Identification of barley genome segments introgressed into wheat using PCRmarkers

Barley has several important traits that might be used in the genetic impro vement of wheat. For this report, we have produced wheat-barley recombinant s involving barley chromosomes 4 (4H) and 7 (5H). Wheat-barley disomic addi tion lines were crossed with 'Chinese Spring' wheat carrying the ph1b mutat ion to promote homoeologous pairing. Selection was performed using polymera se chain reaction (PCR) markers to identify lines with the barley chromosom e in the ph1b background. These lines were self pollinated, and recombinant s were identified using sequence-tagged-site (STS) primer sets that allowed differentiation between barley and wheat chromosomes. Several recombinant lines were isolated that involved different STS-PCR markers. Recombination was confirmed by allowing the lines to self pollinate and rescreening the p rogeny via STS-PCR. Progeny testing confirmed 9 recombinants involving barl ey chromosome 4 (4H) and 11 recombinants involving barley chromosome 7 (5H) . Some recombinants were observed cytologically to eliminate the possibilit y of broken chromosomes. Since transmission of the recombinant chromosomes was lower than expected and since seed set was reduced in recombinant lines , the utility of producing recombinants with this method is uncertain.