Yield Trait Variation and QTL Mapping in a DH Population of Rice Under Phosphorus Deficiency

To study the differences of quantitative trait loci (QTLs) for rice (Oryza sativa L.) yield and its component traits under different phosphorus applications, a double haploid (DH) population consisting of 116 lines was evaluated for yield per plant (YP) and its components including 1000-grain weight (GW), seed-setting percentage (SP), panicle number per plant (PN), and grain number per panicle (GN) under phosphorus deficiency and normal conditions. This DH population was derived from a cross between phosphorus-deficiency tolerant japonica rice IRAT109 and phosphorus-deficiency sensitive japonica rice Yuefu. There were significant differences in SP, PN, and YP for the DH population between the 2 conditions, whereas there was no significant differences in GW and GN. This result indicted that SP, PN, and YP were more easily influenced by phosphorus deficiency than GW and GN. Using 94 restricted fragment length polymorphism (RFLP) and 71 simple sequence repeat (SSR) markers that covered 1,535 cM of the rice genome, a total of 17 QTLs were detected for plant yield and its components under phosphorus deficiency. Among them, 12 QTLs explained over 10% of the phenotypic variation. Three tightly linked QTL regions on chromosomes 3, 6, and 7 were identified, respectively. These QTLs with high general contribution and tightly linked QTL regions may be useful for marker-assisted selection in phosphorus-deficiency tolerant and high yielding breeding in rice.