MORPHOLOGICAL AND MOLECULAR VARIATION OF PHYTOPHTHORA COLOCASIAE IN ‘SATOIMO’ TARO (COLOCASIA ESCULENTA VAR ANTIQUORUM) IN INDONESIA

Abstract

Taro leaf blight is a harmful disease caused by Phytophthora colocasiae Raciborski and has become the primary factor in damaging ‘satoimo' taro. A survey conducted in the agriculture fields of satoimo taro (Colocasia esculenta var antiquorum) in Indonesia indicated its severity disease scale between 25-50%. Morphological and molecular techniques were used to characterized the population of Phytophthora colocasiae obtained from different locations in Makassar, Maros and Gowa districts. Based on colony growth patterns, the isolates exhibited stellate and petaloid. The mean sporangial length of isolates of P. colocasiae range from 37.06  and 53.80 µm and mean width range from 22.27 and 26.90 µm. P. colocasiae are highly dynamic in nature and a considerable degree of diversity exists among them.  This provides an important basis for developing suitable control against leaf blight of taro caused by P. colocasiae based on good integrated approach. Based on the phylogenetic analysis, P. colocasiae isolates (PCEMK01 and PCEMR01) was exhibited in the same cluster with P. colocasiae strain 3 reported from India with the bootstrap of 96% at 500 replicates in MEGA 5.