Germplasm Screening For Heat-tolerance Rice And SSR Marker Analysis

Abstract:Rice is sensitive to the threat of high temperature during the whole growth period. Especially at flowering and grain filling stage, high temperature will result in the decreasing of the rice seed setting rate and grain quality respectively. Providing global warming in recent years, abnormal high temperature weather appeared more frequently. It’s urgent to screen for new rice germplasm with heat tolerance since most elite rice cultivars in practice are not resistant to heat stress. In this study, a multiple sowing experiment was conducted to screen for heat tolerance rice including the seed setting rate, grain quality, and their correlation with temperature at corresponding stage. Moreover, similarity coefficients calculation and cluster analysis among different rice lines were performed using72pairs of SSR primers. Results are as following:1. Natural high temperature reduced the seed setting rate mainly at flowering stage, and the reductions are variant among different materials tested. The seed setting rate is extremely significant correlated with the daily mean highest temperature at the heading stage, and significant correlated with the daily mean highest temperature3days before flowering.2. Natural high temperature affected the grain quality mainly in grain filling stage, and the influence is variant among different materials tested. The head rice rate is extremely significant correlated with the daily mean highest temperature11-15days after flowering, and the chalky area is significant correlated with the daily mean highest temperature6-20days after flowering.3. Both D43and D81were identified as heat tolerance local rice varieties in flowering period. In addition, Xiangwanxian17and Pin36are found to be stable in grain quality at filling stage under different temperatures.4. The SSR analysis results showed that genetic differences existed between the heat-resistant material and heat-sensitive material.