Abstract
The problem of water scarcity is currently one of the inhibitory factors affecting crop production and adaptation. In Lebanon, the adoption of a suitable irrigation system for annona cultivation is still unpracticed. Therefore, this study aims to compare drip and mini sprinkler irrigation systems in order to recommend the optimal one. The experiment was done during two consecutive years 2017-2018 on sugar apple (Annona squamosa L.) scion cleft grafted on cherimoya (Annona cherimola Mill.) rootstock. Water requirement of annona was calculated and applied through mini-sprinkler and drip irrigation. The vegetative and reproductive growth of irrigated trees were compared to those of non-irrigated trees (control). As a result, in the second experimental year, plant height, leaf number, leaf area and internodal length were significantly higher in the trees irrigated by drip compared to the control respectively by 40cm, 20leaves, 8cm(2) and 1.7cm. In addition, a significant improvement in flower number and diameter of primary roots and number of secondary roots was observed following mini-sprinkler irrigation compared to control. Fruit weight and number were most significantly improved by drip irrigation system by 10 fruits and 77g compared to control. However, in both experimental years sugar apple trees irrigated by drip system yielded the most (31 kg in the second year) compared to the remaining treatments (29kg for trees irrigated by mini-sprinkler and 22kg for the control in the second year). The choice of both systems improved all growth traits of sugar apple and ameliorated the adaptation of this culture to Lebanese conditions.