基于生殖性状的玉米自交系遗传多样性与遗传距离分析

Analysis of Genetic Diversity and Genetic Distance of Maize Inbred Lines Based on Reproductive Traits

为提高玉米自交系种质资源的利用效率,充分了解自交系的遗传基础,探明自交系种质资源间的亲缘关系,本试验田间种植30个玉米骨干自交系,分别对其18个生殖性状进行遗传变异、主成分和聚类分析,研究自交系种质的遗传多样性与遗传距离。结果表明:雄穗分枝数、苞叶重、雄穗长、轴粗、秃尖长变异系数均大于10%,变异丰富度高,粒长、穗行数、最长苞叶长、穗长、穗粗变异系数均小于2%,稳定性相对较高;遗传多样性指数(H′)为0.68~2.09,平均值为1.51,百粒重遗传多样性指数最大,苞叶层数遗传多样性指数最小;变异系数越大遗传多样性指数越高。主成分分析得出,前7个主成分对变异的累积贡献率达77.39%;以主成分得分值为坐标的二维排序图可得出,自交系7922、驻136、ZM7211、H1613、驻85、21H86、浚92-8、Mo17遗传多样性丰富。不同自交系间欧式距离变化范围为0.002~0.161,平均欧式距离0.031;在欧式距离为0.03时可将30个自交系划分为5个类群,在欧式距离0.01处则可进一步将其分成13个亚类,亚类间平均遗传距离为23.10。综上可知,根据不同育种目标选择相应的杂优模式可以提高自交系种质资源的利用效率,从而加快玉米品种的培育进程。

In order to improve the utilization efficiency of maize inbred lines,know about their geneticbases,and explore their relationships,18 reproductive traits of 30 maize backbone inbred lines planted in fieldwere analyzed by genetic variation analysis,principal component analysis and cluster analysis to study the genetic diversity and genetic distances of the inbred lines.The results showed that the variation coefficients oftassel branch number,husk weight,tassel length,cob diameter and bald tip length were greater than 10%with higher variation richness.The variation coefficients of grain length,ear row number,the longest husklength,ear length and ear diameter were all less than 2%indicating relatively higher stability.The average genetic diversity index(H')was 1.51 with a range from 0.68 to 2.09.The genetic diversity index of 100-grainweight was the highest,while that of husk layer number was the lowest.The larger the coefficient of variationwas,the higher the genetic diversity index was.Principal component analysis results showed that the cumulative contribution rate of the first seven principal components was 77.39%;the two-dimensional sorting chartobtained based on principal component scores showed that the inbred lines 7922,Zhu136,ZM7211,H1613,Zhu85,21H86,Xun92-8 and Mo17 had rich genetic diversity.The Euclidean distance of these inbred linesranged from 0.002 to 0.161 with the average of 0.031;at the Euclidean distance of 0.03,the 30 inbred linescould be divided into 5 groups,and at the Euclidean distance of 0.01,they could be further divided into 13subgroups with the average genetic distance between subgroups as 23.10.In conclusion,selecting heterosismodels for different breeding objectives could improve the utilization efficiency of inbred lines,thus acceleratethe breeding process of maize varieties.