Breeding efforts to mitigate damage by heat stress to spikelet sterility and grain quality

Figures & data

Table 1. Overlapped or closely linked QTLs for heat tolerance identified in different populations.

Chr	QTL	Marker	Position (Mb)	LOD	Ad^a	R^2 (%)^b	Donor	References
1	qHTSF1.2	id1013342	20.80–28.34	5.16	4.10	13.30	Giza178	Ye et al. (2015a)
1	qHTSF1.2	id1016436	26.91–33.67	2.94	16.80	14.60	Giza178	Ye et al. (2015a)
1	qtl_1.1	B1065E10	38.35	6.20	−0.173	17.60	Bala	Jagadish et al. (2010)
1	qHTSF1.1	id1023892	39.55	4.63	5.66	12.60	N22	Ye et al. (2012)
3	qtl_3.4	R1618	30.67	3.30	−0.136	11.40	Bala	Jagadish et al. (2010)
3	qHt3	RM570-RM148	35.59–35.83	13.60	−5.20	11.40	T226	Chen et al. (2008)
4	SSPc4	RM5687-RM471	15.74–18.82	15.43	9.32	25.82	996	Xiao et al. (2011)
4	qtl_4.1	C734	16.86	4.30	−0.079	11.40	Bala	Jagadish et al. (2010)
4	qHTSF4.1	id4005120	17.69	6.66	0.81	17.60	N22	Ye et al. (2012)
4	qHTSF4.1	id4005120	16.51–20.93	4.06	16.50	19.50	Giza178	Ye et al. (2015a)
4	qHTSF4.1	4,285,667	17.16–18.98	5.00	11.70	13.00	MY23 or Giza178	Ye et al. (2015a)
4	qss-4	RM5749–5,586	19.73–19.95	4.60	−20.10	18.60	GJ9	Zhao et al. (2006)
5	qss-5	RM153–13	0.19	5.30	−21.30	19.70	GJ9	Zhao et al. (2006)
5	qHTH5	RM592-RM7921	2.79–3.01	8.90	11.30	19.40	O. rufipogon	Cao et al. (2015)
5	qhts-5	RM405–274	3.07–26.85	4.55	0.66	10.70	ZYZ8	Zhang et al. (2008)
5	qSF5	RM430-RM440	18.69–19.12	4.23	−4.16	13.55	Xiushui9	Cheng et al. (2012)
6	qHTSF6.1	6,053,591	6.37–8.19	4.45	6.70	11.60	Giza178	Ye et al. (2015a)
6	qHTSF6.1	id6007495	7.15–15.47	4.81	17.20	20.60	Giza178	Ye et al. (2015a)
11	qHTSF11.3	10,923,499	3.02–3.80	5.38	8.30	13.90	Giza178	Ye et al. (2015a)
11	qhr11–2	RG118-Adh	4.41	10.65	10.37	22.81	IR64	Cao et al. (2003)
11	qHTSF11.2	id11003281	6.58–11.00	3.43	14.20	15.20	Giza178	Ye et al. (2015a)

^a Additive effect,.

^b QTLs with R² > 10% are selected.

Figure 1. Flowering pattern of Kosihikari and alien introgression lines of O. officinalis. Opened spikelet number per panicle was counted every 20 min. Closed rhomboids, gray squares, gray triangles, and open circles indicate opened spikelet number per panicle of EMF20, EMF44, EMF71, and Koshihikari, respectively.

Table 2. Spikelet sterility (%) of Nanjing11, Nanjing11 + qEMF3, and popular cultivars in tropics in control and heat treatment.

Rank	Varieties	Control (30 °C)^b	Heat (38 °C)^b
	Nanjing11^a	1.3 ± 2.8	33.9 ± 14.8
	Nanjing11 + qEMF3 ^a	4.0 ± 4.0	30.3 ± 4.8
Tolerant	BR11	8.3 ± 1.6	23.1 ± 18.9
	Sahel 108	5.7 ± 5.1	24.5 ± 17.7
Moderately tolerant	TDK1	3.3 ± 3.2	38.2 ± 21.6
Susceptible	Caiapo	4.7 ± 3.8	85.8 ± 13.6
	Pusa Basmati	12.1 ± 6.9	88.8 ± 10.8

Notes. The following numbers of spikelets were exposed under control and heat conditions: 264 and 107 in Nanjing11, 238 and 131 in Nanjing11 + qEMF3, 136 and 152 in BR11, 210 and 403 in Sahel 108, 113 and 260 in TDK1, 248 and 340 in Caiapo, and 321 and 255 in Pusa Basmati, respectively. The following numbers of panicles were exposed under control and heat conditions: 4 and 7 in BR11, 9 and 17 in Sahel 108, 5 and 10 in TDK1, 6 and 14 in Caiapo, and 9 and 10 in Pusa Basmati, respectively.

Values are the mean ± S.D. (n ≧ 4).

^a These data are referred from Hirabayashi et al. (2015).

^b Method for heat tolerance test is the same as Experimental 1 of Shi et al. (2015).

Figure 2. Phenotype of WBCG. A: Overview of whole grain, B: Median transversal section of WBCG, C: Magnified view at chalky part. The outermost position indicated by white arrow is aleurone layers at dorsal side of the grain. The phenotype of starchy endosperm adjacent to dorsal aleurone layers is called as white-back chalkiness (red arrow).

Table 3. QTLs associated with tolerance of WBCG.