Kaolin Foliar Application Enhanced Physiological Functions and Pods Quality of (phaseolus vulgaris L.) under Deficit Irrigation Regimes

Document Type : Original full papers (regular papers)

Authors

1 Horticulture Department, Fayom Uni.

2 Horticulture Department, Faculty of Agriculture, Fayoum University, 63514-Fayoum, Egypt.

3 Department of Vegetable, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria 21545, Egypt

4 Horticulture Department, Faculty of Agriculture, Fayoum University, 3. 63514-Fayoum, Egypt.

Abstract

Two field experiments were consecutively conducted during the fall seasons of 2018 and 2019 to examine the main and interactive effects of kaolin foliar application (Kao) and deficit irrigation (DI) at different physiological stages on physiological functions and pods quality of (phaseolus vulgaris L.). DI has been applied by skipping one irrigation at different physiological stages (DI-Vegetative growth, DI- Flowering and DI-Ripen) plus normal watering, as a comparison treatment. Kao-C foliar spray has been applied with different concentrations (without kaolin, Kao-1= 12.5 g / L and Kao-2 = 25 g / L) weekly after the first irrigation till the ripening time (a total of five times). The experimental layout was a Split-Plot System depending on Randomized Complete Blocks design with 3 replications. DI occupied the main plot and Kao foliar application allocated at the sub-plots. Kao foliar application enhanced drought stress tolerance in common bean plants by improving photosynthetic efficiency (Fv/Fm and PI) and plant water status as evaluated by membrane stability index and relative water content. The results showed that skipping one irrigation either DI-vegetative or DI-ripen combined with foliar spraying of kaolin (Kao-1 or Kao-2) had a noticeable positive effect on leaves chemical contents (N, P, K, chlorophyll, carotenoids and TSS) and plant water status (relative water content (RWC) and membrane stability index (MSI)), as well as pods chemical contents (N, P, chlorophyll, carotenoids, TSS), and fruit firmness.

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