title: Gene actions of QTLs affecting several agronomic traits resolved in a recombinant inbred rice population and two backcross populations.
abstract: To understand the types of gene action controlling seven quantitative traits in rice, we carried out quantitative trait locus (QTL) mapping in order to distinguish between the main-effect QTLs (M-QTLs) and digenic epistatic QTLs (E-QTLs) responsible for the trait performance of 254 recombinant inbred lines (RILs) from rice varieties Lemont/Teqing and two backcross hybrid (BCF1) populations derived from these RILs. We identified 44 M-QTL and 95 E-QTL pairs in the RI and BCF1 populations as having significant effects on the mean values and mid-parental heterosis of heading date, plant height, flag leaf length, flag leaf width, panicle length, spikelet number and spikelet fertility. The E-QTLs detected collectively explained a larger portion of the total phenotypic variation than the M-QTLs in both the RI and BCF1 populations. In both BCF1 populations, over-dominant (or under-dominant) loci were more important than additive and complete or partially dominant loci for M-QTLs and E-QTL pairs, thereby supporting prior findings that overdominance resulting from epistatic loci are the primary genetic basis of inbreeding depression and heterosis in rice.
authors.affiliation: Shanghai Agrobiological Gene Center, 2901 Beidi Road, Shanghai, 201106, China.
authors.forename: H W
authors.initials: HW
authors.lastname: Mei
authors.forename: Z K
authors.initials: ZK
authors.lastname: Li
authors.forename: Q Y
authors.initials: QY
authors.lastname: Shu
authors.forename: L B
authors.initials: LB
authors.lastname: Guo
authors.forename: Y P
authors.initials: YP
authors.lastname: Wang
authors.forename: X Q
authors.initials: XQ
authors.lastname: Yu
authors.forename: C S
authors.initials: CS
authors.lastname: Ying
authors.forename: L J
authors.initials: LJ
authors.lastname: Luo
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D003433:Crosses, Genetic; D004843:Epistasis, Genetic; D017343:Genes, Plant; D006824:Hybridization, Genetic; D012275:Oryza / Q000235:genetics; D040641:Quantitative Trait Loci; D011995:Recombination, Genetic