Study on the characteristics of reproductive biology of alfalfa

Chinese. 对兰州地区10个紫花苜蓿（Medicago sativa L.）品种的开花物候期、花部特征、花粉-胚珠比、花粉活力和种子产量性状等生殖生物学特性进行研究,结果表明：各品种花期时间持续了近一个月,花粉-胚珠比为3171.79～5759.64,该物种的繁育系统属于专性异交类型;各品种的花粉活力差异较大,变化范围为50.56%～80.76%;各品种的花冠长度、花托直径、每花序小花数、每单枝花序数、总小花数等花部特征差异较大,而已弹花数百分比差异不显著;每花序结荚数、结荚率、种子数,以及每荚种子数、单位面积单枝数和单位面积种子产量等性状差异较大,而种子千粒重差异不显著;其中Defa、Derby、Sitel和Prime的花部特征、花粉-胚珠比和种子产量性状都优于其他品种。此研究为揭示紫花苜蓿有性生殖生物学特性和兰州地区紫花苜蓿种植提供了一定的理论依据.

English. Plant sexual reproductive biology is a synthesized and advanced subject which studies plant sexual reproductive proceeding and regulatorymechanism. 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.