Production and quality of the onion crop (Allium cepa L.) cultivated under controlled deficit irrigation conditions in a semi-arid climate

The experiment discussed below was carried Out on an onion crop cultivated under controlled deficit irrigation (CDI) conditions in a semi-arid climate. Eight treatments were used in which different water doses were applied according to the water requirements at each stage of the crop cycle. The effect of water deficit was studied at three vegetative stages (development, bulbification and ripening). Although, the dry matter yield was not affected by the total volume of water intake (with volumes ranging from 603.1 to 772.0 mm), the statistical analyses made have shown that there is some interaction between the volumes of water received by the crop at the bulbification and ripening stages, which means that inducing a shortage in both stages at the same time does lead to significant differences in the yield obtained. As to bulb sizes, the treatments which received the greatest volumes of water during the development and ripening stages yielded harvests with higher percentages of large-size bulbs, whereas the water shortages induced during the growth and bulbification stages led to higher percentages of small-size bulbs. (C) 2004 Elsevier B.V. All rights reserved.