Pathogenic variability of Pseudoperonospora cubensis in Gangetic Alluvial region of West Bengal, India

Abstract

Cucurbits are tremendous economically important vegetable crops and extensively cultivated in tropical and subtropical part of the world during both rainy and winter seasons. Biotic stresses are of paramount importance in causing economic losses in cucurbits. Downy mildew, a foliar disease caused by an Oomycetes, Pseudoperonospora cubensis (Berk. & Curt.) Rostow, is one of the most destructive pathogens of cucurbits especially in wet and temperate regions, with worldwide distribution. Isolates of pointed gourd and ivy gourd showed no symptoms with most of the cucurbits hosts except pointed gourd and ivy gourd. P. cubensis isolate of pointed gourd differed from other isolates and may belong to different pathotype. The results of this investigation suggest that high variability of P. cubensis in terms of different pathotypes exists in the Gangetic Alluvial Region of West Bengal. Based on morphological characterisation, nine isolates of P. cubensis are grouped into four clusters by using hierarchical cluster analysis.

Keywords:

• P. cubensis
• downy mildew
• cucurbits
• pathogenic variability

Acknowledgement

The authors gratefully acknowledge the Indian Council of Agricultural Research, New Delhi, India, for providing financial assistance under the National Fund for Basic and Strategic Research to carry out the research programme.