Evaluating genetic diversity among arecanut (Areca catechu L.) cultivars through morphological and molecular analysis
Abstract
Arecanut ( Areca catechu L.) is a vital cash crop in South and Southeast Asia, supporting millions. Despite its cultural, medicinal, and economic importance, widespread chewing by ~600 million people makes it the fourth most consumed addictive substance. Its cultivation is threatened by diseases (Fruit rot, crown rot, crown choking, Foot rot, yellow leaf disease and inflorescence dieback) and pests (spindle bug, root grub, inflorescence caterpillar, and mites), reducing yields. This necessitates exploring genetic diversity in arecanut germplasm. Our research evaluated the genetic variability of ten cultivars using morphological and molecular markers. Variance analysis showed significant genotype variation for all characters. High PCV, GCV, heritability, and genetic advance as a percentage of the mean were noted. Higher PCV and GCV were seen for yield (81.3% and 79.7%), dry husk weight (69.9% and 67.8%), and fresh kernel weight (65.1% and 64%). Heritability ranged from 13.2 to 99%. These characters are influenced by additive gene action, useful for genetic improvement. D 2 analysis grouped cultivars into four clusters. The molecular diversity cluster was divided into two major clusters and RAPD, ISSR, and RGP DNA markers showed polymorphism percentages of 60%, 66.8%, and 65.8%. PIC values ranged from 0.43 to 0.79, averaging 0.65 for RAPD, 0.56 to 0.77, averaging 0.68 for ISSR, and 0.54 to 0.74, averaging 0.64 for RGP. The highest PIC value was OPBA20 at 0.79. Comparing phenotypical and genotypical observations, genotypes Keladi Local, Thirthahalli Local, Sagar Local, SAS-1, and Sringeri Local clustered together, while Sumangala, Sreemangala, and Mohithnagar formed another cluster. Hirehalli Dwarf and Mangala formed a single cluster. Using morphological and DNA markers is the most comprehensive approach to analysing genetic diversity. Identifying divergent genotypes is crucial for recombinant breeding, as these hold potential for heterotic recombinants.