Effect of light and temperature on the phenology and maturation of the fruit of eggplant (Solanum melongena) grown in greenhouses

Abstract

This study aimed to determine relationships for the effect of light (between 3 and 7 MJ/m(2) per day) and temperature (between 12 degrees C and 28 degrees C) on some developmental and fruiting parameters such as days to first flowering (FD, days), flower bud number/plant (FBN/P), fruit number/plant (FN/P), mean fresh fruit weight/plant (MFFW/P, g), fruit growth period (FGP, days), and total yield/plant (TY/P, g) of eggplant (Solanum melongena) grown in greenhouses. All parameters except days to flowering and fruit growth period showed a sharp curvilinear response to temperature at all light intensities, with lower values either side of an optimum temperature. Days to flowering showed little response to temperature at 7 MJ/m(2) per day of light but decreased with temperature at 3 MJ/m(2) per day. Optimum temperature for each attribute increased with increasing light intensity except for flower bud number. FD, FN/P, and TY/P showed a slight curvilinear response to light intensity at all temperatures except that days to flowering and fruit number per plant showed a sharp curvilinear decline at higher temperatures. FBN/P and MFFW/P showed a sharp linear response to light intensity at lower temperatures and a slight curvilinear response at higher temperatures. At all temperatures, FGP was a sharp linear function of light intensity. The derived relationships provide the potential for optimising growth and fruiting of eggplant in greenhouses, but need to be validated under commercial conditions.