Resistance of Wheat lines to Greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae)
Keywords:
Biological characteristics, green aphid, plants resistance, wheat lines.Abstract
 The greenbug Schizaphis graminum (Rondani) is one of the most important cereal pests in the world. Therefore, we conducted two sets of experiments for evaluating of resistance of wheat lines against this aphid. An initial screening test assessed resistance in forty wheat lines to this aphid in laboratory conditions, and then biological characteristics of this pest were evaluated on eight of these. Test aphids were reared on Hirmand wheat at 25 ± 1OC, 60 ± 5 % R.H. and a photoperiod of 14: 10 h (L: D). The developmental time of immature stage ranged from 6.0 to 7.0 day. Total offspring per female ranged from 33.9 to 60.4 nymphs on N88-19 and N88-8 lines, respectively. Offspring produced per female per reproduction day was the highest on N88-11 (3.3 nymphs) and lowest on N87-8 and N87-9 (2.8 nymphs). The intrinsic rate of natural increase (rm) varied from 0.251 on N88-19 to 0.321 on N88-11. The R0 values ranged from 16.3 on N88-19 to 52.4 on N88-8. The other life table parameters such as λ (finite rate of increase), T (mean generation time) and DT (doubling time) were also calculated. The results of this study indicated that N88-19, N87-11, N87-8 and N87-9 wheat lines are partially resistant against this pest and could be used in integrated pest management (IPM) programs.
