应用近等基因系初步定位粳稻孕穗期的耐冷基因

Mapping Cold Tolerance Gene by Near-Isogenic Lines at Booting Stage in japonica Rice

在昆明低温冷害条件下对十和田×(十和田5/昆明小白谷BC4F5)的BC5F2群体进行了耐冷性状的遗传研究。结果显示,穗期耐冷性受贡献率较大的基因控制。用平均分布于12条染色体的164个SSR标记对十和田、昆明小白谷、近等基因系池(NILP)进行筛选,在第5染色体长臂末端有2个SSR标记的扩增产物在十和田与昆明小白谷、NILP间有多态性。用这2个多态性标记对群体进行分子标记定位,单向方差分析表明RM31与耐冷基因连锁。再在RM31附近合成12个SSR标记在轮回亲本(RP)、近等基因系(NIL)间进行多态性筛选,只有RM7452有多态性,单向方差分析表明该标记与耐冷基因连锁。耐冷基因与RM7452、RM31的遗传距离分别为4.8cM和8.0cM,主穗结实率能解释表型变异的10.50%;实粒数能解释表型变异的5.10%。暂将这个耐冷基因定名为Ctb(t)。

Genetic analysis showed that cold tolerance at the booting stage in near-isogenic line(NIL) of Kunmingxiaobaigu was controlled by gene with large phenotypic variance. One hundred and sixty-four simple sequence repeat(SSR) markers on 12 chromosomes were used to detect polymorphism between Towata (RP) and near-isogenic line pool(NILP). Two SSR markers at terminal of long arm of chromosome 5 had polymorphism in comparison with RP genome. RM31 of them was found possibly linked with the cold tolerance gene at the booting stage through one-way ANOVA, then 12 SSR markers around RM31 were used for further detection of polymorphisms between RP and NIL, and RM7452 had polymorphism. The locus of cold tolerance gene at the booting stage was mapped on chromosome 5 between RM7452 and RM31 with a genetic distance of 4.8 cM and 8.0 cM, respectively, which explained 10.50% of phenotypic variance and 5.10% of phenotypic variance of full filled grains. This gene was tentatively designated as Ctb(t).