Investigation on resistance of genotypes of rapeseed (Brassica napus L.) to cabbage aphid (Brevicoryne brassicae L.).
2012
Mohiseni, Abdolamir | Torkamani Pirmishani, Abbas
The cabbage aphid, Brevicoryne brassicae (L.), despite all attempts to control its infestatiobn, remains one of the most important pests of horticultural and oil-seed crops. This research was conducted to evaluate resistance of 48 rapeseed (Brassica napus L.) genotypes to cabbage aphid at Borujerd Agriculltural Research Station during 2001-2003. In the first year, out of 48 genotypes, 8 showed a moderately resistance in comparison to others. These 8 genotypes and a susceptible one (VDH8003/98) were re-evaluated under field and laboratory condition in the second year. Under field condition, genotypes were compared based on infested stem length, infestation index (infested stem length Χ percentage of infested plants ), number of pod/main stem, number of seed/pod and yield. Results of field studies showed that VDH 8003/98 and Arc- 2 were highly susceptible and PF7045/91 was the most resistant plant. Study of agronomic parameters showed that the loss of pods/main stem in genotypes of Arc-2, Parada, VDH8003/98 and Pastel, affected by cabbage aphid, were significantly higer than PF7045/91 and Opera. In laboratory, intrinsic rate of natural increase (rm) was measured, indicating that the most and the least rm belonged to VDH 8003/98 and PF7045/91 respectively. Key words: Brassica napus , Brevicoryne brassicae, Resistance , Genotypes.
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