Items of Interest in Seed – Winter 2024 (December 2023 – February 2024) 

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USDA Seed Regulatory and Testing Division

Winter 2024 

TABLE OF CONTENTS

• Recent Activities........................................1

• State Seed Regulators Quarterly Meeting.......1

• Detecting Endosperm.............. ...................2

• Internet Seed Sales and the FSA..................2

• Differentiating Kentucky 31 Variety of Tall 

Fescue.....................................................3

• OECD TWG Meeting..................................4

• Calendar of Events ....................................4

RECENT ACTIVITIES 

SRTD HOSTS WEBINAR TRAINING 

In January, Botanist Kathryn McGinnis presented 

for the AOSA/SCST Teaching and Training 

Committee on seed structure, endosperm 

development, and identifying fescue and ryegrass

species. These webinars help promote uniformity 

among seed testing laboratories and are available 

here: AOSA / SCST Teaching and Training – 

Analyzeseeds. 

AOSA/SCST MERGER UPDATE

In February, SRTD Laboratory Supervisor, Todd 

Erickson, participated in the presentation of a 

recommended plan of action for the merger of the 

Association of Official Seed Analysts (AOSA) and 

the Society of Commercial Seed Technologists 

(SCST). The presentation was given by the 

merger working group to the Executive Boards of 

both organizations. SRTD works closely with both 

organizations to ensure uniformity of seed testing 

among U.S. laboratories and to strengthen 

enforcement of State and Federal seed laws. The 

objective of this merger is to reduce costs and 

redundancy in the seed testing industry. In the 

next few months, the proposal will be presented to 

the membership for comments. 

SRTD ASSISTS WITH GUIDANCE ON HEMP 

LABELING 

Throughout this quarter, SRTD staff worked with 

AMS Specialty Crops Program to review the 

production of a hemp seed labeling educational 

presentation. SRTD consulted on properly 

labeling hemp seed under the Federal Seed Act. 

The presentations are part of an outreach project 

for USDA Hemp Licensees regarding the purpose 

of the Federal Seed Act, the requirements for 

hemp seed labels, and information about certified 

hemp seed. 

STATE SEED REGULATORS

QUARTERLY MEETING 

The Seed Regulatory and Testing Division (SRTD) 

conducts regional quarterly virtual meetings with 

State Seed Control Officials (SCO). The goal of 

the meetings is to promote better communication 

and working relationships with SCOs and discuss 

current industry issues. Topics from the most 

recent meetings included: trueness-to-variety 

trials, seed labeling for seeds one pound or less, 

ladino clover kind name violations, and an update 

on the USDA Seed Liaison Initiative priorities. 

State regulator quarterly meetings are intended to 

be comprehensive where SCOs can have all their 

questions answered. To this effect, SRTD ensures 

that all relevant staff are available. These staff 

members include the SRTD Director, Laboratory 

Supervisor, OECD Seed Schemes Program 

Manager, and regulatory staff. 

For more information regarding this article, contact 

Seed Marketing Specialist Kevin Robinson at (704)

810-7264; kevin.robinson2@usda.gov. 

ITEMS OF INTEREST IN SEED
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DETECTING ENDOSPERM

In grass seeds, the endosperm is the nutritive 

tissue surrounding the embryo of a seed derived 

from the fusion of a sperm cell with the polar nuclei 

of the embryo sac. Endosperm plays an important 

role in supporting embryonic growth by supplying 

nutrients, protecting the embryo, and controlling 

embryo growth by acting as a mechanical barrier 

during seed development and germination.

There are three ways in which a seed analyst can 

determine if a grass seed has enough endosperm 

to be considered pure seed. 

• The first method is to use the blowing point 

of the species to separate the seed via the 

general seed blower. The uniform blowing 

procedure is used for separation of pure 

seed and inert matter in the following: 

Kentucky bluegrass (Poa pratensis), 

Canada bluegrass (P. compressa), rough 

bluegrass (P. trivialis), weeping alkaligrass 

(Puccinellia distans), ‘Pensacola’ variety of 

bahiagrass (Paspalum notatum), 

orchardgrass (Dactylis glomerata), blue 

grama (Bouteloua gracilis), and side-oats 

grama (B. curtipedula). No further 

examination of the endosperm is 

necessary if the blowing point is used. 

• The second method is to examine the 

seeds over light. Endosperm is thicker and 

darker than the lemma and palea of a 

grass seed. When it is examined over 

light, a seed without endosperm will 

appear lighter and more transparent than 

a seed that contains an endosperm. 

• The third method is to apply slight pressure 

to the seed with forceps. If a floret does not 

contain an endosperm, it will usually fold or 

crumple like paper, whereas an 

endosperm will feel firm inside the floret.

Structures that are not specifically described as 

part of the pure seed unit (PSU) shall be removed 

and classified as inert matter. The PSU numbers 

given for species in Table 2A correspond to the 

PSU numbers in Table 3A. It is important to double 

check the rules for any special PSU definitions in 

different species to get the most accurate results 

possible. For some seeds to be considered pure, 

such as Festuca and Lolium species, they must 

contain an endosperm that is at least one third the 

length of the palea. If it is smaller than that, it is not 

considered pure seed. Florets containing flower 

parts are considered inert matter and not pure 

seed. Identifying flower parts can be difficult 

because they look very similar to endosperm

when examined over light, but there are a few 

identifying characteristics. Flower parts include 

stamens that look like fingers or prongs broken up 

vertically. They also easily break up when gently 

poked with forceps, whereas an endosperm will 

remain firm. Knowing how to identify the 

differences between flower parts and sufficient 

endosperm is crucial for getting accurate purity 

test results. 

Left: Floret with endosperm that is less than one third

the length of the palea. Center: Floret with sufficient 

endosperm. Right: Floret with flower parts and lacking 

endosperm. (D.J. Lionakis Meyer CDFA/PPDC 2007)

For more information regarding this article, contact 

Botanist Kathryn McGinnis at (704) 810-8872; 

kathryn.mcginnis@usda.gov. 

INTERNET SEED SALES AND THE 

FEDERAL SEED ACT

SRTD is strengthening internet monitoring on 

seeds sold over the internet. The Division is taking 

appropriate actions on quality and advertisement 

violations regarding this issue. Seed internet sales 

are subject to the same labeling and advertising 

requirements of the Federal Seed Act as any other 

seed shipped interstate commerce. Information on 

the Federal Seed Act regulations can be found

here: www.ams.usda.gov/rules-regulations/fsa

For more information regarding this article, contact 

Seed Marketing Specialist Rodney McNeace at 

(704) 810-8879; rodneyb.mcneace@usda.gov.
Items of Interest in Seed – Winter 2024 (December 2023 – February 2024) 

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DIFFERENTIATING KENTUCKY 31 

VARIETY OF TALL FESCUE 

In 2017, SRTD and cooperating State regulatory 

agencies began noticing high contamination 

levels in seed lots of the Kentucky 31 variety of tall 

fescue. Shortly after, several seed industry 

organizations and seed companies approached 

SRTD to request assistance with the issue. SRTD 

noted that mislabeling for the variety was more 

than 30%, much higher than the 3-6% the agency 

was accustomed to seeing. Contaminated seed 

lots were found at all levels of production and 

distribution within the industry indicating a 

systemic problem. This unexpected issue 

highlighted the lack of testing options available to 

quickly differentiate the Kentucky 31 variety from 

other varieties of tall fescue.

Distinguishing the Kentucky 31 variety from other 

tall fescue varieties based on seed morphological 

characteristics is challenging. The most common 

method for identifying the variety is a field growout test. While highly accurate in varietal 

determination, the field test can take six to eight 

months to complete. During that time, the plants 

may face several hardships from unfavorable 

weather, pests, and disease.

SRTD Plant Physiologist, Dr. Yujia Wu, led the 

development of a method using polyacrylamide 

isoelectric focusing electrophoresis (PA-IEF) to 

verify the Kentucky 31 variety of tall fescue. The 

method highlights a unique 4-band pattern found 

only in Kentucky 31 when compared to other tall 

fescue varieties. The duration of the method is 

approximately 4 weeks, making it more efficient 

than a field grow-out test. 

Over a two-year period, field grow-out tests and 

the PA-IEF tests were compared for 276 tall 

fescue samples. The results between the two test 

methods were consistent. Approximately 30% of 

samples were found to be off-types in the PA-IEF 

test and 31% by field grow-out test.

To further validate the PA-IEF method, Dr. Wu 

worked with analysts in four State seed 

laboratories. Statistical data analysis indicated 

that the method is repeatable and reproducible. In 

April of 2023, the method was published in the 

International Seed Testing Associations online 

journal. Dr. Wu then presented at the 2023 

American Seed Trade Association Annual 

Meeting to show the benefits of the PA-IEF 

method of lower over-all costs and faster testing 

time when compared to a field grow-out test. 

By using the PA-IEF method, SRTD tested 

samples submitted by State regulators and 

industry stakeholders who voluntarily submitted 

their seed lots that showed signs of tall fescue 

variety contamination. This combined effort

reduced contamination in domestically traded 

Kentucky 31 grass seed lots from 30% to back to 

the historical average of 3%. 

IEF gel patterns of Tall Fescue varieties, the arrows 

indicate the unique 4-band pattern of Kentucky 31

variety. (Yujia Wu AMS SRTD 2023) 

For more information regarding this article, contact 

Plant Physiologist Yujia Wu at (704) 810-7267; 

yujia.wu@usda.gov. 

OECD TECHNICAL WORKING 

GROUP MEETING 

On January 29 - February 2, Dr. Steve Malone 

represented the U.S. at the Technical Working 

Group (TWG) meeting of the Organization for 

Economic Cooperation & Development (OECD) 

Seed Schemes in Livingstone, Zambia. The 

week began with a workshop on the impact of the 

OECD Seed Schemes on improved availability of 

high-quality seed across Africa, especially in 

those countries that have joined the Seed Stingray Falcon IV Pedigree Kentucky 31
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Schemes in the past decade. Ad Hoc Working 

Groups discussed the Digital Hub development

which will help verify seed lots and share

information between participating countries. They 

also discussed a proposal to change rules 

concerning labelling of small packages of seed 

(less than 2Kg). The outcomes of those 

discussions were forwarded to the TWG for further 

consideration. The technical field trip took 

delegates to a hybrid maize production location 

and post-control plots for maize and soybean. 

The TWG agreed to forward several rules and 

procedural proposals for approval at the annual 

meeting later in the year including clarification of 

guidelines for Multiplication Abroad Agreements, 

next phases of the Digital Hub, the list of eligible 

varieties, and updated taxonomy within the 

Sorghum and Pearl Millet Seed Scheme. The 

TWG recommended that the annual meeting not 

adopt the proposed changes to small packages, 

and to move forward with further exploration of 

rearrangement of the Schemes to possibly split 

the Grass & Legume Seed Scheme into a Grass 

Scheme, and separate Schemes for small-seeded 

versus large-seeded legumes. Similar 

considerations may be considered regarding the 

Crucifer and Other Oil & Fiber Seed Scheme. 

The Annual Meeting of the OECD Seed Schemes 

is scheduled for June 10-14 in Nice, France. 

For more information regarding this article, contact 

OECD Program Manager Steve Malone at (704)

810-8888; steve.malone@usda.gov. 

CALENDAR OF EVENTS 

• Association of Official Seed Certifying Agencies 

Southern Region Meeting 

Cary, NC; March 26-27, 2024 

• Association of Official Seed Certifying Agencies

North and West Regional Meeting 

Custer, SD; April 8-10, 2024

• Association of Official Seed Analysts/ Society of 

Commercial Seed Technologist Annual Meeting 

Rapid City, SD; June 1-6, 2024 

• Organization for Economic Cooperation and 

Development Seed Schemes Annual Meeting 

 Nice, France; June 10-14, 2024

• Association of Official Seed Certifying Agencies 

Annual Meeting 

Destin, FL; June 16-19, 2024

• International Seed Testing Association Annual 

Meeting 

Cambridge, UK, July 1-4, 2024 

• The Association of American Seed Control Official

Annual Meeting 

Salt Lake City, UT; July 14-20, 2024

• Seed Regulatory and Testing Division Seed 

School 

Gastonia, NC; August 2024 

• American Seed Trade Association Forage, Turf 

and Conservation Seed Conference 

Kansas City, MO; October 30, 2024

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