Variability in Phytophthora capsici (Leonian) isolates of black pepper (Piper nigrum L.) based on nutritional preferences and isozyme profiles

Abstract

Experiments were conducted to study the intraspecific variability among five isolates of black pepper (Piper nigrum) foot rot pathogen, Phytophthora capsici, in its nutritional preferences and isozyme profiles, The carbon sources most suited for the vegetative growth of the isolates were sucrose and glucose, followed by s tarch, fructose, cellulose and maltose, Among the nitrogen sources, the L-isomers of the amino acids, glutamate, proline, aspartate, asparagine, histidine, serine, arginine and glycine, and also the organic sources of nitrogen, urea, yeast ex tract, casein hydrolysate, peptone and tryptone supported good g rowth, Among the vitamins studied, only thiamine was essential for vegetative growth of P. capsici, A considerable degree of variation was observed among the five isolates in their preferences for nutrient sources for their optimal grow the, From the isozyme profiles of esterase, acid phosphatase, superoxide dismutase and catalase systems, the similarity between the isolates ranged between 25,0%- 44,7%.