Minimization of alien chromatin volume in the introgressive common wheat lines

Abstract

Among developed by us introgressive hexaploid common wheat lines, the ones resistant to powdery mildew owing to involving Aegilops speltoides and Ae. sharonensis in their pedigrees were found. Only the D chromosomes were involved in genome rearrangement. Four means of minimizing alien chromatin, namely, irradiation o f hybrids F1 from crossing these lines with promising common wheat varieties with gamma-rays, crossing the same hybrids with the Chinese Spring ph1 and ph2 mutants, action of Ae. speltoides genotype, and action of gametocidal 4Sl chromosome were used. There was 80% loss of hybrids after irradiation. Four out of 21 F2 populations contained several resistant plants. No success was achieved by using ph-mutants, perhaps, due to winter nature of introgressive lines. Out of five F2, populations related to Ae.speltoides, the segregation 3 susceptible : 1 resistant was found in one event. The resistance gene of Ae.speltoides is thought to be novel for common wheat. One line out of 16 resistant ones originated from Ae. sharonensis was found to contain a single dominant gene for resistance in small segment of alien chromatin. The resistance genes from both Aegilops species are believed to be situated in the 3rd homoeologous group of Aegilops. Four microsatellite primers on chromosome 3D were successfully used for search molecular evidence of alien chromatin presence in this chromosome in resistant lines.