GENETIC-ANALYSIS OF AN UNSTABLE, PURPLE-RED HULL RICE MUTATION DERIVED FROM TISSUE-CULTURE

An unstable, dominant mutation for purple-red pigmentation in rice (Or yza saliva L.) has been identified in seed hulls of the tissue culture -regenerated somaclone SC86-20973. Genetic analyses suggested that the purple-red hull character is conditioned by a single dominant nuclear gene. The purple-red hull is dominant over the wild-type green hull i n the F-1, but a reversal of the purple-red hull phenotype in the F-2 reciprocal crosses was observed. Distorted segregation ratios were det ected among 81 F-3 families that were derived from purple-red hulled F -2 plants. All green hulled F-2 and F-3 individuals bred true. A stabl e, dominant purple-apiculus mutation was also observed in the original somaclone, and it was strongly linked to the purple-red hull trait. I t is postulated that the purple-red hull mutation arose as a dominant character that is stable when selfed in the homozygous condition, but which undergoes unidirectional meiotic gene conversion as a heterozygo te.