Microsatellite (SSR) marker assisted assessment of population structure and genetic diversity for morpho-physiological traits in guava (Psidium guajava L.)

Twenty-four SSR markers were utilized to evaluate the genetic variation across thirty-six guava varieties including wild species. The SSR markers revealed a polymorphism of 95.7% and a great range of diversity among the experimental guava germplasm. Eighty-one alleles were detected, in diversity analysis, with 2-7 alleles with a mean of 3.682 alleles per loci. The SSR loci showcased an allele frequency of 0.306 (mPgCIR251) to 0.861 (mPgCIR227) at a mean value 0.561. An average polymorphic value of 0.490 across was measured for all the 36 germplasm with the range of 0.234 in mPgCIR227 to 0.706 in mPgCIR03. The genetic diversity for SSRs varied between 0.248 (mPgCIR227) and 0.747 (mPgCIR03) with an average of 0.548. Clustering of germplasm distinctly separated pink and white flesh germplasm into two major groups. First three coordinates contributed towards 32.76% of the variation measured using principle coordinate analysis. Molecular variance (AMOVA) study showed 06 and 94% genetic variation among population and individual, respectively with five sub populations. This study provides valuable information for understanding the genetic variability in guava which can be exploited to develop varieties with better fruit yield and nutritional quality.