节节麦大穗大粒相关农艺性状的遗传分析

Genetic Analysis for Long-Head and Big-Kernel Related Traits fromAegilops tauschii

节节麦(Aegilops tauschii,DD)是六倍体普通小麦D基因组的祖先,其自然类群中含有丰富的抗逆、高产基因,利用其与四倍体硬粒小麦合成的六倍体小麦在现代小麦育种中得到了愈来愈多的应用。本课题在野生节节麦类群中发现了大穗、大粒材料AT462,利用其作母本与节节麦材料AT18(强分蘖)杂交;构建了F2、F3群体,通过调查亲本和群体单株的穗长、小穗数、粒长、粒宽和粒重等表型,对这些穗部性状进行了相关性分析和遗传分析。结果表明:(1)在F2和F3群体中,粒重、粒长与穗长之间不存在显著相关性,而且穗长与粒宽之间在两个群体中的平均相关系数绝对值小于0.1,粒重与小穗数之间的相关系数绝对值小于0.2,表明节节麦大粒相关性状不受穗长的影响,受小穗数影响也较小;(2)采用F2单世代分离分析的方法对节节麦AT462×AT18的F2群体大穗、大粒相关性状进行遗传分析,其中穗长受2对具有加性效应的主效基因控制;粒重和小穗数均同时受2对基因的加性效应、显性效应以及互作效应控制,其中加性效应占主导地位;粒长、粒宽均受2对基因的加性效应、显性效应以及互作效应控制,且三种效应较为均衡。这说明控制节节麦粒重、穗长、小穗数等产量性状相关基因的加性效应在遗传中占主导地位,在育种中较易利用,且其主效基因的遗传力达0.9。

Aegilops tauschii, the diploid D genome progenitor of the hexaploid wheat, has been used to improve modern common wheat through creating synthetic hexaploid wheat by crossing with durum wheat, as a bridging mechanism for wheat breeding and gene pool for environmental stress resistance and high yield. In this study, we obtained an accession AT462 with long-head and big-kernel in the wild tauschii gene pool and created the populations of F2 and F3 by crossing with the other Aegilops tauschii accession AT18. A total of 5 yield-related traits were investigated, including spike length, spikelets per spike, kernel length, width and weight. The results of correlation and genetic analysisare as follows. （1） In the F2 and F3 populations, there was no significant relationship between kernel- related traits including grain weight, kernel length and spike length. The absolute value of average correlation coefficient between spike length and kernel width was less than 0.1, and the absolute value between kernel weight and spikelet number per spike was less than 0.2. These results indicated that the expression of the big kernel related traits was not significantly influenced by spike length and less affected by spikelets per spike. （2） Kernel length was controlled by two pair of major genes with addi- tive effects only with F2-generation separation genetic analysis. Both kernel weight and spikelets per spike were controlled by two major genes, and their additive effects were the strongest among the three kinds of genetic effects. The segregations of kernel length and kernel width were controlled by both additive, dominance and interaction effects of genes in F2 population, where three types of genet- ic effects were distributed in a relatively equitable manner. These results suggested that the long-head and big-kernel related traits such kernel weight, spike length and spikelets per spike were mostly de- termined by the additive effects of genes with their heritability more than 0.9, which was easily uti- lized in breeding.