A translocation between a common wheat (Triticum aestivum L.) chromosome and chromosome 6 of Elytrigia pontica (Podp.) Holub conferred resistance to feeding by Eriophyes (= Aceria) tulipae Keifer, the mite vector of wheat streak mosaic virus and the wheat spot mosaic agent. Resistance was dominant, but differential transmission occurred between the pollen and the egg. Transmission of resistance through the pollen was low, about 3% in 'Cadet', 'Rescue', and 'Winalta', but significantly higher in 'Norstar' (9.1%). Significant differences also were detected in transmission through the egg. 'Cadet' had the highest transmission (50.9%) and 'Rescue' the lowest (40.5%). However, there were no significant differences among varieties in the frequencies of resistance (50.3–54.5%) in the F2. Less than 10% of the F2 plants were homozygous resistant. Selfed progeny from monosomic or disomic F1 plants from crosses between the homozygous translocation and group-6 monosomics all segregated for susceptibility. Meiotic studies of 25 susceptible F2 plants from these F1 monosomics showed that 21 were either monosomic or disomic and only 4 were nullisomic, indicating that the translocation did not involve any of the group-6 homoeologues. The translocation is considered to be a noncompensating translocation involving a whole arm of chromosome 6 of E. pontica.Key words: wheat, mite (wheat curl), translocation, Triticum.
Brazilian Origin and Inheritance of a Heterozygous Reciprocal Chromosome Translocation in Wheat (Triticum aestivum L.)
