Studies on Epidemiology and Management of Yellow Rust of Wheat Disease Caused by Puccinia Striiformis F.sp. Tritici

Abstract

Stripe rust caused by Puccinia striiformis f. sp. tritici is one of the most destructive diseases of wheat. It is emerging as an important constraint to wheat production worldwide and specially in northern India. Host resistance is the most economical way of controlling respective pathogen. However, race-specific resistance is overcome by the evolution of new races of the pathogens. Conversely, race non-specific or quantitative resistance, controlled by many genes and effective at the adult plat stage, is generally considered more durable and long lasting. Such type of resistance is of primary interest to wheat breeders around the world. The present study was undertaken to study the influence of environmental factors on progress of disease, To evaluate stripe rust resistance in different wheat genotypes, Effect of stripe rust disease on biochemical and physiological parameters in wheat genotypes and evaluation of different fungicides and bio-agents against yellow rusty of wheat. It was found that increase in the age of the crop, increase in maximum and minimum temperature, decrease in morning and afternoon relative humidity during both the crop season was unfavourable for progression of yellow rust of wheat. It was found that eight genotypes were found resistant and twenty eight genotypes were found susceptible against yellow rust of wheat. Physiological and biochemical analysis in leaves of resistant (HD 3086) and susceptible (PBW 343) varieties revealed non-significant effect on total chlorophyll content in infected leaves as compared to healthy leaves of resistant variety. In susceptible variety, stomatal conductance in diseased leaves decreased at initial stage of infection and then reduced at higher rate at all stages of disease. In susceptible variety, the reduction in photosynthetic rate was found to be less at initial stage of disease but reduced sharply at later stages. Total phenol contents were higher in leaves of resistant variety and after infection, the total phenol content increased in resistant variety at initial stages of disease, while the decrease was less at later stage. In susceptible variety the total phenol content continued to increase at all stages of infection. Total sugar and non-reducing sugar content in both the varieties increased after infection but the increase was more in susceptible variety. Activity of Polyphenol oxidase and Peroxidase was found to be increased in resistant variety at all the stages. In resistant variety, there was significant increase in PPO and POX activity at disease initiation thereafter slightly decreased at later stages. Among various fungicides tested, Azoxystrobin 25 SC and Difenoconazole 25 EC were found most effective and controlled the disease up to 97.57 and 91.81 percent, respectively.