IJERD – International Journal of Environmental and Rural Development (2020) 11-2

Research article
erd

Assessing the Yield of a High Yielding Rice Variety, Byaw
Htun, Planted Using the Cut-stem Transplant Method andCultivated in a Deep-water Area, Bago Region, Myanmar
YU MON*
Yezin Agricultural University, Nay Pyi Taw, Myanmar
Email: yumonseven@gmail.com

YOSHINORI YAMAMOTO
Yezin Agricultural University, Nay Pyi Taw, Myanmar

MIE MIE AUNG
Yezin Agricultural University, Nay Pyi Taw, Myanmar
Received 20 January 2020

Accepted 12 December 2020(*Corresponding Author)

Abstract Among the five rice ecosystems in Myanmar, submerged and deep-water areas
occupy 13.5% of the total cultivated area. If flooding occurs, most rice varieties elongate andlay flat after the water recedes. In such a situation, the lodged stems are cut and transplanted
without roots. This cut-stem transplant (CST) method is practiced locally in Ywa Houng
village, Thanatpin Township in the Bago Region, using deep-water rice (DWR) varieties suchas Pawsan and Yoesein in deep-water areas. However, a high yielding variety, Byaw Htun,
is cultivated in the shallow-water areas by using direct seeding (DS) or the normaltransplanting (NT) method. Unusual levels of flooding in 2018 resulted in almost all of the
fields being subject to deeper water conditions than normal in Ywa Houng village. The
highest flood level occurred on 19th July, with a 45cm depth recorded, in what is normally ashallow area (normally less than 25cm depth) and the flood peaked for about 25days. Hence,transplanting of Byaw Htun was delayed until the 10% heading stage in the nursery. Thus,
farmers tested the CST method in place of NT method in Byaw Htun. This study examined
to clarify the growth and yield of CST method for the Byaw Htun variety. Byaw Htun CSTplants exhibit plant growth and yields comparable to those of DS plants. In addition, the yieldof Byaw Htun CST was similar to, or higher than those of Pawsan and Yoesein CST.
However, the harvesting of Byaw Htun CST took place far later than that of DS areas.
Consequently, it was found that CST can be applied for Byaw Htun varieties when the plants
were damaged by flooding, but due to delays in harvesting, the application of this methodshould be considered in relation to any subsequent crops to be cultivated.
Keywords cut-stem transplant, deep water rice, direct seeding, high-yielding rice variety,submerged and deep-water areas

INTRODUCTION
Rice is cultivated on over 7 Million ha in Myanmar, which is more than half of the arable land. There
are five rice ecosystems that have been described for Myanmar. These are lowland rain-fed andirrigated, flooded, deep-water, upland and sea water intrusion areas (MOALI, 2015). Among them,flooded and deep-water areas occupy 13.5% of the total area under rice cultivation (Rice Division,2016). Therefore, construction of flood protection measures, the growing of flood tolerant rice
varieties and/or the development of climate resilient cultural practices are necessary to sustain riceproduction in these areas.
The conventional rice crop establishment methods used throughout the world are direct seeding(DS) and transplanting (NT). In the deep-water areas, dry seeding is fairly common, but transplanting
or double transplanting is practiced in some flooded area in Asia (De Datta, 1981). Likewise, there
is a locally used and adapted method in accord with flooded conditions employed in Ywa HoungⒸ ISERD

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village, Thanatpin Township in the Bago region (Mon et al., 2019a). Ywa Houng is situated at the
Sittaung River basin area, and monsoon flooding occurs frequently. Therefore, a high yielding
variety (HYV) such as Byaw Htun, also a moderate flood tolerant variety, is cultivated in shallowwater areas and photoperiod sensitive deep-water rice varieties (DWR) such as Pawsan and Yoeseinin the deep-water areas.
Normally, DS and NT are undertaken in shallow-water areas. Seeding is done after land
preparation, which starts when the soil moisture content is sufficient for land preparation.
Transplanting in NT method will be carried out when the seedlings are about 35-40 days old.
However, seeding time will vary from field to field and depends on the water availability in thenursery field, adjustments being made to coincide with a suitable depth of water in the fields fortransplantation, and expected moisture availability for a second crop such as legumes, which requiresufficient residual soil moisture. If a second crop will not be cultivated, seeding time will likely be
postponed until the water recedes, to escape the possibility of flood damage.
For deep-water areas, dry seeding is done in April-May after the first flash of monsoon andwater levels start to increase when the seedlings are 1.5 months old. If the plants are not damaged byflooding, NT is followed. However, if flooding occurs, the plant will respond by elongation of thestem and laid flat after the water recedes. In such a case, the lodged stems are cut and transplanted
by using a transplanting fork and the cut-stem transplant method (CST) is practiced (Mon et al.,2019a).
Due to torrential rain in the 2018 monsoon season, abnormal flooding occurred even in
relatively higher-level fields, and transplanting had to be delayed until the growth of Byaw Htun in
the nursery field reached the late booting stage. Hence, farmers tested the CST on this variety in 2018.
Previously CST had only been applied to the DWR varieties such as Pawsan and Yoesein in 2016
and 2017 (Mon et al., 2019a and b), but a HYV, Byaw Htun was planted with the CST method inthat 2018 monsoon season. Hence, this survey was conducted with the following objectives.
OBJECTIVE
The objectives of this study are (1) to clarify the growth and yield performance of CST comparing
with DS planting for Byaw Htun and (2) to compare the yield of CST for Byaw Htun with DWR
yields for Pawsan and Yoesein.
METHODOLOGY
The survey was conducted in Ywa Houng village, Thanatpin Township where the CST method islocally practiced. The location of each harvested field is shown in Fig 1. The water depth wasrecorded at 2 days intervals, starting from 9th June to the 10th November 2018, by setting of threemarking posts at the diagonal of each field. The water depths were measured in 2, 2 and 3 fields forshallow, medium-deep and deep-water areas respectively (Fig 1). Changes of water depth are shownin Fig 2. The water depth was 3, 5 and 10cm in the shallow, medium-deep and deep-water areas at
the beginning of June (9th June) (160 calendar days). The water level gradually increased and thepeak flooding occurred on 17-19th July (198-200 calendar days) with depths of 45, 55 and 85cm
respectively, in each area. Flooding was stagnant for 25 days until 14th August (226 calendar days)
and after that, the water depth gradually decreased and finally receded by the end of October (304
calendar days). The seeding date, transplant date and the harvest date of all varieties are shown in
Table 1. Although the seeding of Byaw Htun CST was 67 days earlier than that of DS, harvesting
was 7 days later. Moreover, the seeding of Byaw Htun CST was 25 days and 18 days later while theharvest date was 26 days and 15 days earlier than those of Pawsan and Yoesein CST. In terms offertilizer application, Byaw Htun DS and CST fields were applied with urea at 62 days after seeding,and 14 days after transplanting (DAT) with the rate of 21 kg ha -1 and 42 kg ha-1, respectively.
Similarly, Pawsan and Yoesein CST were applied with urea at 15 DAT and 16 DAT with the rate of
63 kg ha-1 and 42 kg ha-1, respectively.

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Sampling was done at harvest in farmers’ fields by sampling seven 1m2 plots in each field along
the transverse of the field’s diagonal to determine the yield rates, and hill density was recorded atthese plots. In addition, samplings of 10 hills for each 1m2 plot in the DS fields and 5 hills each for
the CST fields were randomly excavated near each plot, to measure the growth and yield components.

○ Byaw Htun DS● Byaw Htun CST ▲ Pawsan CST■ Yoesein CST

Fig. 1 Map of the sampling plots situated in north west part of Ywa Houng village

Continuous thick line: deep-water area, Dotted line: medium-water area, Continuous thin line: shallow-water area.

Fig. 2 Changes of the water depth at three locations of the paddy fields in Ywa Houng village,
Thanatpin Township, Bago Region, Myanmar (2018)
Table 1 Outline of cultivation methods of Byaw Htun, Pawsan and Yoesein
Seeding

Growth stage
at transplant

Harvestdate

Growthduration(days)*--

20-Nov

116

96

24-Aug10% heading

27-Nov

191

224

129

1-Sep

Tillering

23-Dec

242

103

117

27-AugTillering

12-Dec224

Cultivation
methodMethodDate

Seedling Transplant
Rate
date
(kg/ha) age (days)

DS

WSR

27-Jul

103

-

CST

WSR

20-May103

PawsanCST

DSR

25-AprYoesein

CST

DSR

2-May

Varieties

Byaw
Htun

*: days from seeding to harvest, WSR: Wet seeded rice, DSR: Dry seeded rice, DS: Direct seeding,
CST: Cut-stem transplant

The plant samples were washed for removing the soil and hung for one week. After that, thegrowth parameters and yield components were measured. When measuring the growth parameters in
CST, the two types of plants were observed; the main stem existing, and the main stem died and only
the tillers existing. About 25% of the plant samples in Byaw Htun CST were the main stem died. TheⒸ ISERD

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plants of which the main stem died were skipped to count the number and the length of elongatednodes. For statistical analysis, the average value of each fields resulting from 7 harvested plots was
regarded as one replication. The data were analyzed by using Statistix version 8.0 and mean
separation was done at Least Significant Distance (LSD) at a 5% level.
RESULTS AND DISCUSSION
Comparing the Growth and Yield of CST and DS in Byaw Htun
The internode elongation patterns of CST and DS in Byaw Htun are shown in Fig 3 (A). In both CST
and DS, the basal internodes (1st to 3rd) were almost the same length and after that there was anincrease from 4th internode to succeeding nodes. However, the basal internodes’ lengths of DS wereshorter than comparable nodes of CST plant. It showed that a DS plant was not affected by flooding
at the vegetative stage. Because, the DS fields were located on the river bank, drainage of excesswater was easier (Fig 1) and seeding was done after flooding.
The growth parameters of Byaw Htun DS and CST are shown in Table 2. The plant length, culm
length, panicle length, the number of elongated nodes and the number of roots per hill of CST weresimilar and not significantly (p<0.05) different than those for DS plants. All the shoot dry weight (g)showed no significant difference except the shoot dry weight per stem. Yields and yield components
are shown in Table 3. The hill density of CST (29.2) was about half of DS (63.6). However, thenumber of panicles per hill was higher in CST. The number of grains per panicle was not statisticallydifferent between the two methods. In addition, filled grain (%) and 100 grains weight were notsignificantly different, as well. Finally, the yield (g/m 2) of CST (412.7 g/m2) was not significantly
different from that of DS (400.3 g/m2). Although, the grain yield of Pawsan DS was lower than thatof CST in Ywa Houng village (Mon et al., 2019b), similar yield in Byaw Htun DS and CST were
due to the field location and cultivated condition. DS in this experiment was cultivated in the shallow
area, not affected by flooding and being able to apply fertilizer during the plant development.
Therefore, it could produce the plant growth and yield comparable to that of CST.
Internode number*

12

(A)

8
4

0
0

10

20

30

40

50

Internode number*

Length of elongated internode in Byaw Htun (cm)
DS
CST

12

(B)

8
4
0

0

10

20

30

40

50

Length of elongated internodes (cm)
Byaw Htun
PawsanYoeseinFig 3 Internode length of each elongated internodes of DS and CST in Byaw Htun (A)and CST in Byaw Htun, Pawsan and Yoesein (B)* Node number count from the stem base

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Despite the yields of these two methods were similar, the growth duration of CST was 75 days
longer than that of DS (Table 1). Because, Byaw Htun was photoperiod insensitive HYV andmaturity was depended on the growth duration. After transplantation, some of the main stem diedand the tillers were produced from the remaining nodes of the stem. CST plants reset the growthfrom the tillering stage although it was transplanted at 10% heading stage. Therefore, the growthduration was longer than that of DS. In addition, CST needed high cultivation cost especiallytransplantation cost than that of DS. Therefore, in consideration of the cost and labor for the CSTtransplantation and the effective use of the paddy field, CST in Byaw Htun would not be applicablein the area where the flooding is not use to occur.
Table 2 The plant growth parameters of Byaw Htun cultivated with direct seeding andcut-stem transplant method
Cultivation
Plant
methodlength(cm)DS
CST

108.5a98.7aCulm
Length
(cm)
84.0a
76.6a

PanicleLength (cm)

No. of
nodes

24.5a
21.4a

7.2a
6.9a

Shoot dry weight (g)No. of roots
per hill(/stem) (/hill)(/m2)
252.1a474.9a

6.9a
4.6b

28.6a
19.1a

1038.1a816.2a*DS: Direct seeding, CST: Cut-stem transplant, Values followed by the same letter within each column do not different at
p<0.05 by using statistix version 8.0

Table 3 Yields and yield components of Byaw Htun cultivated with direct seeding andcut-stem transplant method
VarietyHilldensityNo. of panicle
per hill

No. of grains
per panicle

Filled grain(%)

100 grains
weight (g)Yield(g/m2)

DS
CST

63.6
29.2

2.8
6.7

166.2
138.6

63.78
72.06

2.34
2.26

400.3
412.7

*DS: Direct seeding, CST: Cut-stem transplant, Values followed by the same letter within each column do notdifferent at p<0.05 by using Statistix version 8.0.

Comparing the Growth and Yield of Byaw Htun CST with those of Pawsan and Yoesein
The pattern of internode elongation among CST is shown in Fig 3 (B). The internode elongation
patterns of Byaw Htun, Pawsan and Yoesein CST were similar in that the internode length from the
1st to 3rd nodes were short and then the length gradually increased from the 4th to the higher nodes. It
showed all CST developed under similar field condition. However, the number of elongated nodes
in Byaw Htun (6.9 nodes) was less than those of Pawsan (8.2 nodes) and Yoesein (8.7 nodes) and it
could depend on the plant type. Byaw Htun was a photoperiod insensitive HYV while the other 2varieties (Pawsan and Yoesein) were photoperiod sensitive DWR. There was a correlation between
the number of elongated internodes and the vegetative growth period in DWR and local rice varieties,
while no correlation was found in the semi-dwarf cultivar (Hamamura, 1978). Hence, the number of
elongated nodes of Byaw Htun might be expected to be less than those of Pawsan and Yoesein. In
addition, the younger seedling age and the shallower field condition in Byaw Htun causes a smaller
number of elongated nodes than DWRs.
The growth parameters of Byaw Htun and Pawsan are compared in Table 4. Among the plants
following CST method, plant length, culm length and number of nodes of Byaw Htun were the lowest
while those of Pawsan and Yoesein showed a very similar value. However, the panicle length (cm)of Byaw Htun was not significantly different from those of Pawsan. The number of roots per hill of
Byaw Htun was the lowest, although it was not significantly different from Pawsan. The shoot dry
weight per stem and per hill of Byaw Htun were significantly less than those of Pawsan, though theshoot dry weigh per m2 of Byaw Htun was not significantly different due to higher hill density in
Byaw Htun. The yields and yield components are shown in Table 5. Among the varieties, the hill
density of Byaw Htun was the highest followed by Yoesein and Pawsan. In contrast to that, thenumber of panicles per hill of Byaw Htun was significantly lower than other varieties. Whereas, theⒸ ISERD

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number of grains per panicle of Byaw Htun was statistically higher than that of Pawsan. Filled grain(%) of Byaw Htun and Yoesein was higher than that of Pawsan. Because the grain filling period of
Byaw Htun was earlier than those of Pawsan and Yoesein by 26 days and 15 days, the availability ofsoil moisture for grain filling of Byaw Htun was higher than those of Pawsan and Yoesein. However,the 100 grains weight of Byaw Htun was the lowest due to small grain size. Yields (g/m 2) of Byaw
Htun (412.7) was the highest, followed by Yoesein (291.9) and Pawsan (286.7) although this did not
represent a significant difference between Byaw Htun and Pawsan. Because of the earlier maturity
in Byaw Htun, the moisture availability at grain filling would be higher than those of Pawsan and
Yoesein. In some years, the rainfall finishes early and moisture deficit affecting the grain yield occur
in the late harvested varieties especially Pawsan. Under such condition, Byaw Htun would produce
significantly higher yield than that of Pawsan particularly in Ywa Houng village where no irrigatedwater was available for grain filling. Therefore, Byaw Htun can be followed with CST in the deepwater area if the flood damage occurred.
Table 4 The growth parameters of Byaw Htun, Pawsan and Yoesein cultivated with
cut-stem transplant method
Variety

Plant

Culm

Paniclelength (cm) Length (cm) Length (cm)

No. ofnodes

No. ofShoot dry weight (g)roots per(/stem) (/hill)
(/m2)
hill

Byaw Htun

98.1b

76.6b

21.5a

6.9b

474.9a

4.6b

28.6b

816.1aPawsan141.5a117.4a

24.1a

8.2a

561.5a

7.0a

66.1a

867.3aYoesein*

152.5

127.5

24.2

8.7

566.9

5.9

41.6

842.3

Analysis was done for Byaw Htun and Pawsan only by using statistix version 8.0, * No replication. value followed by thesame letter within each column do not different at p< 0.05.

Table 5 Yields and yield components of Byaw Htun, Pawsan and Yoesein cultivated with
cut-stem transplant method

Byaw Htun

Hilldensity
27.1a

No. of panicles
per hill
6.7b

No. of grains
per panicle
138.6aFilled grain(%)
72.06a100 grain
weight (g)
2.26b

Yield
(g/m2)
412.7aPawsan

13.4b

11.6a

94.3b

61.17b3.24a286.7aYoesein*

20.4

6.7

105.2

69.05

2.97

291.9

Variety

Analysis was done for Byaw Htun and Pawsan only by using statistix version 8.0, * No replication, value followedby the same letter within each column do not different at p<0.05

CONCLUSION
Although CST in Byaw Htun can be transplanted, it took longer growth duration than that of DS.
Therefore, CST in Byaw Htun should not be followed in the area where no flood damage occurs andthe second crop such as legume will be cultivated after rice harvest. However, Byaw Htun CST
produce the yield comparable to those of Pawsan and Yoesein CST. Moreover, it can harvest earlier
than those of Pawsan and Yoesein. Therefore, CST in Byaw Htun could be practiced in the area
where the flood damage occurred.
ACKNOWLEDGEMENTS
This research was financially supported by the YAU-JICA Technical Cooperation Project.

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REFERENCES
De Datta, S.K. 1981. Principles and practices of rice production. John Wiley & Sons, Inc. UK.
Hamamura, K. 1978. Relation between number of elongated internodes and days from seeding to heading infloating and non-floating rice varieties. Jpn. J. Trop. Agr., 22 (2),77-81.
MOALI (Ministry of Agriculture, Livestock and Irrigation). 2015. Myanmar agriculture at a glance.
Department of Agricultural Planning, Ministry of Agriculture, Livestock and Irrigation, Myanmar.
Mon, Y., Yamamoto, Y. and Aung, M.M. 2019a. The special rice transplanting method, cut stem transplant,(A Sit Phyat) practiced in deep water areas of Bago Region in Myanmar. Trop. Agr. Develop., 63 (1), 38-46.
Mon, Y., Yamamoto, Y. and Aung, M.M. 2019b. The growth and yield of cut-stem transplant (A Sit Phyat)
rice practiced in deep-water area of Bago Region, Myanmar. Trop. Agr. Develop., 63 (4), 176-185.
Rice Division. 2016. Annual report for rice production in 2015-2016. Department of Agriculture, Ministry ofAgriculture, Livestock and Irrigation, Myanmar.

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