Molecular genetic analyses of wheat-rye chromosomal translocations and substitutions.

摘要

The 1AL/1RS translocation found in 'Amigo' wheat possesses genes for stem rust, powdery mildew, and greenbug resistance. Recently, new germplasm lines GRS 1201 and GRS 1205, with resistance to greenbug biotypes B, C, E, G and I, were identified. IRS of the GRS lines was differentiated from 1RS derived from Amigo using protein gel electrophoresis, immunochemical methods, and the polymerase chain reaction. GRS 1201 carries a 1AL/1RS wheat-rye chromosomal translocation, while GRS 1205 was found to possess an entire rye chromosome (1RL/1RS) substituted for wheat chromosome 1A. Among 1RS sources, polymorphic banding patterns specific to each line were observed. Protein (secalin and 1A HMW glutenin) and PCR markers also were used to determine whether recombination occurs between rye chromosomes and wheat homoeologous chromosomes, and 1RS chromosome arms in wheat genetic backgrounds. Recombination between homoeologous chromosomes was not observed in two populations derived from crosses between non-translocation and 1AL/1RS translocations. Two putative recombinants from a cross of a non-translocation stock and the IR(1A) substitution were found. The PCR markers were located about 13.94 cM from the secalin protein markers. A map distance of 37.90 cM was estimated between the secalin markers and the centromere.; A 2RL/2BS wheat-rye translocation, 'Hamlet', derived from crosses between 'Chaupon' rye and hexaploid wheat, has a resistance gene to Hessian fly biotype L. Biotype L is the most virulent biotype presently found in the field. However, 2RL does not have any storage protein or other easily scored markers. This can be a significant problem for plant breeders in identifying resistant lines as screening for insect resistance can be difficult. In this research, we identified PCR markers specific to rye chromosome 2RL, and verified 2RL rye chromosomal segments by genomic in situ hybridization.