醇溶蛋白水平上甘、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 by gliadin markers

用APAGE技术检测了43个春小麦品种在醇溶蛋白水平上的遗传变异,在计算Jaccard相似系数的基础上用UPGMA方法进行聚类分析.共得到42种不同的带型,电泳共分离出37条带,其中33条具有多态性.品种间在醇溶蛋白水平上的遗传距离变异范围很大 0.0000～0.8148 ,平均遗传距离GD=0.5073.说明43个品种在醇溶蛋白编码位点上存在较大变异.聚类结果显示,除佛手麦自成一类外 GS=0.28 ,地方品种和引进品种与大多数育成品种 GS=0.46 分属不同的亚类,说明育成品种同地方品种和引进品种在醇溶蛋白编码基因上存在较大变异.育成品种间在醇溶蛋白水平上的遗传多样性程度不高,这一结果提示在这一地区进行与醇溶蛋白相关的品质育种很难在现有的育成品种间杂交的基础上取得成功.从遗传多样性的演变趋势来看,历史上以地方品种间醇溶蛋白的遗传变异程度最大 GD=0.5455 ,50年代引进品种变异程度最小 GD=0.3310 .从60～90年代,育成品种醇溶蛋白水平上的遗传多样性有一先增后减的过程,但总体上变异程度要低于地方品种,其原因与亲本单一和育种目标由高产到优质变化条件下人工选择压由弱到强有关.

The genetic variation among 43 accessions was detected by APAGE technique upon gliadin. 42 electrophoresis patterns were obtained. 37 bands were separated. Among them 33 bands are polymorphic. Jacaard genetic similarity (GS) shows that there is large genetic variation in gliadin among 43 accessions. Range of genetic distance (GD) among 43 accessions in gliadin is 0.0000~0.8148, mean genetic distance is 0.5073. So there exists extensive genetic variation at coding loci of gliadin among 43 accessions. Clustering results analyzed by UPGMA based on GS matrix show that except Foshoumai, landraces and introduced culativars belong to the one group, but majority of bred cultivars belongs to the other group at the level of GS 0.46. So it could be concluded that there exists abundant genetic variation between bred cultivars and landraces (or introduced cultivars) at coding loci of gliadin. Above all, it is difficult to breed spring wheat cultivars related with gliadin successfully, which is based on the cross among existing bred cultivars in this region. As far as development of genetic diversity in gliadin, there exists the most extensive variation among landraces (GD=0.545 5) and the least variation among introduced cultivars planted in 1950s (GD=0.331 0). Genetic diversity among bred cultivars in gliadin, which has the trend from increase to decrease, is less than that among landrances in general. The reason is relation to poor germplasm and change of artificial selection, which keep pace with change of breeding targets. Artificial selection acted on the cultivars was changed from weak to strong when breeding targets were changed from high yield to high quality.