Flowering performance and yield of established and recent strawberry cultivars (Fragaria × ananassa) as affected by raising temperature and photoperiod

ABSTRACT

Plants of six strawberry cultivars were raised under controlled conditions and tested for flowering and yield potential. Short days (SD) at intermediate temperatures for 4 weeks in August induced profuse flowering in subsequent long days (LD) in all cultivars except the late-flowering ‘Malwina’. LD conditions induced flowering only in ‘Nobel’, which has an everbearing parent. ‘Nobel’ and ‘Saga’ exhibited broad temperature adaptation for SD floral induction, which was generally reduced or suppressed at 9 and 27°C. After autumn planting, all cultivars flowered most abundantly in plants raised in SD and intermediate temperatures. Flowering was earliest in ‘Nobel’ and ‘Rumba’. Plants that did not reach floral commitment after 4 weeks in SD continued and completed induction under subsequent natural SD conditions after planting in the field, demonstrating the capability of fractional induction. Berry yield varied in parallel with flowering in the field and was always higher in plants raised under SD conditions. The traditional cultivars ‘Florence’ and ‘Sonata’ out-yielded the more recent cultivars. Some cultivars lost more than two thirds of their initiated flowers during the winter with obvious consequences for their yields. With proper raising management, acceptable yields were obtained after autumn planting even in a cool Nordic climate.

KEYWORDS:

• Flowering
• fractional induction
• photoperiod
• strawberry cultivars
• temperature
• yield

Acknowledgements

The authors acknowledge Unni M. Roos and Hans G. Espelien for excellent technical assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Norwegian Agricultural Agreement Research Fund/Foundation for Research Levy on Agricultural Products [grant number 225154/E40]; and the European Union’s Horizon 2020 research and innovation program [grant number 679303].