Identification of Quantitative Trait Loci for Agronomic Traits in Two Rice Populations Derived from a Cross with a Wide Compatibility Line

Hybrid sterility is the major obstacle that can act as a barrier to genetic recombination and limits favorable gene transfer during inter-subspecific crosses in rice. However, hybrid sterility can be overcome by utilization of wide-compatible varieties (WCV). In the present study, two F2 populations generated from crosses between a wide-compatibility line (HWC-line) and two Korean varieties, Dasan and Hwacheong were evaluated for eight agronomic traits. A total of 157 molecular markers consisted of 116 STS, 40 SSR and 1 FNP were used to create genetic linkage maps spanning all 12 chromosomes. Twenty-one main-effect QTLs (M-QTLs) were identified in HWC-line/Dasan (HD) population. These loci are populated with two QTLs for culm length, one for spikelet per panicle, one for spikelet fertility, four for grain length, five for grain width, five for grain shape, and three for 100 grain-weight. In HWC-line/Hwacheong (HH) population, 17 QTLs were detected including two QTLs for culm length, one for panicle length, one for spikelet fertility, five for grain length, three for grain width, three for grain shape, and two for 100-grain weight. Of the total 34 QTLs found in the two F2 populations, 9 QTLs associated with culm length, grain length, grain width and grain shape were newly identified in this study. These QTLs will be useful for further understanding the genetic basis of agronomic traits and for developing markers for selection in rice breeding. In addition, HWC-line could be used as a bridge for inter-subspecies crosses overcoming hybrid sterility.