四倍体杂交冰草F_(2)群体农艺性状聚类、相关及通径分析

Correlation,cluster,and path analysis of agronomic traits of the F_(2)population from tetraploid hybrid crested wheatgrass

为深入开展四倍体冰草数量性状产量基因定位分析、优良新种质选育研究,以四倍体杂交冰草F_(2)群体的120个分离单株及其亲本蒙古冰草(Agropyron mongolicum)、航道冰草(Agropyron cristatum‘Fariway’)为材料,对其株高、叶长、叶宽、穗长、穗宽、茎粗、茎叶比和单株鲜重8个产量相关的农艺性状进行了测定分析。结果表明,该群体各性状均为受多基因控制的数量性状,呈正态分布,且存在超亲分离现象。聚类分析显示,在欧氏距离为17.5处,将F_(2)群体分为3个类群,其中第1、3类分别表现出优质和高产的特性。相关及通径分析表明,对单株产量影响最大的性状是株高(r=0.265,P<0.01),直接通径系数为0.174,其后依次为穗长(r=0.214,P<0.05)、茎叶比(r=0.197,P>0.05)和茎粗(r=0.109,P>0.05)。本试验结果可为高产优质的四倍体杂交冰草新品种培育奠定基础。

To lay a foundation for further gene mapping analysis of quantitative traits related to yield and the breeding of excellent new germplasm for tetraploid wheatgrass,120 individual plants from the F_(2)population of tetraploid crested wheatgrass and their parents(Agropyron mongolicum×A.cristatum‘Fariway’)were used as materials.Eight agronomic traits,including plant height,leaf length,leaf width,panicle length,panicle width,stem diameter,stem-leaf ratio,and fresh weight per plant were analyzed.The results showed that all of these traits were quantitative traits controlled by multiple genes,with a normal distribution and transgressive segregation.Cluster analysis showed that the F_(2)population was divided into three groups at a Euclidean distance of 17.5.The first and third groups showed superior quality and high yield,respectively.Correlation analysis and path analysis showed that plant height had a significant effect on fresh weigh per plant,with a correlation coefficient of 0.265(P<0.01)and a direct path coefficient of 0.174.This was followed by spike length(r=0.214,P<0.05),stem-leaf ratio(r=0.197,P>0.05),and stem diameter(r=0.109,P>0.05).The results provided the basis for breeding new varieties of tetraploid hybrid crested wheatgrass with high quality and high yield.