Effects of Humidification Based on Vapor Pressure Deficit (VPD) on Plant Growth, Fruit Yield, and Fruit Quality Traits in June-bearing Strawberry

Abstract

To develop novel humidification technology for strawberry production to achieve higher yields and improve fruit quality, four Japanese June-bearing strawberry cultivars were grown in a greenhouse with or without humidification treatment (HT) based on vapor pressure deficit (VPD). HT reduced VPD from transplanting to March, but did not affect the VPD condition from April to May. Soon after transplanting, HT enhanced plant growth and the daily leaf-emergence rate, and significantly advanced flower-bud emergence and first-fruit harvest for the first inflorescence for ‘Koiminori’, ‘Kaorino’, and ‘Saga i9’. However, HT significantly delayed flower-bud differentiation and first-fruit harvest of the second inflorescence of ‘Kaorino’ and ‘Yumenoka’. HT significantly increased the total weight of marketable fruit for ‘Koiminori’, ‘Kaorino’, and ‘Saga i9’. In addition, HT significantly increased the total fresh weight of marketable fruit harvested until December for ‘Koiminori’ and ‘Saga i9’. HT did not significantly affect the firmness of fruit skin (FFS), soluble-solid content (SSC), fruit acidity (FA), or SSC/acidity of ‘Koiminori’, ‘Kaorino’, and ‘Yumenoka’.