Effect of indole-3 Butyric acid (IBA) foliar application on growth, bulb yield and allicin of garlic (Allium sativum L.) under water deficit stress in field

Drought stress is the most important factor which negatively affects the plant growth and crop productivity in arid and semi-arid areas. The main problem which Iranian farmers are faced with cultivation of garlic (Allium sativum L.) is low production efficiency and performance. Therefore, in a field experiment, the effect of IBA (0 and 100 ppm) was studied on growth parameters, bulb yield and allicin content of a local garlic cultivar under water deficit conditions (40% reduction of available water) in 2010 in Jiroft. The results showed that drought stress significantly reduced chlorophylls (a, b and total), caretenoids, anthocyanins, bulb and allicin yield, plant fresh weight, root fresh weight and also increased ion leakage. However, it had no significant effects on the percentage of allicin. In contrast, under non-stress conditions, IBA significantly improved most recorded parameters and reduced ion leakage and amount of anthocyanins while it had no effect on product quality and quantity under water deficit conditions. Compared with the controls, IBA increased plant fresh weight, bulb yield, and allicin respectively by 30%, 19% and 25%.