S11 - Session P5 - Morphological and physiological analysis of poor development of strawberry fruits under mildly elevated temperatures

Authors: Saneyuki Kawabata *, Kazuya Higuchi

Strawberries is known to be susceptible to high temperatures. Even a mild temperature increase of about 2-4 ℃ above the optimal temperature, which is predicted due to global warming, is known to significantly inhibit receptacle development and reduce quality such as sugar content. In this study, we investigated the factors that lead to inadequate development of receptacles under mildly elevated temperatures. The size of receptacles was proportional to the number of achenes but was highly correlated with the number of mature achenes. Under the mildly elevated temperatures, the number of pistils per flower and the number of achenes per fruit were drastically reduced. However, the smaller fruit size was also associated with the enlargement of receptacles per achene, expressed as the average distance between achenes, and a shorter period of fruit development from flowering to receptacle maturation. Although the number of pistils is determined by the differentiation process of floral organs, mildly elevated temperatures were also found to affect the fruit development process after pollination. Strawberry is a non-climacteric fruit, and the fruit ripening is thought to be under the control of ABS, while the fruit development is controlled by auxin produced by achenes. The role of plant hormones in the poor development of strawberry fruits was discussed.