732 10,365,187 1.057 110,342,719 7,538,684 8,410,598 1.116

2010 180,940,611 10,655,699 4,482,836 0.421 151,412,534 9,986,048 5,497,235 0.550

2011 170,989,174 8,251,293 5,308,157 0.643 84,706,019 5,255,197 3,903,146 0.743

2012 162,276,296 7,361,868 2,486,139 0.338 63,104,343 3,440,602 1,097,490 0.319

2013 194,677,788 7,866,863 1,951,903 0.248 83,721,212 5,035,438 9,616,558 1.910

2014 228,857,478 9,911,529 3,435,099 0.347 112,656,462 5,838,775 6,542,350 1.121

2015 179,977,208 6,504,931 7,433,573 1.143 88,450,285 3,438,967 6,452,207 1.876

Year

All Missouri Rice Products All Texas Rice Products

Total 

Liability 

($)

Total 

Premium 

($)

Total 

Indemnity 

($)

Loss 

Ratio

Total 

Liability 

($)

Total 

Premium 

($)

Total 

Indemnity 

($)

Loss 

Ratio

2006 21,925,511 1,632,100 736,375 0.451 38,617,384 1,855,904 1,291,464 0.696

2007 22,670,956 1,673,316 380,139 0.227 48,165,124 2,325,015 1,846,077 0.794

2008 34,739,265 2,557,875 300,361 0.117 66,256,263 3,089,684 2,511,226 0.813

2009 53,430,749 4,400,277 2,061,981 0.469 88,083,878 5,044,994 4,438,131 0.880

2010 67,299,919 5,370,338 950,277 0.177 88,345,782 4,748,967 1,565,694 0.330

2011 60,342,801 5,059,326 13,295,876 2.628 96,085,035 5,212,679 2,725,882 0.523

2012 62,803,913 4,069,538 1,001,995 0.246 101,328,718 7,706,240 32,257,129 4.186

2013 77,905,894 5,294,777 7,846,813 1.482 130,007,098 8,599,958 36,864,930 4.287

2014 94,160,199 6,874,467 4,833,431 0.703 128,872,170 9,571,026 43,612,141 4.557

2015 78,106,300 5,332,955 8,343,679 1.565 113,534,564 8,366,743 44,859,561 5.362

Source: After USDA-RMA, 2015 Summary of Business data accessed through the Summary of Business report Generator website.

There is no pattern of indemnities or loss ratios that suggests a fundamental weakness in the Rice 

Crop Insurance Program. The substantial loss years recently in California and Texas reflect 

years of major droughts and associated impacts on irrigation water availability. In California, 

with its substantial plantings of inbred rice, the loss ratios over time are not substantially 

different from the loss ratios in the southern states other than Texas. Hybrid rice varieties 

predominate in these south central regions. A full evaluation of the rice crop insurance program 

is beyond the scope of the work required under this TO.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 13 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

III. RICE LOSS ADJUSTMENT STANDARDS

This section of the Deliverable responds to the requirement in the SOW which states: “The 

contractor shall review and analyze the Rice LASH [Loss Adjustment Standards Handbook] to 

demonstrate understanding of the appraisal methods including the following [sic] specific 

procedures that apply a tiller factor during the appraisal process”

39

An appraisal is “an estimate or considered opinion.”40 In the context of crop insurance, it is an 

estimate developed from the facts concerning the condition of a crop in a field as determined to 

exist by the loss adjuster. Those facts then are converted into an estimate of the amount of 

production lost by means of parameters that reflect expectations regarding the probable 

development of the crop from its current condition until maturity. The tiller factor is one of 

those parameters. The appraisal process for crops insured under the Small Grains Provisions 

(barley, oats, rye, and wheat) and for rice are performed before tillering is complete is 

summarized in Table 4.

41

Table 4. Steps Involved in Performing an Appraisal of Acreage of Rice and Other Small 

Grains and the Output of Each Step*

Step Output

Determine number of live plants in 10 

feet of row length

The estimated number of plants capable of producing tillers.

Average the number of live plants in all 

sample rows

The average number of plants capable of producing tillers as determined 

from the required number of samples.

42

Multiply average number of live plants 

by the tiller factor

The estimated number of plants that will exist after tillering is complete 

(result from second step multiplied by 2.5 for rice).

Divide estimated number of tillers by the 

square foot factor

The estimated number of tillers per square foot of area. Square foot 

factor is an arithmetic result determined by the row width and the square 

feet in an acre.

Multiply estimated tillers per square foot 

by tiller to pounds yield factor

The estimated number of pounds of grain production per acre. Tiller to 

pounds yield factor differs by type of rice.

Source: USDA, RMA, 2013, Rice Loss Adjustment Standards Handbook ( FCIC-25410-2 (11-2013) and USDA, RMA, 2015, Small Grains Loss 

Adjustment Standards Handbook ( FCIC-25430-2 (06-2015).

* The Contractor notes “tiller” is not defined in the Rice LASH, the LAM or CIH. The Rice LASH use of the term does not differentiate among 

plants originating from the seedling, primary tillers, and secondary tillers as used in the biological and agronomic literature. Consequently, the 

yield potential from each of these sources is assumed to be the same. Biologically, a tiller is a branch that forms from axillary buds on the main 

stem of the plant once that stem has produced four to five leaves. These branches can form differentially depending on a number of causes. 

Some of these branches, especially in the earliest stages of development, have the potential to produce seed.

The number of tillers produced per surviving seed directly affects the potential production of the 

field because that parameter affects the number of panicles (i.e., flowers clusters) and ultimately 

the number of filled grains produced per unit of area (see the discussion on yield in the following 

Section). The estimated weight of the seeds that will be produced per head can be converted to 

total pounds of production per acre.

 

39 USDA, RMA, 2016. Solicitation for Rice Loss BPA (Loss Adjustment Policy & Procedure Support for the Rice BPA, 

Statement of Work: Tillering Factors for Hybrid Rice, page 3 of 5.

40 Houghton Mifflin Harcourt Publishing Company, 2014, The Free Dictionary by Farlex, 

http://www.thefreedictionary.com/appraisal, accessed March 2016.

41 An appraisal may involve both fields where tillering is incomplete and fields where tillering is complete, depending on the 

condition of the field. This discussion focuses solely on the process for fields where tillering is incomplete.

42 The required number of samples is based on field size and uniformity of the surviving stand of rice.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 14 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

The Rice LASH advises the loss adjuster as follows regarding appraisals for damage other than 

hail when tillering is incomplete: “WHENEVER POSSIBLE, delay appraisals when damage 

occurs before tillering is complete and the number of live plants capable of producing rice cannot 

be identified. Use judgment as to the number of tillers that will produce a normal head” (section 

6B(2)(a), emphasis in the original). However, the Contractor notes delay is not always possible. 

When a loss should be indemnified with replanting payments is one situation in which an 

appraisal cannot be delayed until tillering is complete. The determination that acreage qualifies 

for a replanting payment is based on an assessment that the remaining stand in the area where the 

crop is damaged will not produce at least 90 percent of the production guarantee (0.90 x APH 

approved yield x coverage level factor). In general, producers most likely want to replant 

damaged acreage before the final planting date, not wait until the initially planted (damaged) 

acreage produces tillers.

Table 4 shows the tiller factor is one of the two biological parameters that establish an appraised 

amount of production per acre for pre-tillering appraisals. The other biological parameter is the 

tiller to pounds yield factor from Table D in the LASH. The tiller to pounds yield factor 

currently is 120 pounds per acre for all varieties of short and medium grain rice and 105 pounds 

for all varieties of long grain rice.

However, if the appraisal is performed after heading, an average count of kernels per square foot 

to pounds per acre yield factor (Table E) is included in the appraisal process. This factor varies 

significantly by variety within type and is based on the average weight of kernels for the variety. 

While the Contractor does not believe it is reasonable to assess a constant tiller to pounds yield 

factor within type before heading and a yield factor that is variable by variety within type after 

heading, any investigation into the tiller to pounds yield factor or the average kernels per square

foot to pounds per acre yield factor is outside the scope of the SOW.

The Contractor reviewed section 6B(2) (Before Heading Appraisals – Tillering Incomplete) and 

section 8C (Worksheet Entries and Completion Information) Part I (Before Heading) of the Rice 

LASH to evaluate the degree to which the procedures are “... implemented efficiently and do not 

impose unwarranted burdens and costs on producers, AIPs and the government.” The Contractor 

found that sub-sections 6B(2)(b) and (c) are somewhat opaque with respect to the directives to 

the loss adjuster. “Using the tiller factor from TABLE C, convert single plant counts to tillers to 

count” (sub-section 6B(2)(b)). Convert how? By multiplication? By division? By 

exponentiation? Similarly, sub-section 6B(2)(c) instructs the loss adjuster to “convert.” The 

instructions in sub-section 8C are much more comprehensive, providing details regarding the 

numbers to be entered in each cell of the worksheet and the arithmetic processes by which 

subsequent entries are determined. The explanation of the appraisal process may be more 

efficient if the information in sub-sections 6B(2)(b) and (c) were omitted entirely. A simple 

declaration in sub-section 6B(2) that the details regarding the appraisal are to be determined by 

following the process outlined in section 8C would suffice.

The Contractor does not believe these points are sufficient to find that the procedures are not 

“implemented efficiently” and therefore “impose unwarranted burdens and costs.” These are 

merely points of clarification of procedures. The procedures specified in the identified sections 

of the LASH are necessary for the proper administration of the crop insurance program. Early 
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 15 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

season appraisals are a necessary and vital element of the program to enable it to meet the 

diverse conditions that exist in the circumstances of crop production. The need to determine the 

right to a replanting payment is a prime example of the need for early season appraisals. Support 

of a producer’s decision that a damaged crop cannot be economically carried to harvest due to 

the fact that the costs of fertilizer, pesticide, and other inputs as well as of harvest exceed the 

probable revenue to be realized from harvest (i.e., abandonment of the acreage) is another 

example of need for early season appraisals. However, the crop insurance program does need to 

assure that the potential value of any estimated production is recognized prior to payment of an 

indemnity in the event acreage is abandoned. Thus, there is need for early season appraisals.

The before tillering loss adjustment procedure merely asks the loss adjuster to count the number 

of live plants in several different samples that are ten feet in length. The number of samples is a 

function of the number of acres in the field or sub-field: a minimum of three samples for up to 10 

acres, plus one additional sample for each 40 acres or fraction thereof. A sample consists of ten

consecutive linear feet randomly selected from a randomly selected row of the planted crop. 

Determining whether a plant is “live” and capable of producing tillers can be a judgement. The 

Contractor does not believe the requirement constitutes an undue burden given the needs of the 

crop insurance program.

The Contractor also reviewed the instructions in Section 9C of the LASH (Form Entries and 

Completion Information) Section I (Determined Acreage, Appraised Production, and 

Adjustments) item 31 (Appraised Potential). The instructions direct the loss adjuster to enter the 

potential production for acreage appraised as shown on the appraisal worksheet. However, this 

instruction applies only for preliminary and final appraisals for loss of production. For 

replanting payments, the loss adjuster is directed to enter the number of pounds allowed for a 

replanting payment. The degree to which the acreage failed to meet the 90 percent threshold is 

not documented in the numerical data captured on the worksheet. That information is included 

in the Narrative section of the Production Worksheet; however, this treatment does not lend itself 

to analytical support to determine the appropriate amount of a load for replanting at the various 

coverage levels.

The Contractor’s proposal stated that the Deliverable “will review the loss information from the 

RMA Type P21 data to see if it contains data about how tillering is impacting the losses for the 

rice program.” A total of 28,583 Type P21 records were found for the years 2003-2014. These 

records include approximately 3.2 million gross determined acres and $561 million of payments, 

as shown in Table 5.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 16 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Table 5. Descriptions of the Stage of Loss and Number of Determined Acres, Rice, 2003-

2014

Stage Description Determined 

Acres Percent Payments ($) Percent

Acreage not containing DCE or not qualifying for DCE 19,694 0.6% 0.0%

Denied Claim 3,688 0.1% 0.0%

Harvested 775,950 23.9% 95,318,465 17.0%

Harvested Acreage Qualifying for DCE 101,091 3.1% 6,270,589 1.1%

Not Replanted 324 0.0% 0.0%

NULL 1,954 0.1% 40,799 0.0%

Prevented Planting - Unplanted Acreage 931,790 28.7% 113,021,213 20.1%

Prevented Planting - Unplanted Acreage with 10% Buy Up 

Option 818,908 25.3% 265,504,249 47.3%

Prevented Planting - Unplanted Acreage with 5% Buy Up 

Option 1,775 0.1% 425,498 0.1%

Replanted 385,709 11.9% 15,091,790 2.7%

Unharvested 200,400 6.2% 65,601,118 11.7%

Uninsured Loss 304 0.0% 0.0%

Grand Total 3,241,587 100.0% 561,273,721 100.0%

* Records labeled “NULL” stage description occurred for five CAT policies in Poinsett County, AR in 2011. The cause of loss was identified as 

flood.

Use of the tiller factor is not explicitly identified in the P21 data. The Contractor does not note 

this omission to be a flaw in the data collected to administer the crop insurance program, but 

instead is merely noting that absence of this information requires reasonable judgements about 

which loss records may have involved its use. The only definitive information about potential 

use of the tiller factor can be found with respect to replanting payments. It is a given that the 

determination to allow most replanting payments must be based on the early season crop 

conditions, most likely before tillering has occurred. As demonstrated in Table 5, replanted 

acres constituted nearly 12 percent of all determined acres but less than 3 percent of all payments 

to producers during the years 2003-2014.

A higher value than 2.5 for the tiller factor may have disallowed some of the replanting 

payments. There is no way analytically to determine if this is true because the data included in 

the type 21 record merely justify the amount allowed, not the decision to make the payment. 

But, given the magnitude of replanting payments relative to total indemnities, it is evident that a 

higher factor would not have had a material effect on the overall loss costs of the Rice Crop 

Insurance Program.

The other source of potentially avoidable payments falls under the stage descriptor 

“Unharvested.” The only part of these payments that would be affected is represented by early 

season losses of such severity that the producer elects to abandon the crop rather than incur 

further expense for maintaining it to maturity. Accordingly, the producer will file a notice of 

loss and seek to obtain the consent of the AIP to abandon43 the acreage.44 The loss adjuster will 

appraise the acreage to establish the amount of production that would be expected given normal 

 

43 Abandon means “failure to continue to care for the crop, providing care so insignificant as to provide no benefit to the crop, or 

failure to harvest in a timely manner, unless an insured cause of loss prevents you from properly caring for or harvesting the 

crop or causes damage to it to the extent that most producers of the crop on acreage with similar characteristics in the area

would not normally further care for or harvest it” (Common Crop Insurance Policy Basic Provisions, Section 1).

44 Failure to obtain consent will result in an appraisal of not less than the production guarantee per acre.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 17 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

crop development to maturity. This appraised amount establishes the amount of production to 

count. An indemnity may or may not be paid on the basis of the appraisal. If the abandoned 

acres represent only a portion of a unit, the production from the remainder of the unit will be 

included in the production to count. However, the acres in stage “UH” are reported separately in 

the Type P21 records.

The Contractor attempted to estimate the amount of potential loss avoidance that might be 

achieved if the tiller factor could be increased based on scientific evidence. However, not all the 

payments to producers that are classified under “Unharvested” are not due to early season, pretillering appraisals. Accordingly, the Contractor established criteria to extract Type P21 records 

that might be included in this limited category. The criteria were:

1. Field 33 (harvested production quantity) must be less than field 34 (production to count 

quantity).

2. The primary date of damage must be less than 61 days after the date planting was 

completed.

3. The stage code (field 16) must be “UH” (unharvested).

Field 34 of the Type P21 record determines the amount of the indemnity since that amount is 

subtracted from the loss guarantee to establish the unit deficiency. The instructions for the Type 

P21 record state that field 34 “must equal the sum of the Net Harvested, Net Allocated and Net 

Appraised Production. Adjusted for moisture and quality.” The instructions for field 33 state 

that this value “must be less than or equal to the Production to Count Quantity, otherwise 

empty.” The rationale for using this criterion in establishing the potential loss avoidance that 

might be achieved if the tiller factor could be increased based on scientific evidence is that any 

record representing an appraisal will have zero harvested production quantity but a non-zero 

production to count quantity (the result of the appraisal). A total of 4,536 Type P21 records for 

the period 2003-2014 were identified by this criterion.

The second criterion is based on agronomic evidence that tillering should be complete by 

approximately 60 days after the crop is planted.45 This, of course, is not an iron-clad rule. A 

diagram in the publication Arkansas Rice Production Handbook46 (page 10) indicates that 

tillering can be completed in as little as 44 days under good conditions but completion of tillering 

may require 89 days under less favorable conditions. A total of 1,867 Type P21 records from the 

4,536 identified by the first criterion met this second criterion.

The third criterion identifies those records for which the acreage was not harvested. The second 

criterion is not sufficient because while damage could have occurred within the 0 – 61 day 

window it is possible the crop was maintained until harvest. This third criterion identified those 

records for which the harvested production quantity is less than the production to count quantity 

and that incurred damage within 60 days of completion of planting and on which the acreage 

 

45 This represented a generalized phenology for the completion of tillering in mid-season rice presented in Global Rice Science 

Partnership, Research Program on Rice, 2013, Rice Almanac, Fourth Edition, page 7, http://books.irri.org/9789712203008

_content.pdf, accessed March 2016; and in Ricepedia, undated, Growth Phases, http://ricepedia.org/rice-as-a-plant/growthphases, accessed March 2016.

46 Arkansas Rice Production Handbook. MP 192. Edited by Jerrod T. Hardke. University of Arkansas Division of Agriculture. 

Cooperative Extension Service. Little Rock, AR. The diagram in Table H of the LASH appears to be the same as that 

contained in the Arkansas Rice Production Handbook, but it does not contain the legend indicting number of days.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 18 Risk Management Agency

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restrictions on the title page of this report. Order Number D16PB00137

remained unharvested. A total of 782 records were identified by this criterion. These 

represented 84,003 determined acres and just under $30 million of indemnities for the 12 years

(2003-2014), which equate to approximately 2.5 percent of indemnified acres and 5.3 percent of 

all payments to producers. The Contractor believes the criteria provide a reasonable 

approximation to determine the frequency of early season appraisals and the share these 

represent of indemnities.

Very few changes would be needed in the LASH if one or more additional tiller factors are 

needed. Table C would be expanded, perhaps by variety (as is the case with Table E). In the 

simplest case, the expansion would simply separate hybrid types from traditional types, each 

with a unique tiller factor. In addition, some minor modifications to the instructions contained in 

Section 6B(2) would be needed. The only intent of these changes would be to emphasize that the 

appropriate tiller factor is to be extracted from Table C. These observations are applicable only 

if it is possible to determine an appropriate tiller factor.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 19 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

IV. DATA COLLECTION

The objective of the first TO under this contract “is to conduct research and determine the 

appropriate tillering factor(s) for conventional and hybrid rice varieties, which are used while 

performing rice appraisals...”

47

 Ultimately the purpose of the appraisal referenced in the SOW 

is to obtain an estimate of the amount of production lost. The loss is a function of the expected 

yield if the field had not experienced a loss and the expected yield for the field affected by the 

loss if the field were maintained to maturity. The estimate of the expected yield for the field 

experiencing the loss if the crop were maintained to maturity is determined using a variety of 

observations as well as parameters published in the Rice LASH.48 The tiller factor may be one 

of those parameters depending on the date of the loss and the decision of the producer regarding 

whether or not to abandon the damaged acreage. The Contractor proposed gathering data on 

tillering from acceptable data sources to determine whether inbred and hybrid rice varieties have 

significantly different potential to produce tillers. Due to the nature of the requisite data, the 

anticipated sources of the data were extension agents involved in rice breeding and production 

and seed company agronomists whose research might include collection of tillering data.

Despite our extensive data collection efforts, neither seed companies nor extension agents

provided data on average numbers of tillers per plant, much less on tillering by variety, locale, or 

plant density. Ultimately, one expert explained the lack of responses, stating: “The issue I have 

is why one would consider tiller number at all when looking at potential yield [following a] loss. 

To the industry, a rice plant includes tillers. We do not look at tillers as separate plants. Using 

just a plant density measurement [following a loss] would be more uniform and to me a more 

accurate assessment of yield loss... Most of the universities that conduct rice research have these 

studies [on plant density correlations with yield] for each variety. Also [plant density] is the 

industry standard as whether to replant a field or not.”

49 Based on this insight, it is reasonable to 

conclude that the lack of response to the queries was based on the potential that these data simply 

do not exist.

Recognizing the importance of this observation, the Contractor undertook studies on the 

literature for rice yields and for tillering to establish if it might be possible to determine the 

appropriate tiller factor(s) for conventional and hybrid rice varieties from this literature or if it 

might be feasible to conduct field trials to establish the appropriate tiller factor values. The 

results of these research efforts are presented in the two sections that follow.

 

47 USDA, RMA, 2016. Solicitation for Rice Loss BPA (Loss Adjustment Policy & Procedure Support for the Rice BPA), 

Statement of Work: Tillering Factors for Hybrid Rice, page 2 of 5.

48 The actual process used for loss adjustment for early season loses for rice is described in more detail in the preceding section.

49 Dr. S. Bottoms, Technical Services Director, Horizon Ag. Horizon Ag has created unique partnerships with technology 

providers, seed companies and universities to brings novel seed technologies and advanced germplasm for rice to market.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 20 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

V. COMPONENTS AFFECTING RICE YIELDS

Ultimately, crop insurance for both yield and most revenue products is based on yields, requires 

an assessment of yields actually realized and yield potential. Luis Espino, Rice Farm Advisor 

and Chair of the Rice Workgroup at the University of California, describes the contributions of 

various yield components of rice with the following formula:

YIELD (weight/unit area) = Panicles/unit area X number of spikelets/panicle X 

number of filled grains/spikelet X kernel weight50

The reader will note, tillering is not an element of Espino’s formula. Yet tillering is an important 

element of the architecture of plants in the genus Oryza. Tillering assures that a seedling 

ultimately produces sufficient foliage to capture an optimal amount of the insolation impacting 

the location where the plant is growing. In other words, tillers generally ensure the formation of 

dense foliage and development of multiple seed heads (panicles).

It should be noted tillering rates are heavily influenced by environmental attributes. For 

example, when soil moisture is low, grasses tend to develop deep root systems instead of broad 

lateral stem systems. Under these circumstances tillering is inhibited. However, because all 

insured rice is irrigated, as long as the insured maintains an appropriate irrigated practice as 

defined in the Document and Supplemental Standards Handbook (FCIC-24040 (06-2015)), the 

tillering of FCIC insured rice should not be limited by soil moisture.

While Espino’s formula provides a reasonable mechanism for a producer to understand the 

general elements of the plant’s architecture contributing to yield, for the purposes of analyzing 

the tiller factor, it is important to recognize that panicles can form either from main culm (the 

primary stem growing directly from the seedling) or from tillers; that not all tillers are productive 

(i.e., producing panicles); that the number of spikelets on a primary panicle is likely to be larger 

than the number on a panicle forming from a tiller; and that the number of filled grains is 

potentially different from one panicle to another.

Tillering in rice begins during the vegetative stage of rice development after the fourth true leaf 

is fully emerged. The nodes during this stage are close to the ground with very short internodes. 

While at this stage it appears a whorl of leaves develops at a single node, in fact each leaf 

develops from a separate node that has the potential to produce both a primary tiller and a root. 

Each node has an axillary meristem. The meristem producing the tiller at the first node is 

released from inhibition when the fourth leaf emerges. When the fifth leaf emerges, the 

meristem at the second node is released from inhibition, and so on. Tillers emerging in this way 

from nodes in the main stem are called primary tillers. Consequently the potential for 

development of primary tillers is only limited by the number of leaves that develop in the 

compressed (i.e., vegetative) growth stage. It is common that there are five leaves in this 

compressed region of the stem, which would provide the potential to form five tillers. However,

 

50 Espino, L., 2014, Rice Yield Components, UC Rice Blog: California Rice Production, 

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14826, accessed February 2016.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 21 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

the number of tillers that actually develops is influenced by available light (which includes 

shading from competition), nutrients, and available moisture.51

Primary tillers development stops when the panicle on the plant begins development. This marks 

the start of the reproductive phase. At this point, tillers called secondary tillers can branch out 

from preexisting tillers, filling most or all the space in the field not shaded by plants.52

The number of panicles in a unit area (usually per foot2in the U.S. literature on tillering) is 

therefore determined by both the number of established seedlings and the number tillers 

produced by each established seedling. In a stand with 15 to 20 plants/ft2, each plant will 

produce one to 3 tillers on average. This number is comparable to the tiller factor in the current 

Rice LASH. However, when a stand has only 5 to 7 plants/ft2,each plant may produce up to 

dozen tillers, including both primary and secondary tillers.53 Fageria in his treatise on rice yield 

physiology noted: “I have always been amazed at the capacity of rice plants to adapt to the 

conditions of the field, producing more tillers in thin stands and less tillers in dense stands. 

[Furthermore] tillering is one of the important stages that can be most influenced by management 

practices.”54

While numerous factors affect the development of productive (i.e., grain producing) tillers, from 

the perspective of publishing a tiller factor for use in insurance adjustment, it appears the most 

important is the role of stand density. As the stand density increases from 10 to over 40 per 

foot2, the number of productive tillers per plant decreases by as much as 60 percent, while the 

yield per unit area may simultaneously increase (although not in a linear fashion).

55

 A typical 

recommendation for stand density for rice is 15 to 25 plants per foot2.

56

However, the tiller factor is used to adjust losses of vegetative plants. In other words, the tiller 

factor is used to adjust losses after a stand density has been reduced. Consequently, stand 

densities of less than 15 per foot2, and perhaps much less than 15 per foot2 must be considered. 

By extrapolation of the values presented in the 2012 Espino report, at a plant density of 5 per 

foot2as many as 7.5 productive tillers per plant might be expected and as the plant number per 

square foot decreases below that level, the surviving plants could be expected to produce a 

number of tillers limited only by their biological potential.

 

51 Moldenhauer, K., C.E. Wilson Jr., P. Counce, and J. Hardke, University of Arkansas Division of Agriculture Cooperative 

Extension Service, 2013, Arkansas Rice Production Handbook: Rice Growth and Development, J.T. Hardke, Editor, pages 9-

20.

52 Espino, L., 2012, Rice Tillering, UC Rice Blog: California Rice Production, 

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=7779, accessed February 2016; Linscombe, S., 2012, Understanding 

of Growth Stages is Critical in Rice Production, 

http://www.lsuagcenter.com/portals/our_offices/research_stations/rice/features/publications/understanding-of-growth-stagesis-critical-in-rice-production, accessed April 2016.

53 Espino, L., 2014, Rice Yield Components, UC Rice Blog: California Rice Production, 

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14826, accessed February 2016.

54 Fageria, N.K., 2007, Yield Physiology of Rice, Journal of Plant Nutrition 30:843-879.

55 Espino, L., 2012, Rice Tillering, UC Rice Blog: California Rice Production, 

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=7779, accessed February 2016.

56 Runsick, S., and C.E. Wilson Jr., 2014, Rice Tillering, Rice Seeding Rate: Recommendations for Arkansas, 

https://www.uaex.edu/publications/PDF/FSA-2157.pdf, accessed April 2016; University of California Rice On-line, 2016, 

Seeding Rate Calculator, http://rice.ucanr.edu/Rice_Calculator/, accessed April 2016.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 22 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

For most rice plants almost all the vegetative nodes have the potential to produce a tiller, but 

only at the appropriate time in the vegetative cycle. Therefore, for an early season loss, 10 to 15 

tillers might form as there may be as many as 15 vegetative nodes and the tillers themselves have 

nodes that can produce productive tillers. But for losses closer to the end of the vegetative stage, 

the tillering “recovery” might not exceed the 2 to 4 typically expected since the older nodes have 

passed the period when the tillering potential can be realized.57 Consequently, lower plant 

densities resulting from an early season loss are not likely to result in proportional yield 

reductions as increased tillering compensates for substantial portions of the loss. In contrast, 

tillering of plants in fields where losses occur closer to heading is less likely to compensate for 

the losses.58 

The SOW in the Solicitation for this TO states:

The recommended seedling population for hybrid rice varieties (8-10 per sq. ft. in 

Louisiana and 9-12 per sq. ft. in Mississippi) is about one-half of the 

recommended population of conventional rice varieties (10-20 per sq. ft. in 

Arkansas, 15-25 per sq. ft. in Louisiana, and 12-20 per sq. ft. in Mississippi). 

This is due to the practice of hybrid rice profuse tillering.”

59

However, it is not the seeding rate, but the stand density that ultimately determines yields in 

fields that have not experienced a post-germination loss. Recognizing the impacts of tillering

described above, Espino’s yield component formula can be expanded to better illustrate the role

of tillers on yield as:

YIELD (weight/unit area) = Plants from seed/area X ((Panicles/primary stem60 X 

number of spikelets on panicles/ primary panicle X 

number of filled grains/primary panicle spikelet) + (productive tiller/plant X 

panicles/productive tiller X number of spikelets from productive tiller/panicle X 

number of filled grains/tiller panicle spikelet)) X (kernel weight)61

However, this construct for determining yield or yield potential in the case of an insurable loss

event is too complex to provide a basis for loss adjustment. Therefore the Contractor sought to 

determine if the published literature on tillering alone would support a establishment of one or 

more tiller factors for inbred and hybrid rice independent of the yield data.

 

57 Mohapatra, P.K., R. Patel and S.K. Sahu, 1993, Time of Flowering Affects Grain Quality and Spikelet Partitioning within the 

Rice Panicle, Australian Journal of Plant Physiology 20:231 – 241; Moldenhauer, K., C.E. Wilson Jr., P. Counce, and J.T. 

Hardke, 2014, Rice Growth and Development, Arkansas Rice Production Handbook, pp. 9-20.

58 Jarrod Hardke, J., 2016, Arkansas Rice Update, http://www.arkansas-crops.com/2016/04/15/arkansas-rice-update-15-16/, 

accessed June 2016.

59 USDA, RMA, 2016. Solicitation for Rice Loss BPA (Loss Adjustment Policy & Procedure Support for the Rice BPA), 

Statement of Work: Tillering Factors for Hybrid Rice, page 2 of 5.

60 Primary panicle.

61 Fageria, N.K., 2007, Yield Physiology of Rice, Journal of Plant Nutrition 30:843-879; Espino, L., 2014, Rice Yield 

Components, UC Rice Blog: California Rice Production, http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14826, 

accessed February 2016.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 23 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

VI. RICE TILLERING

This section addresses the question: does the tillering pattern described in the literature support 

the development of tiller factors that could be used to establish yield potential such that:

YIELD (weight/unit area) = Plants/area X tiller factor (panicles/area) X grain factor 

(kernels per panicle) X kernel weight62

The reader will note the similarity of this simplification of the yield formulae presented earlier to

the calculations used in the appraisal process for rice losses that occur prior to the completion of

tillering.

As noted earlier, the rice seedling produces a primary stem using energy stored in the seed. 

Once the primary stem has in turn produced four to five leaves, it becomes self-supporting, no 

longer dependent on the energy stored in the seed. Depending on a number of causes, branches 

can develop from the main stem. Some of these branches, especially in the earliest stages of 

development, have the potential to produce seed. Branches with this attribute in rice are called 

tillers. Although most tillers remain attached to the plant from which they develop, they produce 

their own roots and can consequently behave physiologically as independent entities. Regardless 

of whether the tillers form these independent entities or remain dependent on their “parent” 

plant, they contribute to an increased yield as compared to the yields of plants with fewer tillers. 

However, the extent of the contribution under these two different circumstances may differ.

The amount of tillering, the development of flowers on the tillers, and the development of grains 

from those flowers all depend on the variety of genetic and environmental factors. In rice

breeding programs, several genetic traits are selected to increase yield potential. The yield of 

rice involves three main components: number of panicles per unit area, number of spikelets per 

panicle, and kernel weight.

63

 These components contribute to grain yield to differing extents and 

the contribution of these three components varies with genotype, environmental factors and 

cultivation practice. Plant architecture is in turn affected by these three factors. Rice plant 

architecture is a composite of tiller pattern, plant height, leaf shape and arrangement, and panicle 

architecture. Of these, tiller pattern (including tiller number) is the most affected by 

environmental factors, with the density of the stand being a major factor affecting architecture. 64

The branching that produces tillers is influenced by the frequency of branching, the nature of the 

branches (i.e., whether they are destined to be vegetative or reproductive), and the angle of 

branches. Together these determine the amount of space occupied by the branches and the 

amount of light that can be collected for photosynthesis. When a tiller forms, the axillary 

meristems grow out to form branches that are similar in to the main stem (culm) and 

consequently have a similar (but not identical yield potential) to the main culm. In this way, 

tillering is directly linked to the number of panicles, which in many cases is the most important 

 

62 Fageria, N.K., 2007, Yield Physiology of Rice, Journal of Plant Nutrition 30:843-879; Espino, L., 2014, Rice Yield 

Components, UC Rice Blog: California Rice Production, http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14826, 

accessed February 2016.

63 Peng, S., R.C. Laza, R.M. Visperas, A.L. Sanico, K.L. Cassman, and G.S. Khush, 2000, Grain yield of rice cultivars and lines 

developed in Philippines since 1996, Crop Science 40: 307–314.

64 Yang, X-C. and C-M Hwa, 2008, Genetic modification of plant architecture and variety improvement in rice, Heredity 101: 

396–404, http://www.nature.com/hdy/journal/v101/n5/full/hdy200890a.html#bib35, accessed April 2016.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 24 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

basis of yield. The grain weight is under much stronger genetic control. The number of tillers is 

influenced by numerous environmental factors, which are limited by the genetic potential of the 

rice.65

Genetics, which is the basis of breeding programs, does influence tillering in rice. Mutations 

have been identified that affect the number of tillers, the location of tiller potential, and the tiller 

angle, although not all these factors are affected by a single gene.66 Furthermore there are gene 

interactions, including interactions that can be affected by whether the plant is inbred or hybrid. 

The growth of axillary meristems into branches in some plants is controlled primarily by plant 

growth hormones.67 Although similar control has not been demonstrated in rice, other genetic 

patterns in rice regarding both branching and height are similar to those of the plants where these 

mutations have been identified. 68 Finally, other aspects of the rice architecture have been shown 

to have typical patterns of hormonal control.69

As noted earlier, the angle between the main stem and its tillers contributes to the agronomic 

performance of rice.

70 While the potential angle is influenced by genes considered in breeding 

programs, the actual angle of a branch is also impacted by the stand density and especially by 

shading. Consequently a stand in a loss unit is likely to have tiller angles quite different from 

those in a full stand.

Domesticated varieties of rice are less branched than their wild progenitors allowing closer 

planting and less self-shading.

71

 Normally, commercial rice plants do not have higher branches 

where the stem internodes elongation has occurred. Some mutants produce fewer tillers where 

the stem internodes have not expanded.72 These would result in varieties that are more compact 

and because of the limited tillering would have a lower tiller factor. Others mutations identified 

in Oryza species (but not yet in Asian rice) produce a creeping habit where the tiller angle results 

in greater expansion of the plant complex into un-shaded areas. Variation of tillers angles of O. 

rufipogon is depends on water availability and position in the stand relative to other rice plants.73

 

65 Ibid.

66 Li, X., Q. Qian, Z. Fu, Y. Wang, G. Xiong, D. Zeng, W. Xiaoqun, L. Xinfang, T. Sheng, H. Fujimoto, Y. Ming, L. Da, H. Bin, 

and L. Jiayang Li, 2003, Control of tillering in rice, Nature 422: 618–621.

67 Bennett, T., T. Sieberer, B. Willett, J. Booker, C. Luschnig, and O. Leyser, 2006, The ArabidopsisMAX pathway controls 

shoot branching by regulating auxin transport. Curr Biol 16: 553–563, http://ac.els-cdn.com/S0960982206011195/1-s2.0-

S0960982206011195-main.pdf?_tid=6511e7de-07d8-11e6-98ed00000aacb35e&acdnat=1461253847_5606564f00a9e9bfd33af897114568bc, accessed April 2016.

68 Yang, X-C. and C-M Hwa, 2008, Genetic modification of plant architecture and variety improvement in rice, Heredity 101: 

396–404, http://www.nature.com/hdy/journal/v101/n5/full/hdy200890a.html#bib35, accessed April 2016.

69 Ishikawa, S., M. Maekawa, T. Arite, K.Onishi, I. Takamure, and J. Kyozuka, 2005, Suppression of tiller bud activity in 

tillering dwarf mutants of rice, Plant Cell Physiology 46: 79–86, http://pcp.oxfordjournals.org/content/46/1/79.full.pdf+html, 

accessed April 2016.

70 Xu, Y., S.R. McCouch and Z. Shen, 1998, Transgressive segregation of tiller angle in rice caused by complementary gene 

action, Crop Science 38: 12–19.

71 Doust, A., 2007, Architectural evolution and its implications for domestication in grasses. Annals of Botany (London) 100: 

941–950, http://aob.oxfordjournals.org/content/100/5/941.full.pdf+html, accessed April 2016.

72 Yang, X-C. and C-M Hwa, 2008, Genetic modification of plant architecture and variety improvement in rice, Heredity 101: 

396–404, http://www.nature.com/hdy/journal/v101/n5/full/hdy200890a.html#bib35, accessed April 2016.

73 Gao, L., S. Ge and D. Hong, 2000, A preliminary study on ecological differentiation with in the common wild rice Oryza 

rufipogon Griff., Acta Agronomica Sinica 26: 210–216, http://caod.oriprobe.com/articles/2590891/

A_Preliminary_Study_on_Ecological_Differentiation_within_the_Common_Wi.htm, accessed April 2016.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 25 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

In summary, it appears most of the research on rice varieties, including research on inbred and 

hybrid rice varieties, focuses on yield, resistance to localized perils, and quality of the grains

produced. The tillering potential of rice and the capacity of varieties to respond to environmental 

conditions with production of tillers are so highly variable that no tiller factor or factors that 

could be used for loss adjustment can be derived from the academic literature focused on 

tillering, tillering genetics, or tillering physiology. Yu and his coworkers note: “Tillering is 

regulated more by cultural practices and environment than by genetics.” 74 Yet the differences 

between inbred and hybrid rice, or for that matter between different varieties of inbred rice, are 

fundamentally genetic. Consequently, the question of whether hybrid rice should have a 

different tiller factor than inbred rice is moot, while the primary impacts of cultural practices and 

environment are best captured in an insured’s actual production history rather than in some 

abstract factor or factors.

 

74 Yu B, Lin Z, Li H, Li X, Li J, Wang Y et al. (2007). Tac1, a major quantitative trait locus controlling tiller angle in rice. The 

Plant Journal 52: 891–898.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 26 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

VII. DISCUSSION AND CONCLUSIONS

This section of the report provides a summary of the conclusions the Contractor reached 

concerning the objective of the research described in the TO in the SOW75 which states: 

“determine the appropriate tillering factor(s) for conventional and hybrid rice varieties, which are 

used while performing rice appraisals.” This objective can be restated as a research question: 

“What are the appropriate tiller factors to use while performing rice appraisals for conventional 

and hybrid rice varieties?” The Contractor’s conclusions regarding this research question 

include:

 Since yield in rice is a function of so many genetic and environmental factors, academic 

and commercial yield studies focus on relative yields for individual varieties and not on 

specific yield components such as tiller numbers.

 The timing of a loss of rice plants prior to tillering has a major impact on the number of 

tillers that can be produced.

 Consequently, almost all available information on tiller numbers is subjective rather than 

quantitative and focuses on tillering in fields that have not experienced a loss event (i.e., 

the stand is normal).

 There is a great disparity in the subjective opinions experts express concerning tillering 

potential of commercial rice in general (Appendix B).

 Moreover, rice yields are influenced substantially by management practices, but only in 

part because tiller numbers are affected by management practices.

 The Contractor identified no published data that could be used to establish appropriate 

new tiller factors for rice crop insurance appraisals for inbred and hybrid rice varieties for 

“tillering incomplete” appraisals.

 Private data to establish appropriate new tiller factors for rice crop insurance appraisals 

either do not exist or if they exist they are considered proprietary and will not be shared 

for maintenance of the rice crop insurance products.

As a result of the above-mentioned conclusions, the Contractor believes there is no objective

support for the statement in the contract that differences in recommended planting densities are 

“due to the practice of hybrid rice profuse tillering.”76 To limit appraisals for rice loss 

adjustment using tiller factors, it may be appropriate to add language in section 6A of the Rice 

LASH that might state:

“WHENEVER POSSIBLE, delay any appraisal when damage occurs before 

heading is complete if it is not clear how tillering and heading will contribute to 

the appraised yield. If the insured wishes to replant, abandon the field, or put a 

field to other uses, it may be beneficial to require that representative samples of 

the field be maintained for final entries on the Production Worksheet.”

Since so many factors affect the impact of tillering on yield, the Contractor concludes field trials 

to establish tiller factors for hybrid varieties would be very difficult to conduct, of limited 

potential utility, and extremely costly. Due to substantial tillering differences between varieties 

and not just between inbred and hybrid groups, field trials would need to address the commercial 

 

75 USDA, RMA, 2016. Solicitation for Rice Loss BPA and Order 1 (D16PS00016), Loss Adjustment Policy & Procedure Support 

for the Rice BPA for Order Number D16PB00137, Tillering Factors for Hybrid Rice, page 2 of 5.

76 Ibid.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 27 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

varieties being planted and a variety of planting densities for all those varieties. Introduction of 

new varieties would require an ongoing effort to expand and update the tiller factor table (and 

perhaps the tiller to pound yield factors) for different varieties (and perhaps types), locales, and 

loss dates at the least. There would need to be data collection to address different timings of the 

loss events, different causes of loss, different soil types, and differences in seeding practices. 

Long-term yield data series would need to be collected to compare yields in loss units and in 

units not unaffected by a loss. Careful supervision of post-loss management practices would be 

required. In summary, the permutations and combinations of the conditions that would need to 

be evaluated would exceed the capacity for typical field trials. There is no evidence these costly 

and time-consuming efforts would produce appropriate tiller factor values for loss adjustment of 

all rice production, production of inbred and hybrid rice, or even for production of a single rice 

variety.

Furthermore, for all the same reasons, and because of the burden it would impose on AIPs and 

RMA, the Contractor concludes collecting the necessary data through changes in the data 

requirements for PASS could not be justified since the likelihood of collecting adequate 

measures of all the variables needed to develop statistically significant tiller factors for subsets of 

insured rice is extremely small.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 28 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

VIII. RECOMMENDATIONS

This section of the report provides the Contractor’s recommendation regarding the existing tiller 

factor used in adjustment for losses of insured rice that occur prior to the completion of tillering. 

The SOW provides the following guidance regarding these recommendations:

Any recommendations or improvements the contractor identifies must adhere to 

sound statistical procedures and standard actuarial principles that provides 

meaningful risk management benefits to the insured(s) and to the Government. 

The contractor should clearly state and support all assumptions, findings, and 

determinations in sufficient detail to enable independent researchers or RMA 

personnel to reproduce the analysis for validation. Recommendations need to be 

cost effective and able to be administered from the perspective of the insured and 

the Approved insurance Providers (AIPs).77

“Actuarial science is concerned with the development of models which approximate the 

behaviour of reality and have a degree of predictive power... Sound statistical procedures

[require that quantitative recommendations be based on reliable data. In the absence of such 

data, actuarial science may accommodate] low-level generalisations, recognising the limited 

nature of available regularities. [However,] knowledge of the variations in the specific locality 

of interest” is essential to an appropriate actuarial analysis. 78

The Contractor has concluded data limitations and the numerous variations in tillering resulting 

from location, soil type, and management practices, and other factors render any attempt to

provide different tiller factors will introduce substantial burdens on the AIPs and RMA without 

providing more accuracy and precision in estimating the yield that might have been obtained if 

the crop had been maintained. Therefore the goals of actuarial science as detailed above will not 

have been met by this effort. Consequently, the Contractor recommends RMA develop an 

alternative to the tiller factor approach for appraisal of early season losses in rice, including for 

appraisals focused on replant payments. One such alternative would be to require the insured to 

maintain the crop until an appraisal can be completed following tillering or perhaps even 

following heading. This approach would address the impact of plant density on yield, the 

potentially variations in tillering among different rice varieties, the impact of management 

practices on tillering, and the fact the timing of a loss event will impact the number of tillers that 

can be produced. Another alternative would be to develop a direct surviving-plant (stand 

density) to yield factor that eliminates the intervening calculations used in the current earlyseason-loss appraisal procedures. There are likely other alternatives that could be used to

address loss adjustment for early season losses insured under the FCIC Rice Crop Provisions. A 

specific recommendation regarding the most appropriate alternative to the existing approach 

would require substantial added research beyond the scope of this Task Order 

According to the solicitation, the insurance industry is concerned the current procedures for 

adjustment of early season losses of rice might not be appropriately addressing the yield potential 

of appraised fields because “the tillering factor currently used while performing rice appraisals is 

 

77 Ibid., pages 2 and 3.

78 Pemberton, J.M., 1999, The Methodology of Actuarial Science, The British Actuarial Journal, 5:115-195. British spellings of 

terms are quoted as published.
Tillering Factors for Hybrid Rice

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restrictions on the title page of this report. Order Number D16PB00137

based on conventional rice varieties only,”79 To address this concern,” the Contractor 

recommends RMA consider, at least in the short run, adding stronger language in section 6A of 

the Rice LASH that indicates the value and utility of delaying appraisals when tillering is 

incomplete.

 

79 USDA, RMA, 2016. Solicitation for Rice Loss BPA (Loss Adjustment Policy & Procedure Support for the Rice BPA, 

Statement of Work: Tillering Factors for Hybrid Rice, page 2 of 5.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 30 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

IX. IMPACT ANALYSIS

This section of the report provides a summary of the impact of the Contractor’s recommendation

on RMA, the AIPs, and the insureds. If the recommendation regarding adding language in 

section 6A of the Rice LASH is implemented, that language will need to be drafted and 

incorporated into the Rice LASH. 

Since the recommended changes regarding development of an alternative to the tiller factor 

procedures for appraisal of early season losses in rice, including for appraisals focused on replant 

payments, substantially impact loss adjustment, if implemented, AIPs should provide appropriate 

notice to their adjusters. This notice should be accompanied by a copy of any new Rice LASH

(or slipsheets) issued by RMA. Adjusters would likely need to make an additional visit to assess 

some early season losses. The preliminary visit would document the occurrence of a loss and the 

cause of loss. The second would be to conduct the appraisal if the crop is maintained through 

heading. This requirement is not unusual when the extent of a loss cannot easily be established 

during the initial visit to a field.

Under the proposed changes, AIPs will require some insureds to maintain fields affected by 

losses prior to the completion of tillering until an appraisal following the completion of tillering 

can be made. This adds to the burden on the insured. Due to the requirement for irrigation of 

rice crops, the added burden for the insured may be very great. However, the number of insureds 

affected by this change in any year is small, especially when compared to the number of units 

earning premium. Requiring maintenance of fields affected by losses prior to the completion of 

tillering is not regularly used for other small grains. Early losses to barley, oats, rye, and wheat 

are all adjusted using a tiller factor.80 Maintaining representative samples, as opposed to 

maintenance of entire fields, is required for some insured grain crops grown for seed.

81

Furthermore, maintaining at least appropriate representative samples is recommended for some 

insured crops which like rice have the ability to recover from damage by developmental 

strategies that make it difficult to predict yields in the earlier stages of development.82

Consequently, a recommendation that rice fields be maintained until an appropriate appraisal can 

be made is not without precedent. However, in contrast, RMA does not offer replant payments 

for American upland or extra long staple cotton. Therefore, establishing crop provisions for rice 

which eliminate replant payments would also be supported by precedent. 

In conclusion, the proposed development of an alternative to the rice tiller factor procedures for 

adjustment for early season losses are justified based on the biology of the rice crop:

 Different rice varieties have different and non-quantifiable tillering potential;

 Number of tillers differs based on planting density;

 Number of tillers differs based on soil type;

 Number of tillers differs based on planting procedures;

 Number of tillers is influenced by the health of the surviving plant;

 

80 That such factors are used for other grains does not diminish the importance of the numerous issues that argue against use of a 

tiller factor in rice loss adjustment.

81 See for example the Hybrid Seed Loss Adjustment Standards Handbook, pages 17 and 22, which require insureds with losses 

to sorghum and corn seed to maintained representative samples until an appropriate appraisal can be made.

82 See for example the Sesame Pilot Loss Adjustment Standards Handbook (FCIC-25015 (11-2014)), page 13, which states: 

“Whenever possible, require the producer to maintain a portion of the crop so the Harvested Production Method can be used.”
Tillering Factors for Hybrid Rice

Use or disclosure of information or data 31 Risk Management Agency

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restrictions on the title page of this report. Order Number D16PB00137

 Not all tillers produce productive plants;

 Secondary tillers are less productive than primary and some of the breeding efforts have 

affected the extent to which tillering beyond primary tillering occurs;

 Yield is influenced substantially by management practices, only in part because tillering 

is influenced by management practices; and

 The timing of a loss event prior to tillering will impact the number of tillers that can be 

produced.

The burden imposed by implementation of the proposed changes is modest compared to the 

benefit from a process that better establishes an appropriate value for the production to count.
Tillering Factors for Hybrid Rice

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Appendix A

Representative Recommended Rice Varieties and Varieties 

under Investigation in the United States
Tillering Factors for Hybrid Rice

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contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Table A1. Brief Description of Southern State Conventional, Clearfield and Hybrid Rice Cultivars

Variety/Hybrid Year Released and State Highlights

Arize QM1003 2009 – Bayer Cropscience A mid-season, long-grain hybrid with good grain and milling 

yield.

Banks 2004 – Arkansas Ashort-season, long-grain LaGrue-type rice with blast

resistance.

Bengal 1992 – Louisiana Ashort-season, semi-dwarf, medium-grain with good yield

potential and milling quality. It has a preferred large grain size.

Bowman 2008 – Mississippi Ashort-season, long-grain rice with good grain and milling 

yield and high amylose content.

Caffey 2011 – Louisiana Asemi-dwarf, short-season, medium-grain rice variety with

excellent yield potential and milling quality. Caffey is

characterized by a very bold uniform milled grain. It is

moderately susceptible to sheath blight, blast and sheath blight.

Catahoula 2008 – Louisiana Ashort-season, semi-dwarf long-grain with good grain and

milling yield and resistance to rice blast.

Cheniere 2003 – Louisiana Ashort-season, semi-dwarf long-grain with good yield

potential, less oil in bran than Cocodrie, and improved

straighthead tolerance.

CL111 2009 – BASF, Horizon Ag A very short-season, semi-dwarf long-grain similar to Trenasse 

with high tolerance to Newpath herbicide. It is very susceptible

to sheath blight and susceptible to blast and straighthead.

CL131 2004 – BASF, Horizon Ag A very short-season, semi-dwarf long-grain similar to Cocodrie

with high tolerance to Newpath herbicide. It is very susceptible

to sheath blight, moderately susceptible to blast and very

susceptible to straighthead.

CL142 AR 2009 – BASF, Horizon Ag Ashort-season long-grain Clearfield variety similar to Wells

with excellent yield potential and good milling potential. It is

susceptible to blast and moderately susceptible to sheath blight 

and straighthead.

CL151 2008 – BASF, Horizon Ag Ashort-season, semi-dwarf long-grain Clearfield rice similar to

Cypress with high tolerance to Newpath herbicide. It is very 

susceptible to sheath blight, susceptible to blast and

susceptible to straighthead.

CL152 2011 – BASF, Horizon Ag Ashort-season, semi-dwarf long-grain Clearfield rice similar to

CL151 with high tolerance to Newpath herbicide. It has

excellent yield potential and milling quality. CL152 is 

susceptible to sheath blight and moderately susceptible to both

blast and straighthead.

CL161 2002 – BASF, Horizon Ag Ashort-season, semi-dwarf long-grain Clearfield rice similar to

Cypress with high tolerance to Newpath herbicide. It is very 

susceptible to sheath blight, moderately susceptible to blast

and susceptible to straighthead.

CL162 (MS) 2011 – BASF, Horizon Ag Ashort-season long-grain Clearfield rice variety with

commercially acceptable tolerance to Newpath and Beyond

herbicides. It is a high-yielding variety with very good milling 

quality and excellent straw strength. CL162 is susceptible to

blast, sheath blight and straighthead.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data A2 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Variety/Hybrid Year Released and State Highlights

CL171 AR 2005 – BASF, Horizon Ag Ashort-season, semi-dwarf long-grain Clearfield rice similar to

Wells with high tolerance to Newpath herbicide. It is 

moderately susceptible to sheath blight, susceptible to blast 

and moderately susceptible to straighthead.

CL181 AR 2009 – BASF, Horizon Ag Ashort-season, semi-dwarf long-grain Clearfield rice with

good yield potential and milling yield potential. It is very 

susceptible to sheath blight and susceptible to blast.

CL261 2009 – BASF, Horizon Ag Ashort-season, semi dwarf medium-grain Clearfield rice with 

good yield potential and milling quality. It is moderately 

susceptible to sheath blight and blast and susceptible to

straighthead and bacterial panicle blight.

CL XL729 2006 – Rice Tec, Inc. Ashort-season long-grain hybrid with excellent yield potential, 

good milling yield potential, and good disease resistance.

CL XL730 2005 – Rice Tec, Inc. A short-season long-grain hybrid with excellent yield potential, good

milling yield potential, and good disease resistance.

CL XL745 2007 – Rice Tec, Inc. A short-season long-grain hybrid with excellent yield potential, good

milling yield potential and good disease resistance.

CL XL746 2008 – Rice Tec, Inc. A short-season long-grain hybrid with excellent yield potential, good

milling yield potential and good disease resistance.

Cocodrie 1997 – Louisiana A short-season, semi-dwarf long-grain with good yield potential and

milling quality.

Cybonnet 2004 – Arkansas A short-season, semi-dwarf long-grain with good yield potential and

excellent milling quality similar to Cypress. It has blast resistance

similar to Katy.

Cypress 1992 – Louisiana A mid-season, semi-dwarf long-grain with good yield potential and

excellent milling quality and excellent seedling vigor.

Drew 1996 – Arkansas A mid-season long-grain with average yield potential and milling

quality. It is blast resistant, straighthead tolerant, and has a larger

kernel size than Kaybonnet.

Francis 2002 – Arkansas A very short-season long-grain with excellent yield potential,

susceptible to rice blast.

Jefferson 1999 – Texas A very short-season, semi-dwarf long-grain variety with good yield

potential. It is moderately susceptible to sheath blight and 

susceptible to blast.

Jupiter 2005 – Louisiana A mid-season medium-grain with excellent yield potential, good

milling quality, and resistance to bacterial panicle blight. It has a

smallerseed size than Bengal.

Kaybonnet 1994 – Arkansas A short-season long-grain with good yield potential and good milling 

quality. It is resistant to rice blast and has a small grain size.

LaGrue 1993 – Arkansas A short-season long-grain with excellent yield potential and variable

milling quality. It is susceptible to rice blast and kernel smut.

Lemont 1983 – Texas A mid-season, semi-dwarf long-grain with good yield potential and

milling quality. It has poor seedling vigor.

Neptune 2008 – Louisiana A mid-season medium-grain with excellent yield potential, good

milling quality, and partial resistance to bacterial panicle blight. It

has a seed size that is similar to Bengal.

Newbonnet 1983 – Arkansas A mid-season long-grain with good yield potential and good milling

quality. It is susceptible to rice blast.

Presidio 2005 – Texas A short-season, semi-dwarf long-grain with good yield potential and

good milling quality.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data A3 Risk Management Agency

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restrictions on the title page of this report. Order Number D16PB00137

Variety/Hybrid Year Released and State Highlights

Rex 2010 – Mississippi A short-season, semi-dwarf long-grain with good yield potential, 

excellent straw strength and very good milling quality. Rex is

susceptible to blast and sheath blight and moderately susceptible to

straighthead.

Roy J 2010 – Arkansas A mid-season, standard-statured long-grain with excellent yield

potential, very strong straw strength, and good milling yield.

Susceptible to blast and moderately susceptible to sheath blight.

Spring 2005 – Arkansas A very short-season long-grain with good yield potential and rice blast

resistance. It is one of the earliest maturing long-grain rice lines.

Saber 2001 – Texas A mid-season, semi-dwarf long-grain with resistance to some rice

blast races. It has yield and quality characteristics similar to

Cypress.

Taggart 2009 – Arkansas A mid-season, standard-statured long-grain with good yield potential 

and large kernel size.

Templeton 2009 – Arkansas A mid-season, standard-statured long-grain with good yield potential

and resistance to all of the know races of rice blast disease in

Arkansas.

Trenasse 2005 – Louisiana A very short-season long-grain with good yield potential. Very

susceptible to sheath blight and straighthead; susceptible to blast.

Wells 1999 – Arkansas A short-season long-grain with excellent yield potential, average

milling quality, kernel size similar to Lemont and susceptible to rice 

blast.

XL723 2004 – RiceTec A very short-season long-grain hybrid with good yield potential, 

average milling quality and resistance to blast and moderately

resistant to sheath blight.

XL753 2011 – RiceTec A short-season long-grain hybrid with excellent yield potential, 

good milling yield potential, and good disease resistance.

Source: Wilson, C.E. Jr., K. Moldenhauer, R. Cartwright, and J. Hardke, University of Arkansas Division of Agriculture Cooperative Extension 

Service, 2013, Arkansas Rice Production Handbook: Rice Cultivars and Seed Production, J.T. Hardke, Editor, pages 25-27.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data A4 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Table A2. Brief Description of Southern State Specialty Cultivars.

Variety/Hybrid Year Released and State Highlights

AB647 1996 – Anheuser Busch Selection from Congui, a Chinese indica rice, that is a long-season

medium- grain with high yield potential and atypical cooking qualities.

Used for brewing.

Baldo Italy A very short-season, large-kerneled medium-grain used for risotto.

Bolivar 2001 – Texas A very short-season long-grain with the same parboiling and canning

properties as Dixiebelle.

Della 1971 – Louisiana Aromatic, mid-season long-grain with low yield potential and average

milling quality that is susceptible to lodging.

Dellmati 1999 – Louisiana A semi-dwarf, aromatic long-grain which elongates when cooked.

Dellmont 1992 – Texas Semi-dwarf, aromatic long-grain with good yield potential and milling 

quality.

Dellrose 1995 – Louisiana A semi-dwarf, aromatic long-grain with high yield potential and good

milling quality. It has grain size similar to Della.

Dixiebelle 1996 – Texas Short-season long-grain with ‘Newrex’ quality; specialty rice used for

canning and steam tables.

Hidalgo 2005 – Texas A semi-dwarf long-grain with good yield potential and milling quality.

Cooking type similar to Toro. It is susceptible to blast and moderately

susceptible to sheath blight.

Jasmine-85 1990 – Texas Aromatic long-grain with good yield potential and poor milling quality.

Jazzman 2008 – Louisiana Aromatic long-grain with good yield potential and milling quality.

Jazzman-2 2010 – Louisiana A semi-dwarf, fragrant long-grain with good yield potential, good milling

quality and very strong aroma.Jazzman-2 is susceptible to rice sheath

blight, bacterial panicle blight and straighthead but moderately resistant

to blast.

JES 2009 – Arkansas/Florida Aromatic long-grain with good yield potential and milling quality.

Koshihikari Japan A premium-quality short-grain with low yield potential and good

milling quality. It is the standard for Japanese quality.

Neches 2005 – Texas A long-grain waxy rice with good yield potential (similar to Lemont) 

used for flour and starch in processing industry. Moderately resistant to

blast and very susceptible to sheath blight.

Pirogue 2002 – Louisiana A short-season short-grain with good yield potential and good milling 

quality.

Sabine 2006 – Texas Short-season long-grain with ‘Dixiebelle’ quality. Similar agronomic

traits as Dixiebelle, with higher yield potential. Specialty rice used for

canning and steam tables.

Sierra 2005 – Texas An aromatic long-grain with the fragrance and cooking qualities of a 

basmati- style rice.

Toro 2 1984 – Louisiana Special-purpose, low amylase and low gelatinization temperature, longgrain rice. Toro 2 cooks moist and sticky like a medium-grain rice.

Source: Wilson, C.E. Jr., K. Moldenhauer, R. Cartwright, and J. Hardke, University of Arkansas Division of Agriculture Cooperative Extension 

Service, 2013, Arkansas Rice Production Handbook: Rice Cultivars and Seed Production, J.T. Hardke, Editor, pages 27.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data A5 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Table A3. California Rice Classification, Commercial Impact, and Tier Designation

Variety CI Non-CI Tier

Long Grain

A-201  1

A-301  1

Aromatic Long Grain Red Rice  2

Calmati-201  1

Calmati-202  1

Donana 

L-202 (not in production) 

L-203 (not in production) 

L-204 (not in production) 

L-205 (not in production) 

L-206 

Long Grain Red Rice  2

P-2 Denosa 

P-3 Isla 

A-202  1

Medium Grain

Black Rice – SWF  2

Calriso  1

Guadiamar 

Hong Kong Black (HKB-102)  2

Kokuho Rose 

KR4 

M-103 (not in seed production) 

M-104 

M-105 

M-201 

M-202 

M-204 (not in seed production) 

M-205 

M-208 

M-209 

M-401 

M-402 

Millrose 

NFD181 

Riz Rouge Camargue  2

Rojito (SunWest)  2

SP-211 

SP-311 

SP-411 

Wehani LWE-218 (Lundberg)  2

85-101-10 

91-130-02 

94-158-01 

95-164-01 

M-206 (formerly 98-Y-242 

Arborio  1

Black Japonica (LBJ-489)  2

Black Rice (SunWest)  2

WRM-3538 

M-207 (formerly 00-Y-805 not in 

seed production) 
Tillering Factors for Hybrid Rice

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restrictions on the title page of this report. Order Number D16PB00137

Variety CI Non-CI Tier

02-PY-021 

02-PY-014 

RRI-321 

RRI -226 

98-102 

02-121 

04-116 

LMR-206  2

Carnaroli (all subtypes)  1

FRC #11 

FRC #22 

00-117 

02-120 

07-122 

LBJ-115  2

Short Grain

A-17  1

A-20  1

Akita Komachi  1

Calhikari-201  1

Calhikari 202  1

Calmochi -101  1

Calmochi -203  1

Calpearl  1

Himenomochi

(formerly PI 504474)

 1

Hitomebore  1

Koshihikari  1

NFD 108  1

NFD 109  1

S-102 

S-201 (not in seed production) 

S-6 

SP-2  1

04-302 

Sasanishiki  1

Surpass  1

WRS-4431  1

Kogane Mochi  1

Calamylow-201

(formerly BL-1)  1

BL-2 (not in production)  1

Vialone Nano  1

Carnaroli (all subtypes)  1

Source: California Rice News, 2016, Varieties Currently Reviewed, 

http://www.calricenews.org/wp-content/uploads/2016/01/Varieties-currentlyreviewed.doc, accessed April 2016.

Commercial Impact

 Commercial Impact Tier 1 – commingling with Calrose will reduce value or increase handling or 

sorting costs. Standard industry practices can mitigate.

 Commercial Impact Tier 2 – commingling with Calrose will reduce value or increase handling or 

sorting costs. Standard industry practices and additional planting restrictions and handling 

practices can mitigate.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Appendix B

Frequency of Rice Tillering as Documented in 

Representative Academic Literature
Tillering Factors for Hybrid Rice

Use or disclosure of information or data B1 Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

restrictions on the title page of this report. Order Number D16PB00137

Table B1. Frequency of Rice Tillering as Documented in Representative 

Academic Literature

Tillers per Plant Authors Year Primary Source Notes

1.5-4 M.A.Badshah and T. Naimei83 2014 no Extrapolated values

2-5 D.H. Beighley84no Productive tillers only

3-4 Chen et al.

85 2007 no

2-4 D. Dickey et.al.86 2015 no At normal planting densities

4-5 R. Dunand and J. Saichuk87 2014 no Primary Tillers

1-3 L. Espino.88 2014 no

1.8-4.8 N.K.Fageria89 2007 no Productive tillers only

15-48 S. Ishikawa90 2005 no Tillering potential

2-30 K. Moldenhauer et al.91 2014 no

2-10 S. Peng et al.92 1993 no Productive tillers only

2.6-9.6 } A.L. Ranawake et al.

93 2013 yes

All tillers

1.7-9.5 Productive tillers only

4-50 S. Yoshida and Y. Hayakawa94 1970 yes Grown in laboratory

1.5-8 L. Zou et al.95 2004 yes

 

83 Badshah, M.A., T. Naimei,, Y. Zou, M. Ibrahim, and K. Wang, 2014, Yield and tillering response of super hybrid rice 

Liangyoupeijiu to tillage and establishment methods, The Crop Journal, 2:79-86.

84 Beighley, D.H., 2010, Growth and Production of Rice, Soils, Encyclopedia of Life Support Systems: Plant Growth and Crop 

Production - Volume II, W.H. Verheye, editor, page 35ff.

85 Chen, L-y., Xiao Y-h., Tang W-b., and Lei D-y., 2007, Practices and Prospects of Super Hybrid Rice Breeding, Rice Science, 

14:71-77.

86 Dickey, D., L. Espino, M. Leinfelder-Miles, C. Mutters, K. Al-Khatib, L. Godfrey, J. Hill, B. Linquist, K. Tumber, and K. 

McKenzie, 2015, Variety Selection and Management, California Rice Production Workshop, v15, University of California 

Rice Production Manual, 3.1-3.26.

87 Dunand, R., and J. Saichuk, 2014, Rice Growth and Development, Louisiana Rice Production Handbook, pp 41-53 

88 Espino, L., 2014, Rice Yield Components, UC Rice Blog: California Rice Production,

89 Fageria, N.K., 2007, Yield Physiology of Rice, Journal of Plant Nutrition 30:843-879.

90 Ishikawa, S. M. Maekawa, T. Arite, K. Onishi, I. Takamure and J. Kyozuka, 2005, Suppression of Tiller Bud Activity in 

Tillering Dwarf Mutants of Rice, Plant Cell Physiology, 46:79-86.

91 Moldenhauer, K., C.E. Wilson, Jr., P. Counce, and J.T Hardke, 2014, Rice Growth and Development, Arkansas Rice 

Production Handbook, pp. 9-20.

92 Peng, S., G.S. Khush and K.G. Cassman, 1993, Evolution of the new plant ideotype for increased yield potential, Breaking the 

yield barrier: Proceedings of a workshop on rice yield potential in favorable environments, IRRI, 29 November 4 December 

1993. International Rice Research Institute, P.O. Box 933, Manila 1099, Philippines, pages 5-20.

93 Ranawake, A.L., U.G.S. Amarasingha, and N. Dahanayake, 2013, Agronomic characters of some traditional rice (Oryza sativa

L.) cultivars in Sri Lanka, Journal of the University of Ruhuna, 1:3-9.

94 Yoshida, S., and Y. Hayakawa, 1970, Effects of Mineral Nutrition on Tillering of Rice, Japanese Society of Soil Science and 

Plant Nutrition, 16:186-191.

95 Zou, L., M.J. Stout and R.T. Dunand, 2004, The effects of feeding by the rice water weevil, Lissorhoptrus oryzophilus

Kuschel, on the growth and yield components of rice, Oryza sativa. Agricultural and Forest Entomology, 47-54.
Tillering Factors for Hybrid Rice

Use or disclosure of information or data Risk Management Agency

contained on this sheet is subject to the Contract Number D16PA00006

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Attachment I

2014 Rice Loss Adjustment Standards Handbook (Updated 

Handbook including Slipsheets)

USDA RMA provides both current and historic loss adjustment materials on its Website 

(http://www.rma.usda.gov/). The 2014 Rice Loss Adjustment Standards Handbook (Updated 

Handbook including Slipsheets) from 

http://www.rma.usda.gov/handbooks/25000/2014/14_25410-2h.pdf is incorporated into the 

report by reference, with agreement of the Government.