THE EFFECT OF AIR TEMPERATURE ON FRUIT YIELD OF SWEET PEPPER (CAPSICUM ANNUUM) GROWN UNDER PLASTIC HOUSES IN EGYPT

Sweet pepper, Capsicum annuum, cv. Gedeon is one of the major crops grown under plastic houses in Egypt. The experiments were carried out at El-Bosaily a protected cultivation site, in the Northern Coast of Egypt, for the two successive growing seasons of 1989/90 and 1990/91. Several treatments, i.e., warm air, water tubes, and straw were used in order to increase the night temperature in a plastic house as compared to the control, non-heated plastic house. Results obtained proved that any increase in night temperature resulted in a considerable increase in fruit yield. Incremental cost, profit and benefit-cost ratios were estimated for each treatment. The heating treatment proved the importance of improving night temperature in increasing crop yield. Warm air showed a lower benefit-cost ratio than the control due to the high initial and running costs in spite of having much higher yields than the control.