Molecular diversity assessment of AVRDC-The World Vegetable Center elite-parental mungbeans

Mungbean (Vigna radiata (L.) Wilczek) has been a mandate crop of AVRDC-The World Vegetable Center (AVRDC) over the past 30years. Mungbean breeding lines developed by AVRDC were released to farmers in collaborating countries and used as genetic stocks by national programs. Over 6,500 crosses have been made by AVRDC breeding program using mainly 39 parental lines. In the present study, 241 SSRs were employed to assess diversity among the parents and 5 cultivars derived from AVRDC breeding lines. Forty-eight SSRs expressed polymorphism among them. The AVRDC elite parental germplasm possesses a high genetic diversity. In the 39 parental lines, a total of 175 alleles were detected by the polymorphic SSR markers ranging from 2 to 19 alleles per marker and with PIC values ranging from 0.049 to 0.883. The polymorphic SSRs distinguished all the mungbean lines. Grouping the germplasm by UPGMA clustering based on SSR polymorphism was in general agreement with the origins and/or pedigree information. The 5 cultivars selected from AVRDC breeding lines had a moderate genetic diversity. Of the 175 alleles found in 39 parental lines, 69 alleles (39.43%) were present in the 5 cultivars. The cultivars were grouped with the Philippine germplasm and most of them were close to one of the parents in their pedigrees. Based on the results, reduction in gene diversity due to breeding among AVRDC elite parental mungbeans is not high. Yet, the diversity found in this study is relatively high as compared to those from larger collections of cultivated mungbean in the previous studies.