关键词: 木瓜属, 品种, SRAP, 遗传多样性

Abstract:

【Objective】 The botanical source, genetic relationship, and genetic diversity of Chaenomeles cultivars were probed. The aim is to provide a scientific basis for Chaenomeles cultivars classification. 【Method】 The cluster analysis, principal coordinate analysis and genetic diversity of 27 cultivars of Chaenomeles and 5 wild species were analyzed using 22 SRAP primer combinations.【Result】 A total of 152 polymorphic loci were detected among these materials with average 6.91 polymorphic loci per SRAP primer combination, and the percentage of polymorphic loci was 73.08%. The result of cluster analysis revealed that 32 materials could be divided into 4 groups, namely C. cathayensis system, C. thibetica, C. speciosa system and C. japonica system. C. thibetica appeared to be rather closely related to C. cathayensis system. C. japonica system and C. speciosa system clustered into together. C. japonica system and C. cathayensis system were the most distantly related systems. C. speciosa system took an intermediate position between C. japonica system and C. cathayensis system. Genetic diversity analysis showed that C. japonica system and C. speciosa system were more diverse than C. cathayensis system. Differences in mating and breeding systems among the species can be suggested as a possible explanation of the results. At the genus level, the coefficient of genetic differentiation among species (GST) was 0.4969. 【Conclusion】 SRAP molecular markers was an effective research tool for genetic relationship of Chaenomeles cultivars. Integrated morphological characters and SRAP analysis, the state of basal style hairiness was one of the accurate indicators for identification of botanical source of Chaenomeles cultivars. C. × superba was closely related to C. speciosa, and could be used as a cultivar group in C. speciosa.

Key words: Chaenomeles, cultivar, SRAP, genetic diversity