Light intensity and spectral quality affect fruit growth and shelf life of greenhouse-grown long English cucumber

The importance of light intensity and spectral quality on fruit color and shelf life of long English cucumber (Cucumis sativus L.) was studied in four greenhouse experiments, The intensity of cucumber greenness was measured nondestructively by video imaging, and shelflife was measured by visual observation of incipient yellowing. In the summer, filters were used to cover individual fruit to reduce light intensity reaching the fruit surface, The lower the light intensity incident on a cucumber, the shorter its shelflife. The average shelflife was 8, 5, or 1 days for cucumbers receiving 100%, 66%, or 31% of natural daylight, respectively, The fruit that were covered with a filter transmitting red (R) light were greener (low grey level via video imaging) than those with a far-red (PR) filter, In the fall, fruit receiving spectral R lighting from fluorescence tubes were greener and had a longer shelflife than those receiving FR lighting from incandescent bulbs, in the winter, high-pressure sodium (HPS) fighting was necessary to supplement natural daylight for crop growth and production. Under HPS, R and FR lighting produced the same fruit greenness and shelflife,In the spring, R-lighted fruit had longer shelf life than PR-lighted ones, although fruit color at harvest was similar In these four experiments, postharvest shelflife of long English cucumber was generally related to fruit greenness upon harvest, The data suggest the importance of an open canopy in improving fruit greenness and shelflife of greenhouse-grown cucumbers.