Developing Simple Sequence Repeat (SSR) Markers For Mangos

Abstract Mangos are an important tropical fruit with an abundance of species resources. SSR molecular markers have been widely used to identify and distinguish the genetic relationship of mango cultivars. The statistical results of SSR loci information in mango simplified genome sequencing show the number of dinucleotide repeat elements to be the largest, which accounts for 40% of the total SSR loci. The repetition times for each nucleotide element were mainly six. The nucleotide types of AT/AT and A/T are 17.8% and 21.2%, respectively, which accounts for 39% of total SSR. The length of SSR loci concentrated in 15bp, with 2,931 loci, which accounts for 20.12%. At the same time, the genetic diversity and phylogenetic relationship of 71 mango cultivars are analyzed. The MISA is used for searching SSR loci, designing and screening SSR primers with good polymorphism, and 20 pairs of primers are chosen following the screening of 200 pairs of primers by gel electrophoresis. The genetic diversity of mango germplasm from two different distribution areas is analyzed, and the genetic similarity coefficients are clustered by unweighted group average method (UPGMA). Genetic distance cluster analysis shows that 71 mango germplasm are divided into seven categories when the genetic similarity coefficient is 0.89, and the similarity coefficient range is 0.55 to 1, polymorphism information content (PIC) values ranging from 0.2334 to 0.7997. In summary, our findings could be used for genetic diversity analysis and the marker-assisted breeding of mango germplasm.