Development and Characterization of Six Wheat – Rye Addition Lines Resistant to the Russian Wheat Aphid (Diuraphis noxia, Mordvilko).

Six wheat – rye addition lines genetic stocks (PI 659317, PI 679318, PI 659319, PI 659320, PI 659321, and PI 659322) having resistance to the biotypes 1 and biotype 2 of Russian Wheat Aphid (RWA) were developed by Colorado State university in collaboration with Laurentian University (Canada). The PI386148 triticale from Russia is among the highest resistant line to the RWA (types 1 and 2). This triticale line was used as the male parent in crosses with Lamar wheat. The F1 plants were backcrossed to Lamar wheat three times. The progenies were tested for RWA reaction for at least eight generations. These five lines from these selections were identified for their resistance to the RWA and their seeds were increased for agronomic and other characterizations. Four lines (CO03752, CO03758, CO03761, and CO03765) were cytologically stable and carried a pair of rye (Secale strictum C. Presl) chromosome as disomic addition lines of 1R. CO03784 line had 42 wheat chromosomes and two heteromorphic rye chromosomes. One line (CO03754) was unstable and showed a moderate level of mixoploidy with monosomic additions of 1R. One rye chromosomes, 1R from the donor species contains genes for RWA resistance. Grain yield and test weight of three of the lines were similar to some adapted released wheat varieties under stress conditions.