Mapping and introgression of QTL for yield and related traits in two backcross populations derived from Oryza sativa cv. Swarna and two accessions of O. nivara

Advanced backcross QTL (AB-QTL) analysis was carried out in two Oryza nivara -derived BC 2 F 2 populations. For nine traits, we identified 28 QTL in population 1, and 26 QTL in population 2. The two most significant yield-enhancing QTL, yldp9.1 and yldp2.1 , showed an additive effect of 16 and 7 g per plant in population 1, while yld2.1 and yld11.1 showed an additive effect of 11 and 10 g per plant in population 2. At least one O. nivara -derived QTL with a phenotypic variance of more than 15% was detected for seven traits in population 1 and three traits in population 2. The O. nivara -derived QTL ph1.1 , nt12.1 , nsp1.1 , nfg1.1 , bm11.1, yld2.1 , and yld11.1 were conserved at the same chromosomal locations in both populations. Two major QTL clusters were detected at the marker intervals RM488–RM431 and RM6–RM535 on chromosomes 1 and 2, respectively. The co-location of O. nivara -derived yield QTL with yield meta-QTL on chromosomes 1, 2, and 9 indicates their accuracy and consistency. The major-effect QTL reported in this study are useful for marker-assisted breeding and are also suitable for further fine mapping and candidate gene identification.