‘참동진/영호진미’ 재조합집단을 이용한 수량 관련 형질 양적형질 유전자좌 분석

QTL Analysis for Yield-Related Traits Using the Recombinant Inbred Lines Derived From a Cross Between ‘Chamdongjin’ and ‘Younghojinmi’

‘Chamdongjin’ is a near-isogenic line with enhanced disease resistance compared to ‘Sindongjin,’ a mega-cultivar in Korea. ‘Younghojinmi’ is the rice cultivar with the highest taste quality among the premium cultivars. This study conducted quantitative trait loci (QTL) analysis on yield-related traits using the recombinant inbred lines derived from a cross between ‘Chamdongjin’ and ‘Younghojinmi’ to elucidate genetic interaction. We utilized KASP markers and a target-capture sequencing SNP genotyping platform to address the insufficient genetic diversity of the population using Korean japonica cultivars. A QTL associated with heading date (HD), qHd8, was detected, and the candidate gene Hd18 was identified. The hd18 allele delayed HD by 3 days and reduced the brown/rough rice ratio (BRR) by 0.3%. QTLs associated with culm length (CL), panicle length (PL), and yield (g/plant), namely qCL1, qPL1_2023, and qYield1_2023, respectively, were detected, and the candidate gene SD1 was identified. The sd1 allele shortened CL and PL by 11 and 0.8 cm, respectively, and reduced the yield by 2.3 g. It also reduced the number of spikelets per panicle (NS) by 10 and decreased the ratio of ripened grains (RRG) by 2.6 %. QTLs associated with 1,000-grain weight (TGW), NS, and BRR, namely qTGW3, qNS3, and qBRR3_ 2023, respectively, were detected, and the candidate gene GS3 was identified. The gs3 allele increased TGW and BRR by 3.8 g and 0.4%, respectively, and reduced NS by 12. It also reduced RRG content by 1.9% and increased the yield by 1.7 g. The QTL associated with the number of panicles per hill (PN), qTN3, and the candidate gene, OsTB1, were identified. The OsTB1TGTG allele reduced PN by 1.3 and affected the increase in NS and RRG by 10 and 1.4%, respectively. The allele combinations of SD1, GS3, and OsTB1 were analyzed to assess their effects on yield-related traits. NS and RRG were influenced by trait variations, depending on the combination background of other alleles during allele substitution. ‘Jeonju 697,’ an elite breeding line exhibiting improved lodging resistance with shortened CL, was selected by substituting SD1 with sd1 while maintaining the Hd18-gs3-OsTB1TGTG allele combination of ‘Chamdongjin.’ This is expected to be a practical alternative for addressing the lodging problem in ‘Chamdongjin.’