Abstract
Allelism tests among 15 independently established dwarf lines revealed that five loci are involved in dwarfism in common buckwheat. They are designated dwA, dwB, dwC, dwD and dwE. The frequencies of dwarf mutants at four loci, dwA, dwB, dwC and dwD were investigated in three Japanese populations, Iwate, Togakushi, Higashi-Iyayama, by using four representative homozygous lines as the testers. The frequencies varied slightly among the populations, but on the average they were 0.235%, 0.067%, 0.294% and 0.196% for the dwA, dwB, dwC and dwD loci, respectively. These low allele frequencies imply that the recurrent mutation is balanced by selection against the dwarf alleles. This conclusion was confirmed by supplemental data on the frequency of dwarf mutants per gamete and a field survey of dwarf homozygotes in randomly mating populations in farmer′s field. Approximately 0.50% of the gametes contain a dwarf allele, whereas the incidence of dwarfism in the randomly mating populations was only 4.25 ×10-6. The latter estimate was based on a study of more than 3 million plants.
