Peach (Prunus persica) is an important fruit crop worldwide with several thousand cultivars. Cultivar discrimination and hybrid authentication are often required in peach breeding and can be achieved by applying various molecular markers including simple sequence repeat (SSR). In this study a total of 2146 expressed sequence tag (EST)–SSR loci were detected with the 10,737 EST sequences retrieved from the NCBI. A total of 49 EST-SSR markers, including 24 simple ones with a motif comprising of tri-, tetra-, penta-, hexanucleotides, and 25 compound ones, were selected and then primers were designed. Following conventional polymerase chain reaction (PCR) specificity control and sequence authentication, as well as fluorescence-based PCR product size and stutter band evaluation, 37 EST-SSR markers with correct amplification and without stutter band interference were validated. Among them, 14 were polymorphic in 18 closely related peach accessions, with polymorphism information content (PIC) ranging from 0.0994 to 0.3750. The 18 peach accessions can be distinguished using nine polymorphic markers, with the exception of ‘Shangshandayulu’ and ‘Xipu 1’, both being bud sports from ‘Yulu’. The clustering of the accessions as well as the fingerprint profiles supported the authentication of the hybrids. These EST-SSR markers are useful for peach breeding research.
Maomao Ding, Ke Wang, Wenting Wang, Miaojin Chen, Dajun Wu, Changjie Xu and Kunsong Chen
Wenting Wang, Chao Feng, Zehuang Zhang, Liju Yan, Maomao Ding, Changjie Xu and Kunsong Chen
Chinese bayberry (Morella rubra) is an economically important subtropical evergreen fruit crop native to China and other Asian countries. For facilitating cultivar discrimination and genetic diversity analysis, a total of 38 high-quality and highly polymorphic expressed sequence tags-simple sequence repeat (EST-SSR) markers, with little or no polymerase chain reaction (PCR) stutter bands, including 21 screened from those obtained previously and 17 newly developed markers, were developed. The average number of alleles (N a) per locus was 5.6, and polymorphism information content varied from 0.34 to 0.86, with a mean value of 0.57. With these markers, all 42 Chinese bayberry accessions analyzed were successfully discriminated and the phylogenetic relationship between accessions was revealed. The accessions can be separated into two groups with six subgroups. The grouping of four main cultivars in three subgroups and 12 white-fruited accessions, each with little or no anthocyanin accumulation in ripe fruit, into five subgroups suggested the preservation of broad diversity among cultivated populations. These EST-SSR markers and the findings obtained in this study can assist the discrimination of cultivars and lines and contribute to genetic and breeding studies in Chinese bayberry.