Interspecific hybridization of diploids and octoploids in strawberry

Interspecific crosses were performed among accessions of the wild strawberry species F. vesca and F. nilgerrensis and the cultivated strawberry, F. × ananassa, following reciprocal crossing. Crosses between both F. vesca species ‘Hawaii-30’ and ‘UC-01’ were successful regardless of the presence of reciprocal crossing, while crosses with ‘Whiteberry’ of the F. nilgerrensis species were not successful. In particular, intraspecific hybridization of ‘Hawaii-30’ and ‘UC-01’ in the F. vesca species produced a tetraploid plant. Although octoploid ‘Akihime’ did not cross with different species, it performed well with ‘Hawaii-30’ only through the parent seed. Progenies of interspecific hybridization between species of different ploidy, namely ‘Hawaii-30’ and ‘Akihime’, produced 12 pentaploid plants with an intermediate phenotype between the crossing parents and characterized by sterility. In addition, despite its poor hybridization, a cross-combination between ‘Akihime’ and ‘Whiteberry’ produced one pentaploid plant, which did not bloom.

► We investigated characteristics of diploid and octoploid species in strawberry. ► We performed interspecific crosses among species different polyploidy. ► We examined cross-compatibility following reciprocal crossing. ► Interspecific hybridization with different polyploidy does not perform cross-pollination well and showed many differences depending on cross-combinations. ► Pentaploid and tetraploid plants were found by interspecific and intraspecific crosses.