Abstract: Results of path-coefficient analysis on the correlative traits of different aged alfalfa plants indi cated that number of shoots per plant had indirect positive effect on seed weight per plant, they were positive ly correlated on one-year-old alfalfa plant.But on three-year-old alfalfa plant, number of stems per plant had indirect negative effect on seed weight per plant and they were negative correlated.The reason was that num ber of shoots Per plant multiplied with age and the enviromental and nutrient conditions were worsened.Number of maturated racemes, dry weight per plant, 1000 seed weight and stem diameter showed positive correlation with seed weight per plant in different-aged plants, among them, stem diameter had indirect posi tive effect on seed weight per plant.The growth of alfalfa crown would stimulate the increment of stoots.These change of alfalfa crown had bad effect on seed yeild.

Key words: Alfalfa, Seed production, Seed yeild of single alfalfa plant, Path-coefficient analysis

摘要： 不同生长年限留种苜蓿的单株粒重与相关性状的通径分析结果表明:当年生单株枝条数对单株粒重的作用表现为间接的正效应,二者呈正相关(r＝0.59),而三年生的单株枝条数对单株粒重则表现为间接的负效应,二者呈负相关(r＝-0.63),其原因是单株枝条数的逐年增加恶化了生殖生长的环境和营养条件。有效花序数、单株干重、千粒重、茎粗等性状在不同生长年份均与单株粒重呈正相关。茎粗对单株粒重的作用主要表现为间接正效应。苜蓿根颈逐年增大导致单株枝条数的增多,对种子产量的提高有不利的影响。

关键词: 苜蓿, 种子生产, 单株产量, 通径分析