Inheritance of Resistance of PI 372129 Wheat to the Russian Wheat Aphid

Knowledge of the inheritance of resistance to pests in wheat ( Triticum aestivum L.) is important to plant breeders. A study was conducted to determine the inheritance of resistance to the Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), in a wheat line, PI 372129, that was previously identified as a good source of RWA resistance. The susceptible wheat cultivars Carson, Lamar, and TAM 107 were crossed with PI 372129. The parents and progenies from these three crosses were artificially infested with RWA in the greenhouse. There was close association between leaf chlorosis and leaf rolling, two components of the RWA damage rating system. Seedling reactions of the F 1 , F 2 , and backcross generations indicated that a single dominant gene governs RWA resistance in PI 372129. Data describing the mechanism of RWA resistance of PI 372129 indicate that this gene is probably different from Dnl and Dn2 (identified in PI 137739 and PI 262660, respectively). Reciprocal crosses revealed no evidence of cytoplasmic effects.