A group of 61 synthetic hexaploid wheat derived from crosses between Triticum dicoccum (Schrank) and Aegilops tauschii ((Cross.) Schmal.) were together with their T. dicoccum parents screened for resistance to greenbugs, Schizaphis graminum (Rondani) at seedling stage. The screenings revealed a group of 12 synthetics showing resistant to moderate resistant responses. The T. dicoccum parents were all highly susceptible, leading to the conclusion that any resistance towards greenbugs in the synthetics must come from their Ae. tauschii parents. The 12 resistant synthetics, derived from nine different Ae. tauschii parents, were subjected to further studies of their resistance mechanisms. The antixenosis testing was performed on individual leaves enclosed in a petri dish, to where five adult aphids per leaf was added. 24 h later the number of aphid on each leaf was determined. For testing for tolerance plants were subjected to a continuously heavy aphid infestation by adding aphids to the plants daily, where after plant height, damage rating, and dry weight was recorded. Antibiosis was determined by the nymph count technique with individual aphids enclosed in a clip-cage. The results from the three resistance mechanism tests were combined in a plant resistance index.
Species 1: Homoptera Ahididae Schizaphis graminum (greenbug)
Keywords: plant resistance, synthethic hexaploid wheat
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA