Carnation (Dianthus caryophyllus L.) dihaploid lines resistant to Fusarium oxysporum f. sp dianthi

Homozygous dihaploid lines (DHLs) from standard carnation (Dianthus caryophyllus L.) clones, resistant to Fusarium oxysporum f. sp. dianthi could be used to accelerate breeding for new resistant varieties. So far, a protocol for the production of haploids from standard carnation clones has not been published. Our preliminary studies have shown that in vitro anther culture resulted in the generation of callus and indirect shoot organogenesis. Isozyme patterns of the regenerated plants demonstrated that these were heterozygous and consequently not originated from the microspores but the somatic anther wall. Standard carnation clones, resistant to F. oxysporum, were also used in in situ induced parthenogenesis through pollination with gamma-irradiated pollen and in vitro embryo rescue. Putative parthenogenic embryos, with abnormal cotyledons or without them, were induced through this protocol. Isozyme patterns and flow cytometry of nuclei proved the recovery of haploid and dihaploid plants, and the early in vitro diploidization of most parthenogenic embryos. Fertile DHLs ('D220', 'D504' and 'D524'), resistant to F. oxysporum, proved to be homozygous for the three genes involved in this resistance after transferring this character to all the progeny of a susceptible clone.