香椿种质生长及叶部表型性状的遗传变异分析

Genetic variation of growth and leaf phenotypic traits of Toona sinensis(A.Juss.)Roem.germplasms

以84个香椿(Toona sinensis(A.Juss.)Roem.)种质为材料,对其2个生长性状和18个叶部性状(包含6个质量性状和12个数量性状)进行测定。结果显示,香椿6个叶部质量性状变异类型丰富,呈现出多态化特点,单一性状的主要表型多为1~2个。苗高、地径及叶部表型等14个数量性状在种质间的差异均达到极显著水平,且除地径外,其他性状的遗传方差分量均大于环境方差分量,表明此类性状主要受遗传控制。参试的14个数量性状的平均表型变异系数为20.35%,平均遗传变异系数为16.36%;综合表型和遗传变异系数,叶柄长度较其他性状变异大,而叶片夹角稳定性最高,各数量性状(除地径外)遗传变异系数与表型变异系数之差小于7%。香椿种质各性状间Shannon-Weaver遗传多样性指数相差不大(1.892~2.069),遗传多样性水平高,具有良好的遗传改良基础。聚类分析可将84个香椿种质分为5类,类群Ⅰ表现为生长旺盛、小比叶重型;类群Ⅱ生长较快、叶片较大;类群Ⅲ种质数量最多,属生长缓慢、大比叶重型;类群Ⅳ特征为大叶片、多叶型;类群Ⅴ为小叶片、稀叶型。研究结果表明参试香椿种质变异丰富,遗传多样性水平高,能为良种选育、遗传改良等研究提供丰富的遗传材料。

Using 84 germplasms of Toona sinensis(A.Juss.)Roem.,two growth traits and 18 leaf traits(including six quality traits and 12 quantitative traits)were determined.Results showed that the six leaf quality traits of the T.sinensis germplasms were rich in variability and showed polymorphism,and the main phenotypes of single traits were 1-2.The differences among germplasms in regard to 14 quantitative traits,including height,diameter,and leaf traits,were highly significant at the 0.01 level,and the genetic variance component of the other traits was larger than the environmental variance component,except for diameter,indicating that such traits were mainly controlled genetically.The average phenotypic variation coefficient of the 14 quantitative traits was 20.35%and the average genetic variation coefficient was 16.36%.Based on phenotypic and genetic variation coefficients,petiole length showed the greatest variation among traits,whereas leaf angle was the most stable.The difference between the genetic and phenotypic variation coefficients of the traits(except ground diameter)was less than 7%.The Shannon-Weaver genetic diversity index of different traits was similar(1.892-2.069),indicating that the T.sinensis germplasms exhibited high genetic diversity and a good basis for genetic improvement.The T.sinensis germplasms were divided into five groups based on cluster analysis.GroupⅠwas characterized by strong growth and low specific leaf weight;groupⅡgrew relatively fast and the leaves were relatively large;groupⅢcontained the largest number of germplasms,which showed slow growth and large specific leaf weight;groupⅣwas characterized by large leaves and multi-leaf type;and,groupⅤwas characterized by small and sparse leaves.Thus,this study showed that the T.sinensis germplasm was rich in genetic variation and diversity and could provide abundant materials for genetic breeding and improvement.