Isozyme variation Areca catechu L. and allied species

Abstract

Investigations on "Isozyme variation 10 Areca catechu L. and allied species" were undertaken in the Department of Plantation Crops and Spices and the Biochemistry laboratory of the College of Horticulture, Kerala Agricultural University, Vellanikkara during the period from 2000 to 2002 with the major objectives of working out the species relationship in the genus Areca and biochemically characterizing the varieties/cultivars/types of arecanut by isozyme , analysis. .:' Twenty four arecanut accessions comprising of four species, five released varieties, 12 traditional cultivars and three exotic cultivars collected from various states were included in the investigation. The isozymes studied were peroxidase, esterase and polyphenol oxidase. The species VIZ., Areca catechu, A. triandra, A. lutescens and A. normanbyii were displayed variations with respect to the isozyme banding patterns, while no variation was observed among the five released varieties. Traditional cultivars numbering 12 had shown very little variation except in the case of TC3 and TC10. The exotic cultivars, which included two YLD tolerant accessions, had shown a striking variation when compared to other accessions of A. catechu. Based on the banding pattern of all the isozymes, the accessions were classified into eight groups. The dendrogram plotted using cluster analysis also vindicated this classification. The protein content of the accessions ranged from 3.4 to 8.8 mg/ml extract. The protein content was very high in the YLD tolerant accessions when compared to the susceptible genotypes. The activity of the enzyme peroxidase recorded a wide range of 120 - 1455 units/ml while the range of polyphenol oxidase was 22 - 208 units /ml. The activity values of peroxidase and polyphenol oxidase were very low in all the YLD tolerant lines in comparison with other accessions. High protein content alongwith low enzyme activity levels recorded invariably by all the tolerant accessions point towards a possible influence of these biochemical parameters on YLD tolerant reaction.