水稻第6染色体短臂产量性状QTL簇的分解

Dissection of QTLs for Yield Traits on the Short Arm of Rice Chromosome 6

【目的】将水稻第6染色体短臂上产量性状QTL分解到更小的区间中。【方法】从珍汕97B/密阳46重组自交系群体筛选到针对第6染色体短臂RM587-RM19784区间的剩余杂合体,衍生了一个由221个株系组成的F2:3群体,种植于海南和浙江两地,考察每株穗数、每穗实粒数、每穗总粒数、千粒重、结实率和单株产量,建立SSR标记连锁图,应用Windows QTL Cartographer2.5检测QTL。【结果】在所分析的6个性状中,除穗数外在第6染色体短臂上的目标区间均检测到QTL,分别座落于目标区域中3个以上的不同区间中,单个QTL对群体性状表型变异的贡献率为6.3%～35.2%;控制产量构成因子的QTL基本以加性作用为主,但3个单株产量QTL的显性度分别为1.65、0.84和0.42。【结论】目标区间存在3个以上的产量性状QTL,且同一区间控制不同性状的QTL、不同区间控制同一个性状的QTL在遗传作用模式、效应方向和效应大小上存在一定差异。

[Objective] The objective of this study was to dissect quantitative trait loci （QTL） controlling yield traits on the short arm of rice chromosome 6. [Method] A residual heterozygous line for interval RM587-RM19784 on the short arm of rice chromosome 6 was selected from Zhenshan 97B/Milyang 46 recombinant inbred population. An F2：3 population of 221 lines was derived and grown in two trial sites. Six yield traits including number of panicles per plant, number of filled grains per panicle, total number of spikelets per panicle, spikelet fertility, 1 000-grain weight and grain yield per plant were evaluated. A SSR marker linkage map was constructed and employed to detect QTL for yield traits using Windows QTL Cartographer 2.5. [Result] QTLs were detected for each of the traits except panicle number, with phenotypic variance explained by a single QTL range of 6.3%-35.2%. Most of the QTLs for yield components acted as additive QTL, while the three QTL for grain yield had dominance degrees of 1.65, 0.84 and -0.42, respectively. [Conclusion ] Three or more QTLs for yield traits were located in the target region. The genetic action mode, the direction of QTL effect and the magnitude of QTL effect sometimes varied among different QTLs for a given trait, and among QTLs for different traits that were located in a same interval.