Induction and floral differentiation in white strawberry (Fragaria chiloensis subsp. Chiloensis f. chiloensis)

The white strawberry (Fragaria chiloensis) has great potential as an alternative product with excellent organoleptic quality. However, this species bears only one inflorescence per year, so productivity is very low (4-6 t ha1). In red strawberry (Fragaria × ananassa), the morphology, plant architecture model and flower physiology are well known, while in the case of the white strawberry these topics have been little studied and apparently it would have a different behavior. Based on this background, we carried out a phenotypic characterization of Chilean white strawberry (F. chiloensis subsp. chiloensis f. chiloensis) and Chilean wild form (F. chiloensis subsp. chiloensis f. patagonica). To evaluate induction and floral differentiation, we performed a meristematic analysis during the winter rest (June) and early spring (September). Finally, we observed the flowering under greenhouse conditions (November). In June, both accessions had differentiated only the apical meristem of the main shoot. In early September, the Chilean white strawberry maintained its initial condition, whereas the wild form showed more shoots, which were developed from axillary buds. These axillary shoots also were flower differentiated in the terminal meristem. The phenotype in greenhouse was congruent with these observations. The Chilean white strawberry only developed one shoot (crown) per plant with one inflorescence during the season, while wild strawberry developed 10-15 secondary and tertiary shoots per plant, each with its own terminal inflorescence. Results indicated that Chilean white strawberry flower differentiated only the apical meristem in inductive condition. Therefore, likely an apical dominance effect and heavy bud dormancy may limit the formation of the lateral shoots, finally determining a very low production potential, while in the Chilean wild form the apical dominance is lower and the branching capacity is higher.