Moreshet, S., Dept. of Environ. Phys. and Irrigat., Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Bet Dagan, Israel
Yao, C., Dept. of Environ. Phys. and Irrigat., Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Bet Dagan, Israel
Aloni, B., Department of Vegetable Crops, Institute of Field and Garden Crops, ARO, Bet Dagan, Israel
Karni, L., Department of Vegetable Crops, Institute of Field and Garden Crops, ARO, Bet Dagan, Israel
Fuchs, M., Dept. of Environ. Phys. and Irrigat., Inst. Soil, Water and Environ. Sci., Agricultural Research Organization, Bet Dagan, Israel
Stanghellini, C., Inst. of Agric. and Environ. Eng., Wageningen, Netherlands

The cracking of bell pepper fruit is one of the main physiological disorders that reduce marketable yield. Understanding the environmental and endogenous factors that influence this disorder may help to reduce its severity. Plants grown in three greenhouses were subjected to differing potential transpiration (Tp) at night, with identical daytime Tp. Measurements included climatic variables in the greenhouses, soil water content, sap flow, transpiration, leaf temperature, surface and internal fruit temperatures, fruit and stem diameters, stomatal conductance, and leaf area. The results show that at night pepper plants transpired at a rate proportional to the vapour pressure difference (leaves to air; VDP(1a)) in the respective greenhouses. The percentage of cracked fruits was highest in the greenhouse with the lowest night vapour pressure deficit (VPD) and lowest in the greenhouse with the highest VPD. Both increased direct radiation reaching the fruit surface and decreased soil water content reduced the growth rate of the fruit. Direct radiation and the temperature of the fruit inner space were well correlated with diurnal expansion and shrinkage of the fruit. The fruits with the higher expansion-shrinkage amplitude had more severe cracking symptoms. Decreased soil water potential counteracted the negative effect of direct radiation. These results indicate that the water status of the fruit is a key factor in determining the severity of fruit cracking. The implications of these results for greenhouse management in pepper production are discussed.