2022 Volume 91 Issue 4 Pages 531-540
Postharvest blossom-end enlargement (BEE) in summer cucumber has a serious economic effect in Japan. Previous studies suggested that BEE is influenced by cultivation conditions and temperature during transportation. In this study, the relationship between postharvest BEE and growth parameters in plants under various sink–source balances created by defoliation and fruit thinning was determined using a growth analysis technique. Cucumber (Cucumis sativus L. ‘Taibo I’) seedlings were transplanted into an outdoor field at Ibaraki University in 2019, and the harvested fruits were stored in plastic bags at 27°C. The occurrence of BEE, which was scored six days after harvest, was positively correlated with the field air temperature and cumulative duration of sunshine exposure from flowering to harvesting. Furthermore, high temperatures and extended sunshine exposure reduced the time from flowering to harvesting. However, excessive defoliation reduced BEE occurrence, most likely because of the increased time from flowering to harvesting, suggesting that early fruit maturation may be one of the causes of BEE. Therefore, principal component analysis was performed to understand the relationship between growth parameters and the occurrence of BEE in cucumber. The occurrence of BEE increased when the sink–source balance was inclined towards the source. Collectively, these findings indicate that high temperatures, extended exposure to solar radiation, and large leaf area with respect to the number of fruit set increase the occurrence of BEE, with pre-harvest fruit maturity probably related to its onset.
