Characteristics and inheritance of radiation-induced mutations in barley II. Two short-awned mutations

Abstract

Two mutations were obtained in a two-rowed, spring-type barley variety, Asahi No. 5. KM 114 was obtained in the X₂ population of X-irradiated dormant seeds (15 Kr) and KM 218 was found in X₂ of gamma-irradiated seeds (15 Kr). KM 114 had very short awns, short plant height, almost normal spike size, and narrow and thinner seeds with pointed tip. The mutant gene is Mendelian recessive. KM 218 plants were normal or slightly taller, had somewhat larger spike, with somewhat longer rachis internodes, medium-long awn, and slightly longer, narrower and thinner kernel than those of the parental variety. At maturity, grains are exposed in many seeds (semi-naked kernels). This mutant also has a conspicuous diagnostic trait; the abnormal development of rachilla into extra florets, some of which set seeds. This mutant gene is also Mendelian recessive. Genes for these two mutants are not allelic and are inherited independently as indicated in F₂ and F₃ analyses. Genes of these two mutations will serve as good marker genes in genetic and linkage studies in barley, because their character expression is consistent and the recessive homozygotes are viable and fertile.