Genetic analysis of a null-allele for lipoxygenase-3 in rice seeds

Lipoxygenase (LOX) catalyzes peroxidation of lipids in rice grains and is related to the formation of volatile compounds. We report on the mode of inheritance of LOX-3 in the rice variety Daw Dam. This variety lacks the LOX-3 (Suzuki et al., 1993), which is a major isozyme in rice seeds. The inheritance of LOX-3 in rice seeds was determined by crossing Daw Dam with rice cultivars having normal LOX-3 activity. The distribution of F-2 phenotypes for the presence and absence of LOX-3 from selfed F-1 plants fitted the ratio 3:1. Segregation ratio of the B1F1 generation gave a good fit to 1 presence of LOX-3:1 absence. These data support the hypothesis that the lack of LOX-3 is recessive to the presence of LOX-3, and we conclude that the absence of LOX-3 is inherited as a single recessive trait. We discuss the possible use of the LOX-3 less mutation in relation to volatile compounds production in rice grains.