Identification of Yield and Yield-Related Quantitative Trait Loci for the Field High Temperature Condition in Backcross Populations of Rice (Oryza sativa L.)

The yield related traits are controlled by multiple quantitative trait loci (QTLs) and influenced by environmental change in rice. We analyzed QTLs for 15 yield related traits using two backcross populations, derived from crosses between IR64 as recurrent parent and Koshihikari as donor parent, through two years. A total of 67 backcross inbred lines (BILs) and 40 chromosome segment substitution lines (CSSLs) were genotyped using 183 SNP markers using a high-throughput genotyping system. Some genomic gaps between markers were identified in two populations. For fifteen traits in this study, 36 major QTLs (mQTLs) for 12 traits and 16 digenic epistatic QTLs (EpQTLs) for culm length were detected in BILs. On the other hand, 17 mQTLs were detected for nine traits in CSSLs. Among them, six mQTLs for grain yield traits were collocated on chromosome 10 in both years. For spikelet fertility, six putative QTLs were detected under high temperature conditions in 2018. The QTLs identified in this study could be used for the development of rice varieties conferring inter-subspecific combinations of yield-related traits.