Genetic variation in heading dates and phenological parameters of Myanmar rice

Figures & data

Table 1. List of plant materials used in this study.

Variety Name (Accession no. in DAR)	Abbreviation	Conventional classification
Paw San Hmwe (002082)	PSH	Photoperiod sensitive
Nga Kywe Gyi (002546)	NKG	Photoperiod sensitive
Inn Ma Yebaw	IMY	Photoperiod sensitive
Nga Kywe Taung Pyan(002054)	NKTP	Photoperiod sensitive
Mote Soe Ma Kyway Kyay (R20783)	MSMKK	Intermediate photoperiod sensitive
Shwe Bo Paw San	SBPS	Photoperiod insensitive
IR24	IR24	Photoperiod insensitive
Sin Thu Kha	STK	Photoperiod insensitive

Figure 1. Definitions of the measures for characterization of heading date in this study. The details are described in the materials and methods section.

Figure 2. Heading date and days to heading (DTH) of eight tested varieties sown on different dates throughout the year. The numbers indicate the varieties’ DTH. The months where the shortest DTH was detected are underlined and in bold text.

Table 2. Days to heading under short-day treatment during the dry season from December 2019 to April 2020.

Variety	Days to Heading after short-day treatment
	1^st sowing	2^nd sowing	3^rd sowing
	(Jan 30, 2020)	(Feb 6, 2020)	(Feb 13, 2020)	Average
PSH	34	32	31	33
NKG	34	33	32	33
IMY	26	25	23	25
NKTP	36	33	31	33

Table 3. Days to heading under short-day treatment in the 2020 monsoon season from July to November 2020.

Variety	Days to Heading after short-day treatment
	1^st sowing (Sep 5, 2020)	2^nd sowing (Sep 12, 2020)	3^rd sowing (Sep 19, 2020)	4^th sowing (Sep 28, 2020)	Average
PSH	30	29	29	26	29
IMY	28	31	28	26	28

Figure 3. Critical day length of eight tested varieties. The grey curves indicate the day length at Nay Pyi Taw from February 2019 to April 2020. Small dots were plot of the varities sown at each month. The dots are drawn at the date for 30 days before heading (DBH₃₀) in a horizontal axis and day length at date for 30 days before heading (DL₃₀) in a vertical axis. The longest DL₃₀ are defined as the critical day lengths for each variety (red line).

Figure 4. DVI models of the April to July sowing times constructed using the NK05 and CDL models. (a,b) regression of the predicted DTH by the observed DTH to show the accuracy of prediction in the eight varieties in the NK05 (a) and CDL (b) models. (c) The adjusted coefficient of the determinant (R²) in each tested variety on the short-term DVI models. (d,e) R² in each tested variety on the long-term DVI models using data of sowing from February 2019 to January 2020 (d) and data of sowing from February to November 2019. Grey and black bars represent the NK05 and CDL models, respectively.

Table 4. The adjusted coefficient of determinant R² of the predicted DTH regressed by the observed DTH in four month sowing period throughout a year.

Sowing time	PSH			NKG			IMY		NKTP		MSMKK		SBPS		IR24		STK
	NK05	CDL		NK05	CDL		NK05	CDL	NK05	CDL	NK05	CDL	NK05	CDL	NK05	CDL	NK05	CDL
Feb. to May	0.996	0.995		0.995	0.994		0.144	0.995	0.183	0.980	0.955	0.925	-0.058	-0.054	0.559	0.736	0.639	0.522
Mar. to Jun.	0.995	0.996		0.973	0.980		0.995	0.996	0.781	0.747	0.088	0.967	0.523	0.435	0.543	0.826	0.709	0.641
Apr. to Jul.	0.993	0.995		0.977	0.979		0.999	0.999	0.975	0.980	0.984	0.975	0.966	0.966	0.700	0.848	0.910	0.903
May to Aug.	0.995	0.995		0.973	0.968		0.998	0.999	0.965	0.980	0.982	0.904	0.871	0.883	-0.037	0.002	0.549	0.467
Jun. to Sep.	0.988	0.988		0.949	0.953		0.997	0.996	0.935	0.894	0.907	0.921	0.610	0.652	0.035	−0.043	0.064	-0.020
Jul. to Oct.	0.901	0.958		0.947	0.944		0.987	0.954	0.474	0.492	0.582	0.543	0.791	0.798	0.697	0.694	0.800	0.846
Aug. to Nov.	0.876	0.932		0.897	0.883		0.951	0.897	0.795	0.778	0.110	0.150	0.738	0.748	0.663	0.585	0.671	0.851
Sep. to Dec.	0.635	0.597		0.834	0.826		0.576	0.561	0.651	0.628	0.254	0.245	0.486	0.481	0.267	0.287	0.593	0.552
Oct. to Jan.	0.443	0.441		0.548	0.463		0.402	0.455	0.444	0.291	-0.071	−0.070	0.027	0.023	-0.021	−0.011	0.079	0.044

Improved R² values more than 0.1 are marked in underline.

Data availability statement

The data used to support the findings of this study have been included in this article.