Genetic and Phenotypic characterization of Phytophthora colocasiae in Taro Growing Areas of India

Abstract

Phenotypic and molecular methods were used for characterizing 40 Phytophthora colocasiae isolates obtained from Andhra Pradesh, Assam, Kerala, and Odisha regions of India over a period of five years. Phenotypic parameters such as virulence, colony morphology and mating type varied among isolates collected from different regions over the years. No correlation was observed between phenotypic parameters of the isolates and their geographical origins. Considerable inter and intra specific variation were detected by random amplified microsatellites (RAMS) analysis with 100% polymorphism among the isolates. Dendrogram constructed based on RAMS data using the unweighted pair group method with arithmetic mean (UPGMA) grouped the P. colocasiae isolates into two major clusters. No relationship was obtained between RAMS groups of the isolates and phenotypic characters/geographical origin. Population genetic analysis showed that P. colocasiae isolates were highly diverse among different regions. Analysis of molecular variance (AMOVA) showed that most of the genetic variability in P. colocasiae was confined to within a population (93.21%). These results indicate that P. colocasiae populations in India are highly diverse and care should be taken in developing disease management programmes or in breeding resistant cultivars.