Analysis Of QTL For Heat Tolerance At Flowering Stage And Main Agronomic Traits In Rice

Along with the advancement of industrialization and the development of human society, a lot of greenhouse gases are put into the air, which causes global warming and frequent climate changes widely. Extreme heat in summer appears more and often, which has a great impact on the rice production, especially for the yield and quality. So it is urgent to conduct the research and breeding of heat resistance tolerance in rice.In this research, rice ZS97 B and upland rice IRAT109 were selected as parents to build the RILs population of 137 lines, and QTLs controlling the heat tolerance(HTI, which is the raio of the seed setting rate of normal condition to that under heat stress condition) and main ten agronomic traits including DSF, PH, EPN, PL, GP, SP, SSR, SD, TGW and YP of RILs were analyzed with the combination of the genetic linkage map of rice. Furthermore, the test-cross population derived from RIL lines and Guangzhan63-4S was constructed to assess the application of the RIL lines in the development of heat-tolerant, strong-heterosis hybrids. The main results are as following: 1、A genetic linkage map consisting of 210 SSR markers, was constructed using the RILs population. It covered 1747.7 cM in the whole genome. An average interal was 8.32 cM between two markers. 2、4 main effect QTLs(qHTI-6, qHTI-7, qHTI-9, qHTI-12) were detected in three years which controlled heat tolerance during flowering time. The LOD values ranged from 1.6-2.3, and PVE ranged from 6.79% to 8.40%. 12 pairs of epistatic QTLs were found, whose LOD values ranged from 4.22-6.65, and PVE were 15.25% to 68.21%.3、51 QTLs controlling main 10 agronomic traits were detected in 2012-2014, in which 8 QTLs for PL and SD respectively, 7 QTLs for SSR, 5 QTLs for SDF, GP and TGW respectively, 4 QTLs for PH and YP respectively, 3 QTLs for EPN, and 2 QTLs for SP. Some QTLs such as qGP1-1,qGP3-1 and qPH10-1 were detected in 2012-2014 consecutively. 4、The comparison between RILs and test-cross lines derived from RILs line and Guangzhan63-4S showed that about 40% of test-cross lines had the superior heat tolerance to corresponding RIL lines, and most of test-cross lines appeared the strong-heterosis on these traits such as PH, GP, SP, SD and YP in comparison with RIL lines. These results have provided some important guidelines for the genetic improvement of heat tolerance of rice and the development of strong-heterosis hybrids with multi-resistance, high-yield and high-quality.