Potato Journal
  • Year: 2005
  • Volume: 32
  • Issue: 1 and 2

Comparative aggressiveness of metalaxyl resistant and sensitive isolates of Phytophthora infestans

  • Author:
  • P.H. Singh1, B.P. Singh2, Lokendra Singh3, Jhilmil Gupta4
  • Total Page Count: 5
  • Page Number: 61 to 65

1Central Potato Research Institute, Shimla 171 001, HP, India

2Central Potato Research Institute Campus, Modipuram 250 110, Meerut, UP, India

3Meerut College, Meerut 250 001, UP, India

4Hamco Enterprises, Mahavir Ganj, Aligarh 202 001, UP, India

Abstract

Data on comparative growth rate, zoosporangial germination and aggressiveness of metalaxyl resistant (MR) and metalaxyl sensitive (MS) isolates of P. infestans collected from different parts of the country revealed that MR isolates excelled MS isolates in all respects. The MR isolates showed higher growth rate than the MS isolates on rye agar media. Zoosporangia of MR isolates were more efficient in germination as compared to those of MS isolates. Further, zoosporangia from MR isolates having 100, 50, 25 and 10 ppm tolerance exhibited 87%, 72.8%, 64.1% and 56.6% germination, respectively as compared to 43.3% germination for MS isolate. MR isolates also showed more aggressiveness and competitiveness when compared with MS isolates using composite fitness index (CFI). 100 ppm tolerant isolate showed highest aggressiveness (CFI-72429) followed by 50 ppm (CFI-71459) and 25 ppm (CFI-49339) isolates.