Transfer of the petaloid-type CMS in carrot by donor-recipient protoplast fusion.

Abstract

The CMS trait of petaloid-type flowers in carrot was tried to transfer to fertile varieties by donor-recipient protoplast fusion. X-irradiated protoplasts of the carrot CMS line, 31A, and iodoacetamide-treated protoplasts of 5 different fertile varleties were used as a cyioplasmic donor and recipients, respectively. Fifty-eight plants were regenerated from the fusion experiments and no plant with petaloid flowers was observed. A11 the regenerated plants were fertile or male sterile with brown anthers. To produce cybrlds with petaloid-type flowers, Z1, which is a regenerated plant obtained from protoplast fusion between 31A and K5, was used as a cytoplasmic recipient and fused with X-irradiated protoplasts of 31A. From this donor-recipient protoplast fusion, 41 fusion products were regenerated and bore flowers. Among them, 39 plants were CMS with petaloid stamens and 2 plants were the same male sterile with brown anthers as Z1. Chromosomal and mitochondrial DNA analyses of the fusion products revealed that all of the plants investigated had nuclei derived from Z1 and rearranged mtDNAs. After crossing with fertile varieties including K5, the petaloid male sterility of the fusion products was maternally inherited in the F1 and F1B1 generations. Other agronomic traits of the progenies were similar to those of the parental fertile line. The results indicate that the petaloid CMS trait can be transferred effectively to another carrot line by using two-step donor-recipient protoplast fusion.