Genetic and phylogenetic relationships of coconut populations from Amini and Kadmat Islands, Lakshadweep (India)

Abstract

A great deal of variability exists in coconut populations of the Lakshadweep group of islands in India, which is regarded as one of the likely centre's for coconut domestication. It is possible to gain insights into the evolution of coconut populations in these islands by undertaking detailed studies of these populations. In this study, the variability and phylogenetic relationships within populations of Laccadive Ordinary Tall (LCT) and Laccadive Micro Tall (LMT) from Amini and Kadmat Islands were studied using microsatellite markers. LCT collections from these two islands were earlier grouped, according to fruit shape, into three type’s viz., elongated, round or oval shaped and pear shaped ones. Three accessions of LMT, one each from Amini and Kadmat, and a variant of LMT from Kadmat Island, characterized by the round shaped fruit and nut, were also used for the studies. Seedlings raised from these types were analysed using 20 highly polymorphic SSR markers. Elliptical type from Amini, which are described as ‘Niu Kafa’ type, emerged as distinct from other populations and was related to round or ‘Niu Vai’ type from Amini. Pear shaped type from both the islands, which was considered as the introgressed form, showed affinity and appear to have developed as a result of introgression between elliptical and round types. When the LMT palms were analyzed, the LMT palms from Amini and Kadmat clustered together, while the round variant of LMT from Kadmat Island was found to be distinct. A large extent of variations were also found among individual palms of these distinct types when analyzed using SSR markers, highlighting the importance of selection of LCT mother palms for hybrid seed production.