与水稻籼粳分化有关的穗颈维管束性状基因的分子标记定位

水稻穗颈维管束数及其与穗一次枝梗数之比（V／R）是与籼粳分化有关的重要性状，采用籼粳交（圭630／02428）杂种F1花药培养获得的DH群体，对水稻穗颈维管束数，穗一次枝梗数及V／R比进行了QTL分析，检测到3个控制穗颈维管束数的QTL；其中，效应最大的qVB-8的贡献率为31．1％，加性效应值为1．96％，增效等位基因来自灿稻亲本圭630，2个控制一次枝梗数的QTL效应较小，但分别与控制穗颈维管束数的2个QTL同位，检测到影响V／R比的3个QTL，其中，效应最大的qV/R-1的贡献率为25．3％，被定位于第1染色体上，与落粒性基因sh-2紧密连锁（亦或为一因多效）。此外，还检测到4对和2对分别控制穗颈维管束数和V／R比的互作QTL。结果分析表明，水稻穗颈维管束数与穗一次枝梗数受不同的多基因系统控制，但这2个多基因系统的某些位点在基因组中具有同位性；在第1染色体上，控制V／R比，且效应最大的qV/R-1所在的染色体区段在水稻籼粳分化过程中可能具有重要作用。

Molecular Mapping of Quantitative Trait Loci (QTL) for Characters of Vascular Bundles in Peduncle Related to indica-japonica Differentiation in Rice (Oryza sativa L.)

A doubled haploid population, consisting of 81 DH lines derived from the F 1 hybrid of a cross between an indica cultivar and a japonica cultivar, was used to map quantitative trait loci (QTL) controlling numbers of vascular bundles in peduncle, primary rachis branches and the ratio of vascular bundles to primary rachis branches (V/R ratio). For vascular bundles, three QTL were detected. Among them, the QTL qVB 8 with the largest effect individually accounted for 31.1% of the total variation. Two QTL controlling primary rachis branches were identified and they were co located with 2 of the 3 QTL for vascular bundles respectively. Three QTL for the V/R ratio were mapped on chromosome 1,2 and 8, respectively. Of the three QTL, the QTL qV/R 1 with the largest additive effect, explained 25.3% of the total variation, was located on chromosome 1 and found to be closely linked to the gene sh 2 , a major gene underlying grain shattering ability. In addition, four and two pairs of significant epistatic QTL were detected for vascular bundles and the V/R ratio, respectively, but none for rachis branches. Our results suggested that the numbers of vascular bundles and primary rachis branches were independently controlled by different polygenic systems, but the two polygenic systems shared a fraction of quantitative trait loci. It was also shown that the chromosome region carrying the QTL qV/R 1 on chromosome 1 might play an important role in the processes of indica japonica differentiation in rice.