Genetic Diversity Analysis And Establishment Of Pre-core Collection Of Mungbean[Vigna Radiate(L).Wilczek] Germplasm In China

Mungbean (Vigna radiate)is planted extensively in China and there are abundant Chinese mungbean germplasm resources. However, as a minor crop in China, mungbean has been lagged in its genetic studies, compared with rice, wheat, maize and soybean. In this study, we assessed the genetic diversity of the total of 5072 accessions of Chinese mungbean resources, and established a pre-core collection with an optimal sampling method. A set of polymorphic PCR markers were also selected for further analysis of these germplsam resources. The aims are to give an efficient utility of mungbean germplasm and to accelerate the genetic study of this crop. The main results were as follows:1. Most of the Chinese mungbean germplasm distribute between latitudes 29～41°N and longitudes 107—123°E. The area with higher genetic diversity index was between latitudes 35—37°N and longitudes 111—115°E, 37—39°N and longitudes 111—115°E, 39—41°N and longitudes 115—119°E, 41-43°N and longitudes 115—119°E, so it was assumed that the genetic diversity center was between 35—43°N and 111—119°E.2. Based on 14 agronomic traits, 13 sampling strategies were used to establish the pre-core collections of mungbean germplasm. The results indicated that selection based on clustering was better than random selection, stratified according to traits was better than to geographical distribution, genetic diversity-dependent strategy was better than square root and proportion strategy in determination of sampling number. Finally, an optimal strategy was set by stratified according to traits, determination the sampling number with genetic diversity-dependent strategy, and then selected sample within clusters. By using this method, a pre-core collection of Chinese mungbean germplam with a total of 719 accessions was established. The pre-core carry 100% phenotypic genetic diversity of the whole collection.3. Twelve mungbean accessions with different agronomic traits were used to screen polymorphic PCR markers that were obtained from mungbean, adzuki bean (Vigna angularis), cowpea (Vigna unguiculata) and common bean (Phaseolus vulgaris). The results showed that SSR from mungbean had the highest producing rate (85.4%), while the SSR from common bean was the lowest (37.5%). In total, we obtained ten pairs of polymorphic primer pairs that could be used for genetic analysis of mungbean germplasm, eight of them are from mungbean, one is from cowpea, and one is from common bean. In total of 47 alleles were detected among 192 accessions by using these primers. Further analysis suggested that all the accessions were divided into 2 groups (north accessions and south accessions) by based on the molecule data.