GENETIC-MARKER SEGREGATIONS IN DOUBLED HAPLOIDS IN SPRING WHEAT CROSSES

In single seed descent lines (SSDs) and anther culture derived doubled haploid lines (DHs) from 6 spring wheat crosses, marker genes (glutenins, isozymes, awns, yellow rust resistance) were analysed. In the SSDs, 7 cases of significantly skewed segregation ratios were found (5 at p < 0.05 or less, 2 at p < 0.10), among the 17 cases investigated. In several crosses, a certain number of DHs were heterozygous or contained ''alien'' alleles, probably due to an increased outcrossing rate. This did not affect segregation ratios, and distortions were as frequent as in the SSDs, but generally less statistically significant (3 at p < 0.05 or less, 4 at p < 0.10). A parallel deviation in DHs and SSDs was found in 2 cases, one case of opposite deviations was found, otherwise only one system deviated for each marker/cross combination. The results indicate that skewed segregation ratios may be significant factors in wheat due to (1) intergenotypic competition and/or gametic selection in derivation of SSDs or (2) in vitro selection in anther cultures.