Abstract

Genetic relationships among 26 alfalfa cultivars, of which, 12 were of high resistance to common leaf spot (CLS), were assessed using sequence-related amplified polymorphism (SRAP) markers. 34 SRAP primer combinations were selected for fingerprinting of these cultivars and a total of 281 bands were observed, among which 115 were polymorphic (40.93%). Based on molecular data, 26 cultivars were classified into 5 groups. Group I included 12 Chinese cultivars, most of which had a low CLS resistance and were planted in cold and/or drought region in China, while 10 of 11 cultivars with a high CLS resistance were put in group II or group IV respectively. Furthermore, the clustering pattern was, on the whole, consistent with their CLS resistance or geographic origins. In addition, there was a low genetic diversity among alfalfa cultivars from China. In conclusion, SRAP markers may serve as a quick tool to analyze the genetic relationships and genetic diversity among alfalfa cultivars in conjunction with DNA-bulking method. The information produced by this study on the genetic relationships and genetic diversity among 26 cultivars could be useful to select parents in a CLS resistance breeding program of alfalfa.

Key words: Lucerne, SRAP, Medicago sativa, common leaf spot, genetic relationships