GENETIC DIVERSITY OF WILD AND CULTIVATED MANGO GENOTYPES OF PAKISTAN USING SSR MARKERS

Mango (Mangifera indica L.) is one of the most important fruit crops cultivated in tropical and subtropical regions of the world. It is commercially cultivated in about 103 countries of the world. Global production of mango has been estimated to be 40 million tonnes, out of which Pakistan shares 4.5% (FAOSTAT, 2015). Pakistan is ranked sixth in the world after India, China, Thailand, Indonesia and Mexico (FAOSTAT, 2015). Pakistani mangoes have gained popularity in the world due to their high nutritive value, attractive colour, smooth texture, excellent flavour and fine aroma (Ullah et al., 2012). Being the center of origin and diversity, Indo-Pak subcontinent has broad history (more than 4000 years) of mango cultivation (Ravishankar et al., 2000). There are almost 260 mango varieties reported in Pakistan, among them ‘Samar Bahisht Chaunsa’, ‘Sufaid Chuansa’, ‘Kala Chaunsa’, ‘Anwar Ratole’, ‘Fajri’, ‘Sindhri’, ‘Dusehri’, ‘Faiz Kareem’ and ‘Langra’ are commercially important (Amin and Hanif, 2002). Currently mango cultivars, ‘Sindhri’, ‘Samar Bahisht Chuansa’ and ‘Sufaid Chaunsa’ are being exported to Middle East, Southeast Asia, EU and USA (Nafees et al., 2013). These mango genotypes are heavily threatened by poor orchard management practices, alternate bearing, various diseases, insect pests and physiological disorders, which affects production and export volume (Rajwana et al., 2008). Rich diversity present in indigenous wild germplasm offers a scope to find promising varieties having regular bearing with long shelf-life. But, this indigenous mango germplasm is depleting in their natural habitats and there is a dire need to collect, conserve and utilize this enriched source of diversity. It is imperative for the maintenance of genetic variability, the resistance to genetic erosion (Cunha et al., 2009) and introgression of economically important traits to sustain productivity and survival under changing climatic conditions. Characterization and selection from existing germplasm also offers a plausible way of improving genotypes with desirable traits. Azad Jammu and Kashmir region of the country is blessed with wide range of indigenous seedling mango germplasm. This germplasm varies in fruit size, fruit colour, bearing habits, flavour, taste, juiciness, ripening time, and texture (Khan et al., 2015; Khan et al., 2016). These seedling mango trees with desirable traits can be served as a novel source for future crop improvement and sustainable mango production (Singh and Jawanda, 1962; Ravishankar et al., 2000). Moreover, wild mango germplasm is not only a source of genetic variation but also possesses tolerance against different pathogens. It can also be used to widen the genetic base of cultivated mango varieties along with offering a scope to extract desirable genes and their utilization in mango improvement and breeding programmes. So, compiling the DNA fingerprints to analyze and document the genetic landmarks can probe the evolutionary relationship between wild and cultivated populations. Pak. J. Agri. Sci., Vol. 55(1), 83-93; 2018 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 DOI: 10.21162/PAKJAS/18.6360 http://www.pakjas. com.pk