数量性状水平上甘、青两省春小麦品种间的遗传多样性现状及演变趋势

Detection on evolvement and present situation of genetic diversity of spring wheat cultivars planted in Gansu and Qinghai Provinces using quantitative characters

在数量性状水平上 ,调查了 43个春小麦品种的 1 9个数量性状 ,利用主成分分析法计算品种间的欧氏平方遗传距离 ,并在此基础上用最小方差法做了聚类分析。发现 43个品种间在数量性状水平上的遗传距离变异范围很大 ( 0 .92 6～ 67.942 ) ,平均遗传距离为 1 8.0 0 0 ,说明供试品种的 1 9个考察性状上存在较大的表型变异。从聚类结果来看 ,地方品种基本上被聚在一起 ,说明地方品种同引进品种和育成品种至少在表型上存在较大差异。从 2 0世纪 40年代以来 ,在数量水平上甘、青两省春小麦地方品种间的遗传多样性水平最高 ( GD=31 .389) ,其次是 2 0世纪 5 0年代引进品种 ( GD=2 6.30 8) ,而育成品种间的遗传多样性水平最低 ,总体上呈下降趋势。说明随着育种进程的深入 ,作为育种目标追求的经济性状趋于一致 ,其变异集中在一个狭小的范围之内 。

Squared Eudlidean genetic distance (GD) between 43 accessions was calculated using principal component analysis based on 19 investigated quantitative characters.Clustering analysis was conducted on the basis of GD matrix using Wards method.The results show that range of genetic distance among 43 accessions is 0.926-67.942,mean genetic distance is 18.000,so there exists extensive phenotypic variation based on the 19 quantitative characters.Clustering results show that landances were clustered into the one group.The results indicate that there exists more variation between landraces and introduced cultivars (or bred cultivars) at least in phenotype level.On quantitative characters,genetic diversity among introduced cultivars in 1950s (GD=26.308) is higher than that of bred cultivars which have the trend to decrease,but less than that of landraces (GD=31.389).The all results show that with development of breeding,genetic diversity will be down because economic characters become alike and their variation among bred cultivars will gather in narrow range.