| Adzuki bean(Vigna angularis(Willd)Ohwi & Ohashi)originated in China and is a cultivated species of the genus Vigna with a genome of 2n=22.Adzuki bean is an important edible legume crop in my country with abundant germplasm resources.By 2008,the national genebank has kept nearly 5,000 copies,but the source is relatively complicated,and there are a large number of "same-named but different species" and "multiple-named" specie.Adzuki bean has been included in my country’s agricultural plant variety protection list.In recent years,new varieties’ number of applications for protection has been increasing.However,adzuki bean breeding parents are relatively single,and a small number of backbone parents are reused,resulting in a gradually narrowing genetic background among existing varieties.For one thing,adzuki bean has not been included in the registration catalog of non-major crop varieties.For another the lack of market access management,and the low awareness of intellectual property protection of adzuki bean breeders are not conducive to the long-term development of breeding.Based on SSR molecular markers,this article establishes a rapid and accurate identification system for adzuki bean varieties,which can accurately screen similar adzuki bean varieties in the Distinctness,Uniformity and Stability test(DUS test for short)and which helps strengthen the supervision of the adzuki bean seed market.The main results of this study are as follows:1.The establishment of Adzuki bean SSR molecular marker identification technology system and variety fingerprint database.Firstly,28 pairs of SSR core primers with clear bands,good stability and high polymorphism were screened out.The PIC value of the core primers ranged from 0.246 to0.877,with an average of 0.583.A total of 245 alleles were detected in 182 adzuki bean varieties.The range of allelic variation is 2-20,and 8.75 allelic variation is detected for each pair of primers on average.An adzuki bean variety identification technology system based on SSR markers was established,and a DNA fingerprint database of 182 adzuki bean varieties was constructed.2.The analysis of the genetic diversity of 182 Adzuki bean varieties.The genetic analysis of 28 pairs of core primers on 182 adzuki bean varieties from different geographical sources showed that the genetic distance between the varieties was between 0 and 0.911,with an average of 0.619.The cluster analysis results based on Nei’s genetic distance show that 28 pairs of core primers can distinguish 173 adzuki bean varieties,and all tested varieties can be divided into three groups.From the molecular clustering results,molecular-based genetic distance division the geographic origin of varieties is relevant.3.Evaluated the feasibility of SSR fingerprint database to assist in screening similar varieties for DUS testing.Field planting comparison and identify 8 varieties that could not be distinguished by molecular fingerprints showed that there was no significant difference in phenotypic traits between the varieties within the group,and the varieties between the groups could be distinguished from each other.According to the definition of breed,these indistinguishable breeds may be "sisters" or "multiple names of one variety".The molecular identification results are consistent with the phenotypic identification results,verifying that this set of primers is suitable for assisting screening of similar species in the DUS test and avoiding duplication of authorization. |
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