An evaluation of intergeneric hybridization of Fragaria spp. x Potentilla spp. as a means of haploid production

Abstract

Unidirectional intergeneric crosses using octoploid and hexaploid Fragaria species as a female parent and diploid and tetraploid Potentilla species as a male parent were performed, producing in toto 1345 fruits with an estimated 46089 seeds. The germinating seeds obtained by using P. anserina mostly perished at the cotyledon stage, a few developing into matroclinous octoploid seedlings. The seeds obtained by using P. fruiticosa produced two types of seedlings: matroclinous octoploids and genuine intergeneric hybrids. It is considered that the matroclinous octoploids resulted from contamination during the emasculation process. A great majority of the hybrid seedlings were slow in growth and development and perished before reaching the flowering stage. No haploids have been recovered. Possible reasons for absence of haploid genotypes in the progenies of these intergeneric crosses are considered. Among the seedlings of F. x ananassa cv. Tioga x P. fruiticosa, a seedling of an unusual phenotype was noticed, which upon chromosome determination, proved to be 2n=9x=63. This genotype displayed complete male and female sterility. The implication of the sterility of this seedling for bridging of the two genera is discussed.