Abstract: Medicago falcata Ximeng (female) and M.sativa Tashenkuergan (male) were crossed.The hybrid F1 self-crossed to produce 89 individuals of F₂ segregating population.The morphological characters,agronomic characters and nutrient contents of the tetraploid alfalfa family were analyzed to understand genetic variability and the rule of inheritance.Results indicated that flower colors were separated in the F₂ population.There were 20 plants with purple flowers (22.47%),33 plants with yellow flowers (37.08%)and 36 plants with variagated flowers (40.45%).Plant types were also separated in F₂ population.There were 32 plants with erect types (35.96%),45 plants with half-erect types (50.56%),and 12 plants with creeping types (13.48%).Fresh weight,dry weight and branch number were the main variation traits.Their coefficients of variation all are more than 80%.Internodes number had the smallest coefficients of variation (19%) among all agronomic traits.The morphological characters,agronomic characters and nutrient content in F₂ population possess widely differences.This research provided a foundation for subsequent map construction and QTL location.

Key words: Tetraploid, Alfalfa family, Morphology, Agronomy, Nutrient content, Genetic variation analysis

摘要： 以内蒙古锡盟黄花苜蓿(Medicago falcate Ximeng)为母本、塔什库尔干紫花苜蓿(M.sativa Tashenkuergan)为父本杂交,F1杂交种自交得到89株F₂分离群体,对此四倍体家系的形态性状、农艺性状及营养成分含量进行分析,以期了解该家系内各性状遗传变异并探讨其遗传规律。结果表明:其中F₂代杂花36株,黄花33株,紫花20株,所占比例分别是40.45%,37.08%和22.47%,株型分为直立型32株(35.96%),匍匐型12株(13.48%),半直立型45株(50.56%);农艺性状变异排前3位的为鲜重>干重>分枝数,变异系数均达到了80%以上;变异系数最小的是节间数,只有19%;营养成分含量变异排前3位的为脂肪>Ca元素>P元素。F₂群体的形态性状、农艺性状及营养成分含量各性状都存在不同差异,是数量性状的遗传特点,可为后续的图谱构建和QTL定位提供一定的基础。

关键词: 四倍体, 苜蓿家系, 形态性状, 农艺性状, 营养成分含量, 遗传变异分析