Aomori hiba essential oil (AO) inhibits ethylene production in fruit and vegetables. In this study, the properties of gelatin (GE)/konjac glucomannan (KGM)-based coatings and films incorporating 5%, 25%, and 50% (w/w of polymer) AO were investigated. The base of the coating solution (GK) was a mixture of 1% (w/v) GE solution and 1% (w/v) KGM solution at a ratio of 7:3. The AO/GK films showed extremely low gas permeability to O₂ and CO₂ compared to general modified atmosphere packaging. The microstructures of the AO/GK films observed via scanning electron microscopy (SEM) indicated a reduction in the barrier properties of the films due to pores formed by the volatilization of AO. The effect of the AO/GK coating on ethylene production in peaches (Prunus persica (L.) Batsch, cv. ‘Hikawa Hakuho’) during cold storage was also examined. The surface of the coated peach skin was covered with the coating and the stomata were sealed. The GK coating without AO and with low concentrations of AO suppressed ethylene production during storage at 10℃. Based on these results, we concluded that AO5/GK is the most applicable coating agent for maintaining the freshness of fruits and vegetables.

　Predicting the yield of horticultural crops is crucial to meet the expectations of retailers and consumers. In this study, we developed random forests (RF) based on the measured amounts of whole-plant photosynthesis and transpiration to predict cherry tomato fruit yields in a commercial greenhouse in Japan. Whole-plant daily net photosynthesis (Photo) and daily transpiration (Trans) were measured by using a real-time photosynthesis and transpiration monitoring system. Variables of environmental conditions (Env), including daily solar irradiation, air temperature, and atmospheric water vapor deficit, were also measured in the greenhouse. Data with different 7 variable combinations (Env, Photo, Trans, Env+Photo, Env+Trans, Photo+Trans, Env+Photo+Trans) and different 21 timeframes (from 1 to 6 consecutive weeks in the past 6 weeks) were used to train models for predicting the yield for the subsequent week. RF models with the timeframes of 3 consecutive weeks until 2 weeks before the date of yield prediction (3W2) and 4W2 and variable combinations of Photo, Env+Photo, and Photo+Trans had relatively low normalized root mean square error (RMSE%; 9.8-10.3%). The model that had a timeframe 4W2 and variable combination Photo had the best accuracy (RMSE% ＝ 9.8%). These indicate that whole-plant photosynthesis and transpiration are good predictors of cherry tomato yield.

　To control the harvest date of strawberries, we constructed a device that can control the local fruit temperature and investigate the effects of fruit cooling and heating on fruit maturation and quality. Fruits were sequentially placing into thermally insulated tubs to control the local temperature during fruit development. The average fruit temperature decreased by 4.1℃ during fruit cooling and increased by 3.8℃ during fruit heating when compared with fruit without local temperature control. The number of days from flowering to harvest (i.e., days to maturation) was strongly affected by fruit temperature, with fruit cooling prolonging and fruit heating shortening the days to maturation when compared to the control. Non-linear regression analysis revealed two regression formulas for predicting days to maturation from the average fruit temperature. When compared to the fruit without local temperature control, fruit size, soluble solids content and dry matter ratio decreased significantly with fruit heating, while in contrast, no differences were observed for these quality parameters with fruit cooling.

　Ascorbic acid (AsA) is an essential phytonutrient, and tomatoes are an important dietary source. Tomato fruit AsA content is regulated by light conditions and is cultivar-dependent, but their regulations is unknown about the role of source-sink relationships. This study was designed to compare the light/dark-controlled regulation of AsA between intact (plant-attached fruits with source-sink relationships) and in vitro culture (plant-detached fruits without source-sink relationships) tomato fruits of five cultivars. Compared with fruits grown under light conditions, AsA content was lower in both intact and in vitro fruits grown in the dark; however, the decrease in AsA in the dark treatment was markedly lower in intact fruits (17-29%) than in vitro fruits (44-74%) and was dependent on the cultivar. Antioxidant enzyme activities and lipid peroxidation were lower under the dark condition in in vitro fruits (30-90%) but not intact fruits. Therefore, the reduction of AsA content under darkness occurred due to decreased in situ biosynthesis and antioxidant system activity in fruit without source-sink relationships. Furthermore, the reduction of AsA content induced by darkness was mitigated by source-sink relationships, as indicated by the intact fruit results, and their effects depend on cultivars.