[O31] Temperature Stress

[O31-04] Genetic Dissection of Heat Stress Tolerance at Anthesis among Three Rice Cultivars, IR64, Koshihikari, and Takanari

(Invited Speaker)

^○Toshiyuki Takai (Biological Resources and Post-harrvest Division, Japan International Research Center for Agricultural Sciences, Japan)

Heat stress tolerance at anthesis is an important trait to achieve sustainable rice production under ongoing global warming. Many studies challenged to identify quantitative trait loci (QTLs) for heat stress tolerance at anthesis. Yet, the effects of the detected QTLs were small, and they have not been validated properly. Only qHTSF4.1 was successfully fine-mapped as a heat stress tolerant QTL. Therefore, more genetic resources and QTLs for heat stress tolerance at anthesis need to be identified. In Japan, Koshihikari is a leading cultivar with good eating quality and Takanari is a high-yielding cultivar. Although genetic mechanism of good eating quality and high yield in each cultivar was being elucidated, the information on heat stress tolerance was limited. Therefore, we compared the heat stress tolerance at anthesis in the two cultivars with that in IR64, which is a mega variety in tropics but is susceptible to heat stress at anthesis. We found that both cultivars had a certain heat stress tolerance; Takanari and Koshihikari exhibited approximately 55% and 37% spikelet fertility, respectively, under high temperature (38℃) treatment while IR64 had only 2% spikelet fertility. These results suggest that Takanari and Koshihikari are promising genetic germplasms for heat stress tolerance at anthesis. In this session, I will introduce the current progress of genetic analysis for heat stress tolerance at anthesis among the three cultivars, IR64, Koshihikari, and Takanari.