Asian Research Thesis Index

Abstract

Potato leaf roll virus is an important and serious threat to successful potato production. It is transmitted by aphid M. persicae in a persistent manner. Multiple regression predictive models were developed on five years data of PLRV disease incidence and epidemiological factors. The model was validated by another regression model based on two years data. The two models showed 77% and 74% disease variability in the PLRV disease development respectively. Minimum temperature, relative humidity and rainfall were appeared to be most contributing factors in the PLRV disease development Similarly aphid population predictive models were developed on five and two years data. The models explained 61% and 64% variability in the aphid population development respectively. Minimum temperature and relative humidity contributed towards the development of aphid population. There was significant correlation of maximum, minimum temperature and relative humidity with PLRV disease incidence. The aphid population had significant correlation with PLRV disease incidence during few years. Only maximum and minimum temperature significantly correlated with the development of aphid population. PLRV disease incidence increases with increase in the maximum and minimum temperature and decreases with the increase in the relative humidity. Forty varieties/lines/clones were screened under field conditions to identify resistance against PLRV. ELISA was the criterion to confirm the virus infection. AUDPC was calculated to quantify the disease resistance during two years of trial. Astrix, Orla, Oceana and Mirrato, Hermes, Safreen and 396266-33 appeared to be highly resistant. Five treatments were applied in combination with salicylic acid to control the PLRV disease and its vector. The results revealed that all the treatments significantly reduced the PLRV disease incidence and aphid population as compared to the control. Exogenous application of salicylic acid alone and in combination with other treatments reduced the PLRV disease incidence significantly as compared to the control. The most effective treatment was salicylic acid + acetameprid against the aphid M. persicae and PLRV disease.

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