Identification Of Common Bean Germplasm Resources Based On Phenotype And SSR Molecular Markers

Serious confusion was occurred on common bean varieties in the current market and this seriously restricts the development of common bean industry.This was mainly caused by the frequent exchange of varieties between different regions and the lack of a unified naming standard.Identified common bean character is of great significance for the identification of germplasm,purification and protection of the rights of new varieties.In this study,243 samples of common bean resources were identified by using phenotype and SSR molecular marker.Ntsys2.10 software was used to calculate the genetic similarity coefficient of Germplasm by using UPGMA method,and the cluster analysis chart was drawn.The genetic relationship and authenticity were identified,and the biological identity card of common bean resources was constructed.The main results are as follows:(1)27 phenotypic traits of common bean were investigated in the study.The diversity index of 27 phenotypic characters is 0.08 to 2.15 with an average of 1.33,and the pic is 0.03 to 0.86 with an average of 0.66.The trait with the highest polymorphism information content and diversity index is grain color,while the lowest one trait is leaf shape.UPGMA clustering analysis showed that the similarity coefficient of germplasm materials was between 0.80 and 0.97,243 bean varieties were divided into eight groups at the similarity coefficient of 0.82.(2)32 common bean phenotypic characters in two different regions were analyzed.16 phenotypic characters were screened out which were less affected by the environment.On this basis,243 common bean resources were analyzed by using UPGMA cluster analysis,and the similarity coefficient between germplasm materials was 0.75 to 1.00.Five groups can be divided when the similarity coefficient was 0.79,however 67 resources can't be distinguished.(3)18 pairs of primers with high polymorphism,good repeatability and high band definition were screened out to identify the germplasm resources of common bean.There are 58 alleles in SSR primers,with an average of 3.22 markers detected in each pair;the number of effective alleles(NE)is between 1.30 and 4.23,with an average of 2.63;the Shannon index variation range is between 0.57 and 1.37,with an average of 0.92;the polymorphism information content(PIC)is significantly different,with an average of 0.61,indicating that the selected primers have good identification ability.UPGMA clustering analysis showed that the similarity coefficient between germplasm materials was between 0.56 and 1.00,and when the similarity coefficient was 0.61,the germplasm materials could be divided into six groups,six varieties could not be distinguished.(4)Comparing the cluster results SSR markers and phenotypic traits,it was found that the results of the two were similar,but there were significant differences in genetic similarity and variety identification.176 germplasm resources can be distinguished by 16 phenotypic traits that are less affected by the environment,and 67 can't be distinguished.There are 237 germplasm resources that can be distinguished by SSR,and 6 germplasm resources that can't be distinguished by SSR.Based on the analysis of two above methods,it can be concluded that there is no significant difference in the phenotype and SSR markers of bean varieties No.7(black kidney bean Y120)and No.32(black kidney bean Longjiang)and No.122(long kidney bean 5)and No.187(long kidney bean 5 Y2),which can't be distinguished by phenotype and SSR markers,so it can be preliminarily inferred that they are synonyms;No.53(milk kidney bean)and No.173(milk kidney bean)could not be separated by SSR markers,but there was a slight difference in the color.It was preliminarily concluded that the material No.53 or No.173 had a color mutation in the same material.The results of SSR and phenotype clustering are not same,but they can complement each other,and distinguish some varieties which can't be completed by one mmethod.The combination of the two methods can effectively improve the accuracy for identifying common bean varieties.Based on the combination of phenotype and SSR molecular markers,18 pairs of primers were combined with a certain order and the assignment and description of phenotype characters were added to construct the biological identity cards of different common bean germplasm resources.