Genetic, agronomic and quality comparisons of two 1AL.1RS-Wheat-rye chromosomal translocations

The 1AL.1RS wheat-rye chromosomal translocation originally found in 'Amigo' wheat possesses resistance genes for stem rust, powdery mildew and greenbu g biotypes B and C, but also has a negative effect on wheat processing qual ity. Recently, a second 1AL.1RS translocation carrying Gb6, a gene conferri ng resistance to greenbug biotypes B, C, E, G and I, was identified in the wheat germplasm line 'GRS1201'. Protein analytical methods, and the DNA pol ymerase chain reaction were used to identify markers capable of differentia ting the IRS chromosome arms derived from 'Amigo' and 'GRS1201'. The secali n proteins encoded by genes on 1RS chromosome arms differed in 'Amigo and ' GRS1201'. A 70 kDa secalin was found in the 'Amigo' 1AL.1RS, but did not oc cur in the 'GRS1201' 1AL.1RS. Polymorphisms detected by PCR primers derived from a family of moderately repetitive rye DNA sequences also differentiat ed the two translocations. When 'GRS1201' was mated with a non-1RS wheat, n o recombinants between 1RS markers were observed. In crosses between 1RS an d non-1RS parents, both DNA markers and secalins would be useful as selecta ble markers for 1RS-derived greenbug resistance. Recombination between 1RS markers did occur when 1RS from 'Amigo' and 1RS from 'GRS1201' were combine d, but in such intermatings, the molecular markers described herein could s till be used to develop a population enriched in lines carrying Gb6. No dif ferences in grain yield or grain and flour quality characteristics were obs erved when lines carrying 1RS from 'Amigo' were compared with lines with 1R S from 'GRS1201'. Hence, differences in secalin composition did not result in differential quality effects. When compared with sister lines with 1AL.1 AS derived from the wheat cultivar 'Redland', lines with 'GRS1201' had equa l grain yield, but produced flours with significantly shorter mix times, we aker doughs, and lower sodium dodecyl sulphate sedimentation volumes.