Systematical Evaluation On Alfalfa Germplasm And Genetic Diversity Analysis

Alfalfa is an important forage legume, it plays an important role in animal husbandgry. There were relatively abundant alfalfa germplasm resources in China. By research on alfalfa morphology, agronomic traits, resistance and persistance and DNA molecular marker we will make out the genetic relationship of alfalfa germplasm; establish the evaluation system of alfalfa germplasm; find the elite alfalfa germplasm;which it has an important significance for further identify alfalfa germplasm resources and breed new varieties.This study was conducted to assess 57 Chinese alfalfa varieties (lines/wild accession) in aspects of morphological and agricultural traits, resistance to cold,drought and rust disease, persistence and genetic diversity using molecular markers (RAPD, AFLP, SSR, EST-SSR).The results showed as follows:1.There were differences in morphological and agricultural traits, resistance to cold drought and rust disease, persistence and genetic diversity in Chinese alfalfa varieties/lines from the views of varieties types and 3 species (M.sativa,M.falcata and M.varia).There was no distinct traits of Chinese alfalfa varieties, and 57 Chinese alfalfa varieties classified into 4 yield types and 4 regrowth types;5 drought resistance grades and 5 rust resistance grades. Chinese alfalfa varieties standard checks for evaluating drought resistance and rust resistance were put forward.2.There was correlation between morphological traits and agricultural traits in selected alfalfa plants: there were positive correlation between yield and leaf shape factor, regrowth rate,leaf area and leaf lenghth; positive correlation between regrowth rate and leaf width, leaf area, leaf lenghth, leaf perimeters, but negative correlation between regrowth rate and inter-nod number. Analysis on correlation among alfalfa varieties/lines also showed there was positive correlation between yield and regrowth rate, leaf width and leaf shape factor, which indicated that the regrowth rate and leaf shape factor will be as selected index in alfalfa yield breeding.3.The fingerprintings have not been established for distinguishing Chinese alfalfa varieties. but the fingerprintings were established for distinguishing 25 alfalfa individual plants Using RAPD(Primer S20,S146,S52,S311,S156), SSR primers afctt1 and EST-SSR primers aw695584 ,which could clearly distinguish alfalfa individual plant from 25 plants.4.There was rich genetic diversity in Chinese alfalfa, The analysis using RAPD and AFLP showed there was 70.54%, 69.96% variation among varieties /lines,29.46% ,30.34% variation between varieties/lines respectively, The data showed more genetic diversity between varieties/lines than measured by seed protein and iso-enzyme, which methods will lowly value the alfalfa varieties/lines gene divergence than using the RAPD and AFLP.5.The analysis on seedling morphological traits showed the distance between cotyledon and 1st leaf were not all increasing with fall dormancy rising, It is difficult to detect the differences among low fall dormancy group, because the distance is too short . there were significant differences between different fall dormancy groups, but there were no significant differences in alfalfa cultivars among fall dormancy groups; some varieties with higher fall dormancy, but with lower the 1st leaf to cotyledon distance; which suggested that the 1st leaf to cotyledon distance could be used as index to estimate alfalfa fall-dormancy in which group, but could not be used as index to measure fall dormancy accurately.