关键词: 紫花苜蓿, 花部特征, 花粉-胚珠比, 种子产量

Abstract: Plant sexual reproductive biology is a synthesized and advanced subject which studies plant sexual reproductive proceeding and regulatory mechanism.This paper studied the reproductive biology,such as floral phenology,floral feature,pollen-ovule ratio,pollen viability and seed yield characteristics,of ten alfalfa cultivars in Lanzhou area.The results show that the breeding system of alfalfa is obligate xenogamy and the flowering time of tested alfalfa cultivars lasted one month.The variance breadth of pollen-ovule ratio was from 3171.79 to 5759.64 and the variance breadth of pollen viability was from 50.56% to 80.76% in ten alfalfa cultivars.The variance of floral features,such as corolla length,receptacle diameter,number of florets per raceme,number of racemes per twig and florets of unit area,was large,but that of tripped flowers was not significant.The variance of seed yield characteristics,such as number of pods per raceme,pod ratio,number of seeds per pod,number of seeds per raceme and number of twigs in unit area,were large,but the variance of 1000-seed weight was not significant.The floral feature,pollen-ovule ratio,and seed yield characteristics of Defa,Derby,Sitel,and Prime were superior to other cultivars.These results enucleated the reproductive biology of alfalfa and provided the theoretical basis to alfalfa cultivation in Lanzhou area.

Key words: Alfalfa, Floral feature, Pollen-ovule ratio, Seed yield