The HWC-line of rice showed wide compatibility with both indica and japonica cultivars, tall culm length, long and slender grain shape. For QTL analysis, two F2 populations were derived from the crosses between the HWC-line and each of two Korean variety, Dasanbyeo (Korean Tongil-type cultivar) and Hwacheongbyeo (temperate japonica cultivar), respectively. A total of 190 F2 plants were evaluated in each of two F2 populations. Eight agronomic characters were measured for QTL analysis in F2 populations and parents. Two molecular linkage maps were constructed. In the F2 population from cross between HWC-line / Dasanbyeo (HD) cross, 93 STS markers and 13 SSR markers were mapped on 12 chromosomes, covering a total length of 1942.6 cM, with an average distance of 18.33cM between adjacent markers. In the F2 population from HWC-line / Hwacheongbyeo (HH) cross, 28 STS markers, 29 SSR markers and 1 FNP marker were mapped on 11 chromosomes, spanning a total length of 925.53cM, with an average distance of 15.96cM between adjacent markers. In the F2 population from HD cross, 16 M-QTLs and 1 E-QTL were detected for culm length, spikelets per panicle, spikelet fertility, grain length, grain width, grain shape and 100 grains weight. 7 QTLs of spikelet fertility, grain length, grain width and grain shape were newly identified in this study. In the F2 population from HH cross, 15 M-QTLs were detected for culm length, panicle length, spikelet fertility, grain length, grain width, grain shape and 100 grains weight. 6 QTLs of culm length, grain length, grain width and grain shape were newly identified in this study. The QTLs identified in this study would provide basic information on putative functional genes related agronomic characters and facilitate breed new rice cultivar.

The earth has been facing a rapid warming during past several decades. To figure out the impact of high temperature on agronomic performance of rice especially on yield, we cultivated 89 rice varieties of various origin in Suwon Korea, Shanghai China and IRRI Philippines(Wet season and Dry season). Days to heading, culm length, panicle length, panicle number, spikelet number, spikelet fertility, grain weight and grain yield were comparatively investigated. Overall grain yield displayed significantly lower values in Shanghai and IRRI(wet and dry) compared with in Suwon. Meanwhile minimum values were much lower in Shanghai and IRRI than in Suwon. However, some varieties such as Keunseom, Taichung178 showed similar performance for grain yield in both Suwon and IRRI(wet season), and some varieties such as Hangangchal, Dasan showed similar performance for grain yield in Suwon, Shanghai and IRRI(wet season), Nampung showed very high yield in Suwon comparing to other two locations. For most varieties, grain yield was the highest in Suwon and followed by in Shanghai and at IRRI(wet season). However, in dry season at IRRI, yield trend was quite different from the expectation. Further studies are in progress to find out the genotype by environment interactions in order to obtain basic information for breeding high temperature tolerant rice.