Determination of optimum levels of light irradiation needed to control ripening of tomatoes

Optimum levels of lighting parameters (light quality, irradiation time, and irradiance) and variety effect on inducing or delaying tomato ripening were identified by evaluations of specific physical and chemical characteristics using factorial designs. Under red light (R) or red plus blue light (R+B) irradiation, an irradiation time of 3 to 5 min at any level of irradiance tested was effective in accelerating red and yellow color development in tomatoes. With an irradiance of 38.90 W/m² under irradiation times of 3 to 5 min, far-red light (FR) was effective in delaying red and yellow color development. No combinations of treatments except variety had a significant effect on firmness. Light treatment effects on soluble solids content, pH, and titratable acidity were not consistent, but tomato variety had a significant influence on measured values of these properties.