Responses of Local Wheat Varieties to Greenbug Schizaphus graminum and Bird-Cherry Oat Aphid Rhopalosiphum padi Infestation

Abstract

Field and laboratory studies were conducted to assess the sensitivity of 12 varieties of local wheat varieties (IPA-95, IPA-99, Abu-Ghreib, Babel-113, Bhooth-10, Bhooth-22, and Bhooth-158, Baraka, Tammuz, Fatih, Latifia and Rasheed) against infestation by Greenbug Shizaphis graminum and Bird-Cherry Oat Aphid Rhopalosihum padi in the province of Basrah. The field trial was carried out in Al-Nashwa district, county of Shatt Al-Arab, during the growing season 2019/2020. The first infestation of R. padi appeared on 9/1/2020, and reached the peak of population density on 30/1/2020, while the first appearance of S. graminum was on 17/1/2020; it reached its peak on 13/2/2020. The results of responses of local wheat varieties to the infestation of Greenbug showed that the highest average population density of greenbug was on Bhooth-158, Abu-Ghraib, Bhooth-22, and Babel-113 reaching 51.59, 17.84, 16.41, and 16.63 aphids/plant, respectively. Whereas the lowest population densities were at Fatih, Tammuz, Bhooth-10, Rasheed, and IPA-99, with averages of 8.28, 8.09, 8.87, 7.19, and 7.62 aphids.plant-1, respectively. The highest density rate of R. padi was recorded on the cultivars IPA-95 and Abu-Ghraib, with an average of 139.83 and 169.31 aphids.plant-1 respectively, while the verities Bhooth-22, Bhooth-158, and IPA-99 recorded the lowest population density rate (89.03, 99.41, and 100.25 aphids.plant-1) compared to the other varieties. The results of the chemical analysis determined the proportions of some metabolites of the local wheat varieties and their relationship to the infestation of Greenbug and showed that phenols have an effective role by reducing the population density of aphids. The verities Rasheed and IPA-99 which recorded low population rates of the aphids have the highest rates of phenols at a rate of 7 and 6.78 mg.100g-1 dry weight Also, varieties Abu-Ghraib, IPA-99, and Rasheed cultivars recorded the highest productivity rates (weight of thousand grains), with an average of 33.47, 43, and 67.42 g, respectively.