GENETIC VARIABILITY AND MOLECULAR CHARACTERIZATION OF SOME LOCAL AND IMPORTED MANGO CULTIVARS IN EGYPT

Mango is one of the most important tropical fruits in the world. It has been cultivated in Egypt since 19th century. The usual methodologies to produce a new cultivar in Egypt are based on selection of superior seedling or importing new cultivars. To establish breeding program and improve mango cultivars, genetic variability and relationships among available mango germplasms must be detected. The present study was conducted in two successive seasons (2014 and 2015), on three common local cultivars (Ewais, Zebda and Sedeeq) and five imported cultivars (Naomi, Keitt, Fajri Klan, Tommy Atkins and Haidi) which are grown commercially in Egypt. Results revealed a wide range of variability in qualitative and quantitative characteristics of mango cultivars. On the basis of combined analysis of the two years, all fruit parameters; fruit length, breadth and weight, stone weight, TSS and acidity, showed considerably high heritability values which ranged from 80.83 to 98.27%, indicating that genetic improvement for these characters through breeding and selection would be effective. On the other hand, genetic diversity and relatedness among the eight genotypes were assessed based on fourteen decamer RAPD primers. A total of 154 bands were obtained with 81.82% polymorphism. High similarity degree was found between the local cultivar (Zebda) and the Indian cultivar (Fajri Klan) at the molecular level which was consistent with some physical characters. Results of UPGMA dendrogram revealed that the Egyptian cultivar Sedeek was the most divergent and separated in a distinct group. This was consistent with genetic relationship of pigments in peel color; Sedeek was the only cultivar that did not have yellow color in ripe fruit peel. These results indicated that RAPD analysis could be used as an effective tool in separating cultivars according to their physico-chemical properties and could be useful for genetic improvement of mango cultivars.