Correlation analysis and QTL identification for canopy temperature, leaf water potential and spikelet fertility in rice under contrasting moisture regimes

Canopy temperature (CT), leaf water potential(LWP) and spikelet fertility (SF) of a set of RILs (F9) from the cross between Zhenshan97B and IRAT109 were investigated under two soil moisture regimes in a drought screen facility. In water stress condition, CT was negatively correlated with SF (r = -0.2867) and LWP (r = -0.2740), and LWP was positively associated with SF (r = 0.1696). These results indicated that the plant with high drought tolerant ability could maintain higher LWP and lower CT, leading to highe rSF. A total of 44 main effect QTLs were associated with CT,LWP and SF. The accumulated contributions of QTLs for CT,LWP and SF were 87.85%, 15.06%, 79.46% under well water condition and 72.61%, 87.68%, 33.29% under stress condition, respectively. Totally 45 pairs of digenic interactions were detected. The accumulated contribution of digenic epistasis on CT, LWP and SF were 55.69%, 47.15%, 48.15% under well water condition and 53.44%, 57.94%, 54.62% under water stress condition. Compared with other drought tolerance QTL mapping researches in rice, 19 main effect QTLs were found to be located at the same or closely conjoint regions.