Genetic relationship and diversity among coconut (Cocos nucifera L.) accessions revealed through SCoT analysis.

K E Rachana,Anitha Karun,B A Jerard,A A Sabana,Shafeeq Rahman,M K Rajesh

doi:10.1007/s13205-015-0304-7

Abstract

Coconut (Cocos nucifera L.) is one of the important palms grown both as a homestead and plantation crop in countries and most island territories of tropical regions. Different DNA-based marker systems have been utilized to assess the extent of genetic diversity in coconut. Advances in genomics research have resulted in the development of novel gene-targeted markers. In the present study, we have used a simple and novel marker system, start codon targeted polymorphism (SCoT), for its evaluation as a potential marker system in coconut. SCoT markers were utilized for assessment of genetic diversity in 23 coconut accessions (10 talls and 13 dwarfs), representing different geographical regions. Out of 25 SCoT primers screened, 15 primers were selected for this study based on their consistent amplification patterns. A total of 102 scorable bands were produced by the 15 primers, 88 % of which were polymorphic. The scored data were used to construct a similarity matrix. The similarity coefficient values ranged between 0.37 and 0.91. These coefficients were utilized to construct a dendrogram using the unweighted pair group of arithmetic means (UPGMA). The extent of genetic diversity observed based on SCoT analysis of coconut accessions was comparable to earlier findings using other marker systems. Tall and dwarf coconut accessions were clearly demarcated, and in general, coconut accessions from the same geographical region clustered together. The results indicate the potential of SCoT markers to be utilized as molecular markers to detect DNA polymorphism in coconut accessions.

Highlights

Coconut (Cocos nucifera L.), belonging to the family Arecaceae, is the only reported species under the genus Cocos
The results indicate the potential of start codon targeted polymorphism (SCoT) markers to be utilized as molecular markers to detect DNA polymorphism in coconut accessions
A thorough knowledge on genetic relationships among coconut accessions is needed for adopting effective conservation strategies, germplasm utilization and management of Biotech (2015) 5:999–1006 coconut genetic diversity studies for quite some time

Summary

Introduction

Coconut (Cocos nucifera L.), belonging to the family Arecaceae, is the only reported species under the genus Cocos. Tall (‘typica’) and dwarf (‘nana’) are two main categories of coconut palms. The Talls are naturally crosspollinating types, have more economic value, are vigorous growing, comparatively late to flowering and the fruits are with intermediate colors of brown, green, yellow, orange among individual palms. In contrast, are naturally self-pollinating types with reduced growth habitat, early flowering and produce large number of medium to small, distinctly colored (green or yellow or orange or brown) fruits (Dasanayaka et al 2009). Many efforts are ongoing in coconut-growing countries to conserve the rich natural diversity existing in coconut germplasm collections for further utilization in crop improvement programs so that it becomes a more profitable crop for small-farm holders, who constitute the vast majority of coconut growers

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Results

Conclusion