07-08-2013, 01:15 PM
Effect of weather factors on severity of brown rust on different wheat cultivars.
ABSTRACT
Wheat (Triticum aestivum L.) is the world’s most extensively grown cereal crop and is staple food for over 10 billion people. It accounts for 30 per cent production amongst all cereal crops worldwide followed by rice (27 %) and maize (25 %). In India, wheat is the second most important crop next to rice with a total production of 80.58 million tonnes, grown over an area of 27.88 million hectares with a productivity of 28.91 qha-1. In Jammu and Kashmir, wheat is grown over an area of 278.30 thousand hectares with a production of 4959 thousand quintals and productivity of 17.82 qha-1 (Anonymous, 2008). The important fungal diseases that affect wheat are three rusts ( brown, stem and stripe rust), Karnal bunt, leaf blights, powdery mildew, flag smut and hill bunt. However, rust diseases cause significant damage the world over. Leaf (brown) rust caused by Puccinia recondita f. sp. tritici (Rob. ex. Desm. f. sp. tritici Eriks. & Henn.) is recognized as an important disease of wheat worldwide, causing significant yield losses over large geographical areas. The field experiment was carried out during Rabi 2009-10. Field trials on epidemiology were carried out at the University Research Farm of SKUAST-J at Chatha, Jammu. The effects of different weather factors such as average atmospheric temperature, relative humidity and rainfall on the development of brown rust were studied under field conditions on RSP-561, PBW-343 and Agra local. Epidemiological studies on wheat cultivars viz., RSP-561, PBW-343 and Agra local exhibited that there was a significant positive correlation between disease severity and minimum and maximum temperature, whereas, minimum and maximum humidity showed negative and significant correlation. The minimum and maximum temperature of 9.8oC and 19.4oC accompanied by minimum and maximum relative humidity of 84% and 87% and rainfall of 20.7 mm were found conducive for disease development. It was concluded that weather factors play an important role in disease development.