Construction Of Fingerprint And ID Of Banana Varieties Based On SSR Markers

In tropical and subtropical regions,banana(Musa spp.)is not only an important cash crop but also an important food crop.Banana industry is also one of the pillar industries of agriculture in China.Efficient cultivation of new banana varieties with high quality,high yield and disease resistance is the key to banana industry.Molecular marker assisted breeding can greatly improve the efficiency of breeding.At present,the biggest problem facing banana breeding is that the genetic background of germplasm resources is not clear,and the characteristics of main cultivars such as parthenocarpy,high sterility and complex genomic ploidy level make it difficult to select breeding parents.Therefore,accelerating the identification of banana germplasm resources is the basis of banana breeding.In this study,16 banana varieties were used to screen SSR primers.29 pairs of SSR primers with better polymorphism were screened according to the polymorphism,stability,band clarity and the potential of specific primers.The 29 pairs of primers were used to conduct one-generation capillary electrophoresis and two-generation sequencing-based SSR analysis for 66 banana varieties.The results of capillary electrophoresis were processed and analyzed.Sixty-six banana cultivars were clustered.The SSR fingerprint database and identity ID of 42 banana cultivars were established.The SSR marker-assisted identification based on second-generation sequencing was also explored.The main results are as follows:(1)Using 16 banana varieties,117 pairs of primers which had been published and preliminarily screened in the previous stage were further screened,and 29 pairs of SSR primers suitable for the construction of banana SSR fingerprint database were selected for the construction of banana varieties fingerprint and the development of identity ID in the next step.(2)By analyzing the data of 29 pairs of SSR primers in 66 banana varieties by capillary electrophoresis,cluster analysis showed that 29 pairs of SSR primers could effectively distinguish 42 banana varieties,and then combined with the corresponding primer genotypes of each variety,according to a certain sequence,the SSR fingerprint of banana was constructed.(3)By converting the obtained banana SSR fingerprint data into digital information,the DNA molecular identity IDs of various varieties are established,and the two-dimensional ID codes are generated to facilitate retrieval and application.(4)29 pairs of SSR primers were used for multiplex PCR amplification and second-generation sequencing analysis in 66 banana varieties,and 28 second-generation sequencing results were analyzed.Compared with the repeat units,genotypes andsensitivity obtained by fluorescent capillary electrophoresis,13 of the 24 banana varieties could not be distinguished by fluorescent capillary platforms.