An Unstable Mutation Affecting Tomato Reproductive Development

Somatic sectors possessing mutations affecting flower and fruit development were found at a high frequency in an F4 tomato plot. Over the past 4 years, this population has manifested a range of variant phenotypes, including conversion of calyx to leaflets; flecking, striping of sectoring of fruit; and development of “prolific callus” (PC) fruit, characterized by the green fruit bursting open, with new flowering shoots developing from the internal tissue. The variant phenotypes were not stably inherited. The majority of plants having sectors with abnormal flowers, abnormal fruit, or PC fruit developed phenotypically distinct somatic sectors. The aberrant phenotype ratios, the very high frequency of somatic reversions toward normal development, and the range of traits affecting tomato reproductive development indicate this could involve a transposable element interacting with control genes involved in tomato reproduction, with the phenotype partly dependent on the timing of the transposition event.