ASSESSMENT OF GENETIC DIVERSITY IN BANANA CULTIVARS FROM PAKISTAN BASED ON ISSR MARKERS

Abstract

Banana is a major crop grown in Pakistan but there is a lack of information on genetic diversity and purity in local cultivars, It is quite important in assisting duplication in banana cultivars. Since 1947 till 2016 banana clones were introduced, Basrai was the first clone in Sindh province due to its favorable climatic condition and fertility, later on NIGAB-1, Dhaka, Grand Naine, Fenjiao, NIGAB-3, NIGAB-2 and three cultivars of Costa Rica were successfully adapted. Diversity of banana is very important because so far it is recorded by focusing on morphological parameters rather than genomic approaches. Morphologically, sometimes it becomes very difficult to differentiate among banana cultivars due to influence of environmental factors, time consuming and expensive. So environment greatly effects phenotypic expression make it difficult to differentiate cultivars morphologically. Alternatively, DNA markers based techniques have been employed to rapidly measure the community composition based on the genetic identification of species. Present study employed inter_simple sequence repeats (ISSR) to investigate the genetic variation in local banana cultivars from Pakistan. Out of forty-five primers used, forty primers were reproducible and produced total of 260 scorable bands and 109 were polymorphic, which account to 44.57% per cent polymorphism. UBC-835 and UBC-834 detected a higher level of polymorphism in banana cultivars (86% -88%) and UBC-857 detected lowest level of polymorphism (46%). The size of DNA amplified bands ranged between (100-1500-bp). Pair-wise was calculated Jaccard’s similarity co-efficient through unweighted pair group of arithmetic mean (UPGMA) in the SAHN program of NTSYS-PC version 2.1. UPGMA identified and divided fourteen banana cultivars into two prominent and distinct groups A and B and further divided into subgroups, clusters and sub-clusters. The similarity co-efficient ranged between 0.56 - 0.88. This study indicated that at molecular level, the cultivars in group A 66% were similar with other cultivars and 34% genetically differed from other cultivars proving the broad base of germplasm. The cultivars in group B 88% similar with other cultivars and 12% variation existed among the genotype with other cultivars based on ISSR markers used. Analysis clearly revealed that ISSR can be used by the scientist to authenticate cultivar identification for domestication of banana. Key words: Banana, Genetic diversity, Pakistan, ISSR, Cultivars, Dendrogram Analysis