Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Poster: Wheat, Barley, Rye, Oat, and related
            

THE EFFECT OF CYTOPLASM ON THE EXTENT OF RECOMBINATION ON THE 1D AND 5D CHROMOSOMES OF Triticum tauschii

¹ Dept. of Agronomy and Horticulture, 371 Plant Science, University of Nebraska-Lincoln, Lincoln, NE, 68583-0915

² Dept. of Agronomy, G302 Agronomy Hall, Iowa State University-Ames, Ames, IA, 50011-1010

To study the effect of cytoplasm on recombination two sets of backcross populations (`BC1691' and `BC1704') of T. tauschii (the D-genome donor of bread wheat) differing only in the source of cytoplasm were generated. High-density linkage maps were constructed and compared for the set of common markers, 27 for 1D and 12 for 5D chromosomes. The marker order was the same between the physical map of wheat and the genetic linkage map of T. tauschii. The localized effect of cytoplasm on the extent of recombination was observed. The difference in recombination ranged from 2 to 13 fold for a few markers on chromosome 1D and up to 3.3 fold on chromosome 5D. For chromosome 1D there was a general trend of less recombination in the `BC1704' compared to the `BC1691'. The short arm length for the `BC1691' cross was 125.2 cM compared to the 72.5 cM for the `BC1704'. Therefore, the length of the short arm for the 'BC1704' was 58% of that for the `BC1691'. The long arm for the `BC1691' was 130.1 cM compared to the 117.5 cM for the `BC1704'. The values clearly indicate that the short arm contributed more to the difference in recombination between the two crosses. Recombination occurred preferentially in the gene-rich regions. The extent of recombination, however, was dramatically different among various gene-rich regions. Gene-containing regions around the centromere were devoid of recombination. The most recent mapping data will be presented.