Preliminary Study The Heterosis Of Medicago Varia Using Morphological Method And SSR, EST-SSR

Alfalfa (Medicago sativa L.) is a herbaceous perennial legume, it is one of the world's oldest cultivated forage and is also the one of the most important forage in China. Medicago sativa has character of high yield, and Medicago falcata is an important species for alfalfa breeding because it has high resistance to cold and drought. The Medicago varia which come from M.sativa crossing with M.falcata, inherit its parents character, so it has high yield and high resistance to cold and drought.we choice 24 alfalfa as parents and 32 hybrid combination including 55 F1 alfalfa for the experimental materials, and we study the morphological level and the DNA level of them, and analyse genetic distance ,correlation and hetersis of them using morphological traits and SSR, EST-SSR molecular markers.In 24 parents alfalfa, M. sativa grow better than in the field (no including M. falcata came from xingjiang after the first cradle last year), The plant biomass has significant correlation with branches number, branches length, node number and leaf area. In the study, we found that it has no significant correlation in the morphological traits and the SSR, EST-SSR molecular marker.Between parents and F1, It has no significant correlation alfalfa in leaf length, leaf width and leaf area leaf Perimeter and Ratio of Leaf length to Leaf width, but It has significant correlation in branch length and node number. More than 70 percent of the F1 have significant correlation or very significant correlation with their parents in branch length and node number.We analyse the biomass morphological traits and SSR EST-SSR molecular markers using cluster and DCA research, and selected 7 F1 with good quality and high, which come from 7 hybrid combinations, it provide basis for the next step of hybrid breeding. The parents which come from the 7 hybrid combinations have greater genetic distance, their hybrid are Distant hybridization. We analysed The 7 F1 alfalfa we selected using EST-SSR molecular markers, and found that the probability of appearance same two bands is 100% in 7 F1 alfalfa and 58.3% in other hybrid F1 alfalfa using primer 2 of EST-SSR, and the probability of appearance same two bands is 100%in 7 F1 alfalfa and 70.8% in other hybrid F1 alfalfa using primer 7 of EST-SSR.In alfalfa breeding, we need comprehensive analysis about morphological and molecular markers research to provide accurate detailed data, and to select hybrids with excellent traits, which full performance the heterosis of high yield and resistance to cold and drought.