Genetics of Floral Longevity in Petunia

Abstract

Petunia hybrida Vilm. is one of the major bedding plants grown worldwide, and, like most bedding plants, is grown primarily for its seasonal floral display. While increased floral and reflowering capacity have been the focus of breeding programs for many ornamental species, floral longevity has received little direct attention. Increased floral longevity would enhance the value of any crop grown for floral effect. In this study, four parental genotypes (two with short flower life, two with long flower life) were crossed in a partial diallel mating design to create six F 1 families. The F 1 individuals were then selfed and backcrossed to the appropriate parents to create F 2 and backcross families. Data from parental and F 1 genotypes were analyzed to determine general and specific combining ability for floral longevity in petunia. Results indicated the presence of significant additive gene effects and nonsignificant nonadditive gene effects for floral longevity in this germplasm. However, aberrant F 2 and backcross family means were observed in all families. For each family, F 2 and backcross means were lower than expected given normal Mendelian segregation. Further experiments will be necessary to elucidate the causes for the deviate F 2 and backcross family means before specific recommendations for selecting for increased floral longevity in petunia can be made.