Locating QTL Controlling the Yield-Related Traits in Perennial Chinese Rice “Shendao3#”

Shendao3# (SD3#) exhibits perennial characteristics. Identifying the QTLs underlying the yield-related traits in SD3# provides a theoretical basis for future perennial rice breeding. In this study, SD3# and an F2 population derived from a cross between SD3# and XieqingzaoB (XQZB) and its bi-parents were selected as experimental materials. A total of fifteen yield-related traits including plant height, effective panicle per plant and thousand-grain weight in the SD3#-population and its bi-parents were investigated for both phenotypic analysis and QTL mapping. Results indicated that the fifteen yield-related traits in the SD3#-population exhibited quantitative genetic characteristics suitable for QTL analysis. Altogether, 25 QTLs underlying the yield-related traits and 26 pairs of epistatic QTLs were identified; these explained phenotypic variances ranging from 4.21% to 27.30% and 1.24% to 19.30%. Of these, nine novel QTLs underlying unfilled grain per panicle (UGP), spikelet per panicle (SP), seed setting density (SSD), grain yield per plant (GYP) and thousand-grain weight (TGW) with additive effects derived from SD3# were detected on the first, second, fourth, eighth, ninth, and tenth chromosomes. Six pleiotropic QTLs underlying two or more traits were detected on the first, fourth, seventh, eighth, and eleventh chromosomes. This work lays a good foundation for both the yield-related gene mined from SD3# and future perennial Chinese rice breeding.