Microsatellite analysis of distinct coconut accessions from Agatti and Kavaratti Islands, Lakshadweep, India

Abstract

The Lakshadweep group of islands, located in the south-western part of India in the Indian Ocean is considered unique for its coconut populations owing to its geographic isolation and assumed introgression with mainland coconut populations along west coast of mainland India. A wide range of variability was noticed for morphological characters of Lakshadweep coconut populations. A total of nine accessions were collected from Agatti and Kavaratti Islands of Lakshadweep as part of a germplasm enrichment programme for island coconut populations of India. This includes three Laccadive Micro types, four types of Laccadive Ordinary Tall differing in nut bearing habit, fruit shape and size, one each of sweet husked Kaithathali tall and dwarf type. The microsatellite analysis of the 9 coconut populations with 8 primers revealed a total of 37 alleles. The highest number of eight alleles was detected for the CAC8 primer and the lowest number of three alleles for the CAC10, CAC13 and CnCIRG11 primers. The estimate of heterozygosity was highest (>0.5) for the two Laccadive Micro Tall (LMT02 and LMT03) and the Laccadive Small Tall (LCT02) populations and was lowest (0.24) for the Laccadive Micro Tall (LMT01). The sporadic occurrence of Laccadive Micro Tall is discussed in the context of high outcrossing and inbreeding depression.