Effect of Different Post-Flowering Photoperiods on Main Agronomic Traits of Strawberry (Fragaria × ananassa Duch. cv. Akihime)

Reproductive growth is one of the most important stages in the life history of plants and is regulated by photoperiod. However, the effect of different photoperiods after flowering on the reproductive growth stages of different plants and their roles is still unclear. For this reason, this study took the short-day plant strawberry (Fragaria × ananassa Duch. cv. Akihime) as the research object, performed different photoperiod treatments (ND: natural daylight; SD: short daylight; LD: long daylight) after flowering, and studied the effects of photoperiod on fruit growth period, fruit quality, flower opening, and plant height in different inflorescence of fruits. The results showed that different photoperiods had significantly different effects on the growth and development of strawberries after flowering, and LD and SD had opposite effects: (1) Under the condition of SD, the fruit matured after 17 days of treatment, while the LD and ND advanced this by 6 and 5 days. LD could significantly delay the development of the first inflorescence of fruits, resulting in longer ripening period and fruit appearance, and the quality traits were better. (2) The number of flowers in the secondary inflorescence and the development process was effectively accelerated by LD, and the total number of flowers under the long-day treatment was significantly more than that under the short-day treatment and the natural condition from 12 to 25 days after the end of the flowering period. Under the condition of LD, the fruits matured after 53 days of treatment, which was 5 days earlier than the other two treatments, and the period from flowering to maturity was shortened. (3) The effect of different photoperiods on the final plant height of strawberries after flowering had no significant difference (p < 0.05). In conclusion, this study found that photoperiod could effectively regulate the reproductive growth stage of strawberry after flowering, which enriched the experimental material and theoretical basis for studying the photoperiod as a mechanism for regulating plant growth and development, providing technical guidance for artificial regulation of strawberry growth period and fruit quality.