Genetic diversity analysis of promising Ceylon olive (Elaeocarpus serratus L.) genotypes using morphological traits and ISSR markers

Ceylon olive (Elaeocarpus serratus L.) is a fruit tree indigenous to Sri Lanka. Due to lack of information on genetic diversity and germplasm wealth, the tree remains underexploited. Therefore, diversity assessment both through morphological and ISSR markers, was undertaken. As a result of extensive field exploration survey among 150 trees, 25 accessions superiority in fruit weight were selected and designated as Candidate Plus Trees (CPTs). Morphological traits including 24 quantitative and 10 qualitative were evaluated for three consecutive years, and morphological characteristics among the CPTs in fruit characteristics viz; fruit length, fruit sphericity and fruit surface area revealed significant variations. Principal Co-ordinate Analysis distinguished CPT14 from all other CPTs, possibly due to its distinctiveness of leaf and fruit traits. Further to ensure the observed variations could be genetic ISSR profiling of CPTs was performed using 23 UBC primers. Out of 144 fragments scored, 113 bands were polymorphic and estimated RP, PIC and MI of specific primers (UBC 810, UBC 811, UBC 834 and UBC 873) was high, thus proved usefulness in discriminating within the species level. Cluster diagram constructed on UPGMA based similarity matrix of ISSR profile showed 25 CPTs were 88 % of similarity and remaining divergence attributed by the superior morphological as well as genetic traits. Tree to tree variability in fruit characteristics exist among the 25 CPTs and has effectively discriminated by ISSR markers. Further, the superior germplasm CPT14, found to have distinct morphological features with distinguishable ISSR profile. This germplasm can be further used for cloning and improvement programs.