Genetic analysis of resistance to barley scald (Rhynchosporium secalis) in a field of the resistant cultivar Brier and its application to breeding
2008
Nakamura Aoki, E.(National Inst. of Crop Science, Tsukuba, Ibaraki (Japan)) | Yamaguchi, O. | Ito, S. | Moriwaki, J. | Baba, T.
The genetic analysis of scald (Rhynchosporium secalis (Oud.) Davis) resistance of barley plants was conducted among progeny lines derived from crosses that include Brier as a donor parent for resistance. Phenotypic and genotypic correlations between the severity of infection and growth characteristics, yield, and pearled-grain quality were calculated for Fsub(2) generations to clarify problems regarding introducing resistance genes of Brier into Japanese varieties. Barley plants in the early tilling stage in a field were infected with scald by distributing infected barley seedlings which had been inoculated in a greenhouse by fungus strain NB1-1-1, classified as a dominant race in the Hokuriku district. Genetic segregations of resistance were investigated using progeny lines evaluated on a scale of zero to five for the severity of infection at 30 days after heading in a field. The resistance to scald seemed to be controlled by three recessive genes which were highly heritable, suggesting that it is relatively straightforward to select plants with high-level resistance in an early hybrid generation. However, heritability for resistance was low in environments unsuitable for scald infection and development. Inoculation tests must be conducted for several years to evaluate the resistance of plants. In the present experiments, a small number of progeny with resistance and marked quality was obtained by a single cross with Brier. Therefore, successive crosses among favorable progeny lines appear promising. It is necessary to choose parents to cross with Brier carefully, because Brier's resistance to scald may be associated with undesirable traits such as late maturity and low pearled-grain whiteness.
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