水稻籼粳交DH群体花器性状的遗传分析

Genetic Analysis of Floral Characters in A DH Population Derived from An indica/japonica Cross of Rice

水稻花器性状是影响杂交稻制种异交结实率的重要因素之一。利用一个水稻籼粳交(窄叶青8号/京系17)来源的DH群体对水稻柱头外露率、花柱长、柱头长、柱头宽、花药长、花药宽、颖花长、颖花宽和颖花长宽比9个花器性状和穗抽出度进行遗传分析。不论性状在2个亲本间的差异显著与否,在DH群体中10个研究性状在基因型间的差异均达到极显著水平(P<0.01),并表现为连续变异和明显的超亲分离。除花药宽的遗传力较低(50%)、且估计的基因数多达13个之外,其余9个研究性状的遗传力均较高,为68%～93%,控制这些性状的基因数估计为7～10个。这些结果表明,10个研究性状均为受多基因控制的数量性状,其增效和减效基因在2个亲本中均有分布,通过基因重组可产生正向和负向两个方向的超亲基因型。除了柱头长、柱头宽和穗伸出度3个性状未发现有基因间的上位性互作外,其余7个性状均检测到显著的互补性互作。性状相关和通径分析的结果显示,与柱头外露率关系最密切的花器性状为柱头长、柱头宽和颖花长宽比,颖花长和颖花宽主要通过影响颖花长宽比来对柱头外露率产生影响。其次,与柱头外露率关系较密切的为花柱长。柱头外露率高的基因型通常表现为长柱头、长粒型和长花柱。花药长、花药宽与上述花器性状间的相关性较弱。在DH群体中。

The behavior of floral characters is one of the important factors influencing outcrossing and hybrid yield in seed production of rice hybrid.By using a DH population derived from a rice indica/japonica cross,genetic analyses of floral characters,such as percentage of exserted stigmas,stigma length,stigma width,style length,anther length,anther width,spikelet length,spikelet width,length-width ratio of spikelet,and panicle exsertion degree,were conducted in the present study.There were highly significant differences (P<0.01) among genotypes in the DH population for all of the studied traits regardless of marked difference or no difference between the two parents for the traits.All of the traits showed continuous variation and large aggressive segregation.Anther width had a relatively lower heritability of 50% and the number of genes involved in the trait was estimated to be up to 13,while for other 9 traits the heritabilities and gene numbers were estimated to be 68%-93% and 7-10,respectively.These results suggested that all of these traits were quantitatively inherited and that the two parents had their different positive alleles for the traits which could be recombined to produce more superior genotypes.Except stigma length,stigma width and panicle exsertion degree,significant complementary gene interactions for other 7 traits were detected.Phenotypic correlation and path analysis revealed that the floral traits such as stigma length,stigma width,and length-width ratio of spikelet were most highly associated with stigma exsertion percentage.The genotypes with high stigma exsertion percentage appeared to have long stigmas,long grains and long styles.Anther length and width were less associated with stigma exsertion percentage.For panicle exsertion degree large variations were observed in the DH population,but no gene interaction was detected,implying the additive effects as the genetic main effects for the trait.