Registration of Six Wheat-Rye Addition Lines Resistant to the Russian Wheat Aphid

Six wheat-rye (Triticum aestivum L.-Secale cereale L.) addition line genetic stocks-CO03752 (Reg. No. GS-164, PI 659317); CO03754 (Reg. No. GS-165, PI 659318); CO03758 (Reg. No. GS-166, PI 659319); CO03761 (Reg. No. GS-167, PI 659320); CO03764 (Reg. No. GS-168, PI 659321); and CO03765 (Reg. No. GS-169, PI 659322)-having resistance to biotypes 1 and 2 of Russian wheat aphid [RWA; Diuraphis noxia (Kurdjumov)] were developed by Colorado State University in collaboration with Laurentian University (Canada). The PI 386148 triticale (× Triticosecale Wittmack) from Russia is among the most resistant lines to the RWA biotypes 1 and 2. This triticale line was used as the male parent in crosses with the hard red winter wheat (Triticum aestivum L.) cultivar ‘Lamar’ (PI 559719). The lines were derived following five backcross generations using standard greenhouse seedling screening for RWA biotype 1 resistance and three subsequent selfing generations with seedling screening for RWA biotype 2 resistance. Seed of the lines was increased for agronomic and other evaluations. Four lines (CO03752, CO03758, CO03761, and CO03765) are cytologically stable and carry a pair of rye (Secale strictum C. Presl) chromosomes as disomic additions of 1R. One line (CO03764) has 42 wheat chromosomes and 2 heteromorphic rye chromosomes, and one line (CO03754) is unstable and shows a moderate level of mixoploidy with monosomic additions of 1R. Under nonirrigated production conditions, the grain yield and grain volume weight of three of the lines were similar to those of some adapted released wheat varieties.