Most Japanese barley varieties show cleistogamy, but Satsuki Nijyo, one of the Japanese commercial varieties developed by Sapporo Breweries Ltd., is generally recognized to show chasmogamy. No report has been found on the number of genes, or the type of gene effects that control the cleistogamy chasmogamy character in barley. In order to study the inheritance of this character, we surveyed 23 commercial Japanese barley varieties and 54 foreign varieties in 1987/88. Of the Japanese varieties, only one (Satsuki Nijyo) showed chasmogamy, while most foreign varieties showed chasmogamy. We also investigated the average number of relic anthers of matured seeds in 23 Japanese varieties and one foreign variety in 1989/90. Though the average number of relic anthers in matured seeds of Satsuki Nijyo was 0.5, the other varieties showed 1.6 to 3.0. Nine Japanese varieties, including Misato golden, showed 3.0. Therefore, it was reconfirmed that Satsuki Nijyo shows chasmogamy and that Misato golden shows cleistogamy. On the basis of these results, we crossed Satsuki Nijyo (having purple auricles) and Misato golden (having white auricles). The F₁ showed cleistogamy and purple auricle color. When the F₁ was backcrossed to Misatogolden, the progeny segregated as 13 cleistogamous lines with homozygous alleles and 12 lines with heterozygous alleles. This fits a ratio of one homozygote to one heterozygote (X²=0.04, 0.75<P<0.90). The B₁F₂plants from the heterozygous plants segregated as 88 cleistogamous plants and 30 chasmogamous plants, which gives a good fit to a 3:1 ratio (x²=0.01, 0.9<P). Consequently, it was determined that cleistogamy is controlled by a single recessive gene. From the segregation pattern for cleistogamy chasmogamy and auricle color (Table 1), these two allelomorphs were independent to each other (x²=1.21, 0.25<P<0.50).

Table 1. Segregation for cleistogamy-chasmogarny and auricle color in the backcross of Satsuki Nijyo/Misato golden to Misato golden.