Ethylene-insensitive related phenotypes exist naturally in a genetically variable population of Dianthus barbatus

Within the genetically variable population of Dianthus barbatus "Dagan", we identified genetic lines with flowers possessing ethylene insensitivite-re lated phenotypes. The phenotypes are: Caf(+), with a fresh-looking corolla attached to a mature ovary; Inr(-), with flowers whose petals do not inroll during flower senescence; and Rfi(+), whose flower petals inroll, but reco ver from inrolling. The frequencies of Caf(+), Inr(-) and Rfi(+) were 33%, 25% and 75% in the population inspected, respectively. These relatively hig h frequencies were probably due to continuous selection over the years for flowers with open and long-lasting corollas. By examining the distribution of the genetic lines which express two of these phenotypes, we determined t hat Caf(+), Inr(-) and Rfi(+) are independent traits. However, these traits might be associated with male sterility. Exposure of a random sample of th e population to exogenous ethylene, followed by examination of the resultin g inrolling and wilting, revealed five different ethylene response groups. In one group ethylene enhanced both inrolling and wilting, and most genetic lines within this group exhibited a Caf(-) phenotype. In two other groups ethylene enhanced either the inrolling or the wilting, and both of the Caf( +) and Caf(-) phenotypes were included. Two other groups were completely no n-responsive to ethylene, but in one of them the flower life span was twice as long as in the other, and all the genetic lines exhibited the Caf(+) ph enotype. We concluded that the Caf(+) phenotype is most-likely related to e thylene insensitivity and that the inrolling and wilting are controlled by ethylene, probably via different pathways.