Field population development of bird cherry-oat aphid and greenbug (Hemiptera: Aphididae) on wheat-alien substitution and translocation lines

Abstract

The aphids Rhopalosiphum padi L. and Schizaphis graminum (Rondani) are destructive pests of wheat (Triticum aestivum L.). In field trials in north-west Mexico, we examined the development of R. padi and S. graminum populations on six wheat genotypes that had previously been assessed for aphid resistance under controlled conditions. Five of these wheat genotypes carried different alien translocations in the genetic background of the spring wheat cultivar Pavon F76, which was used as the control. The trials were established in a randomized complete block design and repeated in three successive sowings. Aphids were sampled weekly from tillering stage until collapse of the aphid populations in the control. Number of aphid-days (i.e. the area under the curve of aphids per tiller) was calculated to compare population sizes. Genotypes 1AL.1RSe and (1D)1Rpr significantly reduced R. padi populations across all sowing dates, by 32.8 and 24.1 %, respectively, compared with the control. Interaction between the wheat genotypes and sowing had a significant effect on the aphid-days of S. graminum. Genotype 7A.7S-L5 with Aegilops speltoides Tausch chromatin significantly reduced the S. graminum population by between 48.5 and 74.8 % in the three sowings compared with the control. These three wheat genotypes were also previously characterized as resistant in laboratory trials and can be considered promising resistance sources to R. padi and S. graminum in wheat breeding programs.