Diversity in Melon (Cucumis melo L.) Landraces of Karnataka State of Southern India for Downy and Powdery Mildew Disease Resistance

Abstract

We present here the report on evaluation of melon landraces from the Karnataka state of India for resistance to downy mildew (Pseudoperonospora cubensis) and powdery mildew (Podosphaera xanthii), the major diseases of melon as well as other cucurbits. Thirty four melon landraces collected from different agro-climatic regions of the state were evaluated for resistance against downy mildew under natural epiphytotic conditions and powdery mildew under artificial conditions. Percent disease index (PDI) was calculated for each entry and based on that accessions were categorised as resistant, moderately resistant and susceptible. A very wide variation was observed among the accessions for resistance to both the diseases. Based on PDI, out of 34 accessions, COHB04, COHB37, COHB38, COHB41 and COHB43 were resistant to downy mildew. Ten genotypes were moderately resistant, fifteen were susceptible and four lines including susceptible check were highly susceptible to disease. Three landraces, COHB12, COHB38 and COHB40 were resistant to powdery mildew disease. Two genotypes were moderately resistant and rest of the lines were susceptible to disease. COHB38, an unexplored and uncultivated genotype was resistant to both the diseases. The highly resistant genotype COHB38 identified within the accessions tested offers an additional source for the development of downy and powdery mildew resistant melon cultivars.