S. MOJAHED, J. RAZMJOU and A. GOLIZADEH
Department of Plant Protection, Faculty of Agriculture, University of Mohaghegh Ardabili, Ardabil, Iran
MOJAHED, S., J. RAZMJOU and A. GOLIZADEH, 2013. Resistance and susceptibility of some wheat cultivars and lines to greenbug, Schizaphis graminum Rondani (Homoptera: Aphididae). Bulg. J. Agric. Sci., 19: 714-720
The greenbug, Schizaphis graminum Rondani (Homoptera: Aphididae) is one of the most important pests of cereal particularly wheat, and transmits plant disease viruses such as barley yellow dwarf virus (BYDV). In this study, resistance and susceptibility of 16 cultivars and 20 wheat lines to S. graminum was evaluated under laboratory conditions. First, the screening test was carried out at 25 ± 1˚C, 60 ± 5% RH and a photoperiod of 14:10 (L;D) in a growth chamber using a completely randomized design and then the biological characteristics of this pest were evaluated on three cultivars (namely Kouhdasht, Bezostaya, and Hirmand) and four lines (namely ERWYT 87-7, ERWYT 87-8, ERWYT87-15, and ERWYT87-16), that were selected in the screening test. The antibiosis test was based on the life table parameters. Results proved that the developmental time of immature stage ranged from 7 days on ERWYT 87-16 to 6.4 days on Kouhdasht. The lowest aphid fertility rate was obtained on ERWYT87-16 line (47.6 nymphs) comparing to the fertility yielded on Kouhdasht cultivar (66 nymphs) that was significantly higher. The highest and lowest rm values were observed on Hirmand (0.369 nymphs/female/day) and ERWYT87-16 (0.312 nymphs/female/day), respectively. In addition, there were significant differences among the wheat cultivars and lines for all other parameters. The mean generation time (T), net reproductive rate (R0), doubling time (DT) and the finite rate of increase (λ) on wheat cultivars and lines were 9.7-11.5 days, 28.2-61.6 nymphs/female, 1.9-2.1 days and 1.373-1.437 nymphs/female/day, respectively. As a result, our findings showed that the ERWYT 87-16 and ERWYT 87-7 lines were partially resistant against S. graminum, whereas Kouhdasht and Hirmand were relatively susceptible.