Abstract:

【Objective】 The aim of the present study was to reveal the genetic variation of fertility and the relationship with seed set of three subspecies and one varieties of Medicago sativa, offering theoretical reference for selecting and breeding of superior species. 【Method】 In this paper, genetic variations of pollen vigor and ovule numbers in nine 9 varieties of Medicago sativa belong to M. sativa subsp. falcate, M. sativa subsp. sativa, M. sativa subsp. caerulea and M. sativa var. media were studied. From 2007 to 2008, the pollen vigor, number of ovules per flower and their relationships with seed set were investigated respectively. 【Result】 There existed significant difference (P＜0.05) in pollen vigor and ovules per flower among these Medicago sativa plants, and the highest pollen vigor and ovules per flower were observed in Hungary (M. sativa subsp. sativa) with 85.48% and 13, respectively. According to the correlation analysis, the seeds set under self-pollination showed a significant linear correlation with pollen vigor (P＜0.01), while seed set under artificial-pollination showed a significant linear correlation with ovules per flower (P＜0.05). The variations of seed set among-varieties were larger than those of within-variety under self-pollination and artificial pollination, but variations of seed set within-varieties were larger than those among-varieties under open pollination. The results indicated that the ways of pollination had significant effects on seed set in Medicago sativa plants, and the number of seeds per inflorescence was self pollination＜artificial pollination＜open pollination. 【Conclusion】 The high genetic polymorphisms of pollen vigor and ovules per flower in Medicago sativa were observed. There was a positive correlation between seed set and pollen vigor under self pollination as well as ovules per flower under artificial pollination.

Key words: Medicago sativa L., subspecies, variety, pollen vigor, ovule, seed set