Effect of microclimate and photosynthesis on strawberry reproductive growth in a greenhouse: using cumulative leaf photosynthesis as an index to predict the time of harvest

We evaluate whether cumulative photosynthesis (An,C) could predict the time of harvest in strawberry better than light (IC) or temperature (Ta,C) as forecast indices. We monitored the daily dynamics of flowering, fruit set, and harvest in over 2,700 fruits across the growing season in a greenhouse in Japan. Photosynthesis was calculated using a biochemical model, and An,C calculated by totalling the cumulative rate from flowering to harvest in each fruit. IC and Ta,C were calculated by totalling daily cumulative light intensity and average temperature. A new index (D) was defined as the normalised variation of An,C, IC, and Ta,C, and a statistical analysis was conducted on the means for each index. The results showed that An,C had the lowest D (0.114), suggesting that it was a better index for predicting the time of harvest. This study suggests the importance of considering the accumulation of photosynthates in individual fruit, which cannot be achieved by IC or Ta,C, these results can be used to improve the forecasting and optimisation of yield. However, further research is required to substantiate these claims.