白花草木樨第二次轮回选择半同胞家系农艺性状的遗传变异分析

Analysis of genetic variation in agronomic traits of half-sib families of Melilotus albus in the second generation of recurrent selection

为了选育出优质、高产、低香豆素的白花草木樨新品种,在前期完成第一次轮回选择的基础上,开展了25份白花草木樨半同胞家系的第二次轮回选择,在甘肃省榆中县和临泽县进行产量、品质、香豆素含量等农艺性状评价。方差分析结果表明半同胞家系间株高、干重、纤维、香豆素含量等性状具有显著的基因型变异(P<0.05),且干重、株高、茎粗等性状在两地点间存在显著的基因型与环境互作(P<0.05),根据基因型方差预测干重与株高的遗传增益增加百分比分别为4.3%和2.6%。相关性分析表明,茎粗与干重、株高有极显著(P<0.01)的正相关关系,粗蛋白与中性洗涤纤维、酸性洗涤纤维有极显著的负相关关系。主成分分析反映出各农艺性状间的关系和25份半同胞家系在各性状上的表现,聚类分析将25份家系分为4个组,其中第4组具有较高的干重、粗蛋白和最低的香豆素含量。通过对25份半同胞家系的第二次评价将为白花草木樨新品系选育奠定基础。

This research formed part of a program to breed a new cultivar of Melilotus albus with high quality,high yield and low coumarin content.In pursuit of this goal,we conducted a second recurrent selection at two sites,of 25 half-sib families of M.albus,on the basis of the first recurrent selection.Significant genotypic variation(P<0.05)between half-sib families were found for plant height,dry weight,fiber content and coumarin content,and there were significant genotype×environment interactions(P<0.05)between the two locations for most traits,including dry weight,plant height and stem diameter.The predicted genetic gain of dry weight and plant height traits were 4.3%and 2.6%,respectively,based on genotypic variance.The correlation analysis showed that the stem diameter was significantly positively correlated with dry weight and plant height(P<0.01),and the crude protein concentration was significantly negatively correlated with neutral detergent fiber and acid detergent fiber levels(P<0.01).Principal component analysis was used to show the relationship among agronomic traits and the performance of the half-sib families.The 25 half-sib families were divided into four groups by cluster analysis.Among these four groups,the third group had relatively high dry weight and crude protein,as well as lowest coumarin content.This second recurrent selection of 25 half-sib families will provide useful germplasm for breeding new lines of M.albus.