Greenhug (Homoptera: Aphididae) Resistance in Triticale

The advent of the new biotype E greenbug, Schizaphis graminum (Rondani) has demonstrated the need to isolate new sources of resistance because this biotype damages previously resistant wheat, Triticum aestivum L., sources. Thus, 264 new Introductions of triticale (x Triticosecale Wittmack) lines were evaluated In the greenhouse for resistance to the new biotype. Seven of these lines were highly resistant, and two were in the intermediate range. Selected entries of these lines were subjected to more detailed studies to determine the components of resistance, i.e., antibiosis (fecundity): nonpreference (using free-choice tests), and tolerance (plant damage). Triticale lines which warrant further research as possible new genetic sources of greenbug resistance, not only in triticale, but also in wheat, include PI 429052, PI 429193, PI 429235, PI 429245, PI 429247, and PI 429251.