Response of three okra ( Abelmoschus esculentus L. Moench) cultivars to irrigation at specific growth stages

Abstract

The effects of water stress at the vegetative, flowering and pod-filling stages of three okra cultivars, ‘Lady Finger’, ‘Kano Dwarf’ and ‘Awgu Early’, on fruit yield, yield components and nutrient uptake were investigated in a pot experiment. The greatest percentage reduction in fresh fruit yield occurred when moisture stress was imposed at the flowering stage of ‘Kano Dwarf’ and ‘Awgu Early’ and the pod-filling stage of ‘Lady Finger’. In all cultivars, moisture stress at both the flowering and pod-filling stages resulted in a reduction of more than 70% in fruit yields, while the lowest reduction in fruit yield occurred with moisture stress during the vegetative stage. The stress index values (which reflected the actual crop stress responsible for reducing the potential yield of the cultivars) were inversely related to fruit fresh and dry masses and total dry matter yields, and revealed an order of tolerance to moisture stress of ‘Kano Dwarf’ > ‘Lady Finger’ > ‘Awgu Early’. The concentrations of N, P, K, Ca and Mg in the fruits were dependent on both cultivar and stage of moisture stress. Moisture stress increased the uptake of N and K in all cultivars. Between cultivars, the highest concentrations of crude proteins, total N, available P and K were in ‘Kano Dwarf’.