[O41] Genetic Improvement of Crop Yield

[O41-05] Identification of QTLs for Strong Culm with Pleiotropic Effect on Panicle Morphology by GWAS Using Rice Varieties in Japan

*Nominated for Presentation Awards

^○Tomohiro Nomura¹, Kenji Yano², Makoto Matsuoka³, Ko Hirano³, Shunsuke Adachi⁴, Francisco Javier Piñera-Chavez⁵, Matthew Paul Reynolds⁵, Taiichiro Ookawa¹ (1.Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Japan, 2.Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project, Japan, 3.Bioscience and Biotechnology Center, Nagoya University, Japan, 4.College of Agriculture, Ibaraki University, Japan, 5.Global Wheat Program, International Maize and Wheat Improvement Center, Mexico)

Since the "Green Revolution", semidwarf1 (sd1) has been used for breeding rice (Oryza sativa L.) with shorter culms to prevent lodging, thereby contributing to food sufficiency especially in Asia. However, it has been pointed out that semi-dwarf varieties have low yield potential because of their low biomass production (Okuno et al., PLoS ONE, 2014). In addition, in recent years, typhoons have become larger due to global warming, and the rice lodging due to 'Super typhoons' has become serious problem in Japan and Southeast Asia. Therefore, in the future, it is important to enhance lodging resistance by strengthening rice culms while still achieving high yield. In this study, novel quantitative trait loci (QTLs) for traits associated with a strong culm were identified using genome-wide association study (GWAS), and pleiotropic effects of the QTLs on panicle morphology associated with yield components were evaluated. In 2018 and 2019, 168 and 334 japonica varieties including native varieties in Japan except Hokkaido were evaluated, respectively. High peaks associated not only the outer minor axis but also the number of secondary branches were detected on chromosome 1S, 2S, 2L and 8L in 2018, and chromosome 2L, 3S, 4L, 8L, 9L and 11S in 2019. Near the peak on chromosome 8L, OsSPY related to the plant architecture is located (Yano et al., PNAS, 2019), suggesting that OsSPY may affect not only panicle architecture but also culm thickness.