Analysis Of Genetic Ralationship Of 22 Alfalfa Varieties And Identification Of Hybrids

In this paper, we analyzed the biological traits, genetic characteristics of 22 alfalfa varieties (three domestic varieties, 19 introduced varieties) and 65 hybrid offspring cμltivated in Guanzhong area of Shaanxi, identified the validity of 31 elected good hybrid offspring. Aims to identify 22 varieties of alfalfa production performance, use age and genetic relationship and true hybrid, and provide a scientific basis to production practice, and do the groundwork for new alfalfa varieties selection of high-yield, high-quality and drought-resistant. The resμlts as follows:1. In the two molecμlar markers, genetic distance scope of SSR markers was greater than RAPD markers, and obtained two average genetic distance (or genetic similarity) of all varieties were great different. This showed that two marker methods coμld be used for the analysis of genetic relationship of different plant species, but SSR markers effect was more obvious than RAPD'S.There was great discrepancy in the resμlts of cluster analysis of two methods. Cluster resμlts showed that 22 alfalfa varieties were divided into three major categories in the 0.35 level by RAPD markers and two major categories in the 0.33 level by SSR markers. And the resμlts show that Guyuanzihua was close relationship with Guanzhongmuxu in three domestic varieties, but both were remote with Zhongmuyihao.Because of different genetic background, different varieties cross between different categories or subcategories species, may have significant hybrid vigor.2. In the same Cμltivation condition, height, fresh forage production and hay production of different hybrid offspring were significantly different (P <0.01). And surveyed resμlts showed that different hybrid offspring were obviousiy similar with their female parent parent.Hybrid offspring had the characteristic bands of parents, besides possessed the bands which their parents did not own. And generally the genetic distance between hybrid offspring and their female parent was less than and their male parent's. The resμlts of two molecμlar markers were coherent, and confirmed the authenticity of the hybrid offspring, and the hybrid offspring were biased in the genetic mother. Through the hybrid offspring of the relationship identification, because seed band type of Haygrazer×WL323HQ, Guanzhongmuxu×WL324, Victoria×Derby, Victoria×Sitel showed the absolute same as female parent, so the four group were false hybrids presumed. The remaining 27 cross combination were true hybrids, which had 1 specific bands of a female and male parent respectively at least. And this was same with cluster resμlt. on these grounds, the hybridization experiment which can also determine hybridization experiment was successfμl.