Resistance to the Bird Cherry-Oat Aphid, Rhopalosiphum padi L. (Homoptera: Aphididae), in Perennial Gramineae and Wheat × Perennial Gramineae Hybrids

The potential for resistance to Rhopalosiphum padi (L.) was evaluated in seedlings of Agropyron elongatum (Host.) Beauv., Agropyron intermedium (Host.) Beauv., Agropyron repens L. Beauv., Elymus angustus Trin., and hybrids obtained from crosses between these perennial Gramineae and cultivated wheat, Triticum aestivum L. Binary choice tests designed to detect antixenosis showed that A. repens and the hybrid wheat × A. repens were less attractive than the two parental wheat varieties used to produce the hybrid ( P < 0.05). Parameters of aphid performance, including reproductive rate, duration of prereproductive period, adult fresh weight, and aphid biomass, also allowed the detection of various levels of antibiosis in the four perennial grasses and hybrids tested. Results showed that natural resistance found in Agropyron and Elymus spp. can be successfully transmitted to hybrids produced from their crosses with cultivated wheat.