22 Ara 2024 Pazar
Laboratory assessment of host plant resistance of different wheat varieties to the English grain aphid, Sitobion avenae F. (Homoptera: Aphididae) at the stem elongation growth stage
Abstract :The English grain aphid is regarded as one of the most important pests of small grain cereals, especially wheat varieties in many parts of the world. The pest has extended its distribution throughout the wheat fields of Iran and in particular the East Azarbaijan province. Five modern Iranian wheat varieties, namely Alamoot, Alvand, Zarrin, Sabalan and Sardari, which are the most extensively cultivated in the province, were used in laboratory screening tests for assessment of their antibiosis resistance to the aphid at the stem elongation growth stage. This work was carried out under greenhouse conditions of 24.2±4.5 0C temperature, 55.7±4.6% R.H. and 16:8 (L: D) light regime. The probable antibiosis was assessed by studying the nymphal survival rate; mean developmental time and adult fecundity (total no. of progeny/ female produced within the first 10 and 15 days of reproductive stage) calculating the relevant intrinsic rate of natural population increase (rm value). The ANOVA of the data indicated that regarding duration of nymphal development time, adult fecundity and also rm values, there were significant differences (p<0.01) between the varieties. Based on this, the highest (7.70±0.47) and lowest (5.75±0.44) mean nymphal development time was calculated on Alvand and Sabalan respectively. The greatest (59.35±2.60 & 88.15±4.81) and the least (38.30±2.20 & 58.60±3.42) numbers of progeny produced per female within the first 10 and 15 days of larviposition period was observed on Sabalan and Sardari respectively. Moreover, the highest rm value (0.4120± 0.0074 & 0.4140± 0.0073) obtained for individuals reared on Sabalan, with the lowest (0.2620 ±0.0034& 0.2670±0.0025) being on Alvand. The present study indicated that at the stem elongation stage, Sabalan appeared to be more susceptible to the aphid whilst Alvand was more resistant and Sardari, Alamoot and Zarrin were regarded as intermediate among the others
Resistance, wheat, English grain aphid