Molecular characterization of local mango (Mangifera indica L.) germplasm in Oman

Abstract

Mango (Mangifera indica L.) is an important cultivated crop in Oman, with a total of 434,788 trees scattered throughout the country. However, mango tree numbers have declined in recent decades for various reasons. Efforts to conserve this valuable resource require vast investigation of its genetic makeup. Since no molecular studies have been conducted to explore this genetic resource, the objectives of this study were to characterize the genetic diversity and structuring of mango germplasm from various mango-producing areas in Oman and to assess their phylogenetic relationship with other global cultivars. Thirteen microsatellite loci were genotyped from 318 local mango samples to assess the genetic diversity of the Omani cultivations and their phylogenetic relationship with another global cultivations. The results showed a fluctuating in heterozygosity between the Omani samples, with an average of expected and observed heterozygosities of 0.34 and 0.33, respectively, indicating a low genetic diversity. The genetic distance based on Nei's standard distance identified the Dhofar population as the most distant from all the other populations. Principal coordinates analyses (PCoA) revealed an absence of differentiation of local Omani mangoes based on geographical regions, whereas the phylogenetic analyses indicated a clear isolation of Dhofari cultivars, with some global mango samples, away from other Omani ones. This study characterized mango germplasm in Oman using molecular markers and provides a basis for further mango research and efforts for conservation.