CHROMOSOME AND CHROMOSOMAL ARM LOCATIONS OF GENES FOR RESISTANCE TO SEPTORIA GLUME BLOTCH IN WHEAT CULTIVAR COTIPORA

Septoria glume blotch, caused by Stagonospora nodorum, is an important disease of wheat (Triticum aestivum). Separate genetic mechanisms wer e found to control flag leaf and spike resistance. Genes for resistanc e to S. nodorum were located on different chromosomes in the few wheat cultivars studied. These studies only partially agree on the chromoso me locations of gene in wheat for resistance to S. nodorum, and chromo somal arm locations of such genes are not known. The objectives of thi s study were to determine the chromosome and chromosomal arm locations of genes that significantly influence resistance to S. nodorum in whe at cultivar Cotipora. Monosomic analysis showed that flag leaf resista nce was controlled by genes on chromosomes 3A, 4A, and 3B whereas the spike resistance was controlled by genes on chromosomes 3A, 4A, 7A, an d 3B (P = 0.01). Additionally, genes on chromosomes 6B and 5A influenc ed the susceptibility of the flag leaf and spike reactions, respective ly (P = 0.01). Telocentric analysis showed that genes on both arms of chromosome 3A, and the long arms of chromosomes 4A and 3B were involve d in the flag leaf resistance whereas genes on both arms of chromosome 4A, the short arm of chromosome 3A, and the long arm of chromosome 3B conferred spike resistance.