Varietal Differences and Selection Indicators for Flowering Pattern in Everbearing Strawberry

Abstract

We evaluated varietal differences in everbearing strawberry (Fragaria × ananassa Duch.) and selection indicators of flowering pattern by investigating the numbers of inflorescences and individual flowers together with their flowering dates from spring to autumn. Highly significant (P < 0.001) differences among varieties in these traits indicate a genetic basis for the strength of everbearing. The results suggest that parentage is involved in the strength of everbearing. Varieties in the ‘Oishi-shikinari’ lineage flowered earlier in summer, with fewer leaves emerging between spring and summer inflorescences, and had more inflorescences than the ‘Kaho’ and F. virginiana Duch. ssp. glauca (Wats.) Staudt lineages. The earliness of flowering of June-bearing parents in spring also seemed to influence their offspring’s first flowering date of summer inflorescences. Thus, the use of early-flowering June-bearers may facilitate the breeding of strong everbearing varieties. These lines of evidence suggest that the choice of mating parents is crucial for breeding focused on the ‘strength’ of everbearing. Significant correlations (r = −0.65 to −0.78) were found between two phenological traits (the first flowering date of summer inflorescences and the number of leaves emerging between spring and summer inflorescences) and traits representing the strength of everbearing, including the numbers of inflorescences and individual flowers. These results suggest the appropriateness of those phenological traits as selection indicators for the flowering pattern of everbearing.