Mapping of QTLs for Yield Traits Using an Advanced Backcross Population from a Cross between Oryza sativa and O. glaberrima

An interspecific BC₃F₂ population (Milyang 23/O. glaberrima//3*Milyang 23) consisting of 141 lines was evaluated for 8 traits associated with yield. Oryza glaberrima (IRGC #103544) was phenotypically inferior to all of the traits examined in this study. However, several transgressive segregants outperformed Milyang 23 with respect to 1,000-grain weight, spikelets per panicle and grain yield. A genetic linkage map generated for this population consisted of 124 SSR markers with an average interval length of 13.1 cM. The percentage of O. glaberrima genome, which was calculated on the number of the exotic gene introgressions contained in the 141 BC₃F₂ lines, ranged from 3.9 to 25.4% with a mean of 12.8%. Of the 37 QTLs associated with yield and yield components, 24 alleles from O. glaberrima were favorable. However, eight QTLs were significantly associated with yield and five alleles of O. glaberrima were located on chromosomes 2, 3, 4, 6 and 8 which is attributed to increasing yield ranging from 1.5 to 2.2 tons/ha. Exploitation of the genetic potential of exotic species using molecular markers might provide a new opportunity to improve yield and quantitative traits in rice breeding program.