FIGURE 3.

Effect of heat stress on the kernel weight of superior and inferior spikelets of rice at anthesis. These rice plants were subjected to heat stress of 40°C for 5, 10, and 15 days after flowering, and determined at maturity. (A) The pictures of the superior and inferior grains in both genotypes under control and heat stress. (B) The mean data of kernel weight of superior and inferior grains in both genotypes under control and heat stress. SS and IS were indicated as superior spikelets and inferior spikelets, respectively. 0 day was indicated as control that rice plants without heats stress imposed. SP were controlled in each rice plants except for the treatments of FP and TP. SP, FP, and TP present each rice plant possessing six panicles, four panicles, and two panicles, respectively. Vertical bars denote standard deviations (n = 3). Different letters indicate significant differences between the superior spikelets and inferior spikelets in the same cultivar (P < 0.05).