Effects of Daily Light Integral on Compact Tomato Plants Grown for Indoor Gardening

Abstract

Our objective was to characterize the growth, physiological responses, fruit yield, and quality of tomato (Solanum lycopersicum L.) plants grown under different daily light integrals (DLIs) and photoperiods. In experiment I, nine compact tomato cultivars were grown indoors using broadband white light-emitting diode (LED) fixtures. Plants were grown under low (10.4 mol·m−2·d−1) and high (18.4 mol·m−2·d−1) DLIs with 12 and 16 h photoperiods, respectively, and two intermediate DLIs of 13.8 mol·m−2·d−1 with either 12 or 16 h photoperiods. In experiment II, three compact tomato cultivars were grown under the same low DLI with either 8 or 12 h photoperiods, and the same high DLI with either 12 or 16 h photoperiods. Generally, higher DLIs decreased plant growth and increased the fruit yield. Changing the DLI delivery strategy by adjusting the photoperiod and photosynthetic photon flux density (PPFD) did not have major effects on the growth, yield, and fruit quality of the compact tomato plants evaluated in this study, even though net photosynthesis increased under higher PPFDs in experiment II. Although several cultivars were affected by intumescence, only two cultivars showed treatment responses, for which the severity was generally higher in lower PPFDs using the same DLI.