Yield, fruit quality and physiological responses of melon cv. Khatooni under deficit irrigation

To evaluate the effect of water deficit stress on growth, yield, fruit quality and physiological traits of melon cv. Khatooni, field experiments were conducted in split plot randomized complete block design with three replications. In 2014, irrigation treatments consisted of two deficit irrigation regimes, 33% and 66% of ETc (crop evapotranspiration), and 100% ETc as the control (DI33, DI66 and I100). In 2015, irrigation treatments applied were: 40, 70 and 100% ETc (DI40, DI70 and I100). The results showed that plant height and leaf area decreased from treatment I100 to DI40 and DI33. The highest average fruit weigh and yield were obtained from irrigation 100% ETc for both years. The water use efficiency (WUE) significantly increased in response to increase water deficit stress. Deficit irrigation treatments significantly decreased leaf relative water content, vitamin C and fruit firmness, whereas antioxidant enzymes activity, proline and total soluble solid contents increased. These results suggest that the crop is sensitive to water deficits, that moderate water stress (DI70 and DI66) reduced yield by about 28.5-38.2% and severe water stress (DI40 and DI33) had a much more marked effect, reducing yield by 48.1-61.4%

Evaluation of Growth, Yield and Vitamin C Content of Okra with Application of Putrescine and Humic Acid Under Deficit Irrigation Stress

In order to study the effects of putrescine (Put) and humic acid (HA) on growth, yield and pod quality of okra (Abelmoschus esculentus L. 'Kano') under deficit irrigation stress, the field experiment was conducted in split plot based on randomized complete block design with three replications. Three different irrigation regimes (33, 66 and 100% ETc) and foliar application of Put (0, 0.5, 1 and 2 mM) and HA (0, 150 and 300 mg.l-1) were conducted. The results showed that deficit irrigation significantly decreased growth, yield and vitamin C content. Significant (P>0.05) increase in growth and yield was observed with the application of both HA and Put. The highest plant growth was obtained whit application of HA 300 mg.l-1 and Put 1mM under irrigation 100% ETc. Also, the maximum yield was observed whit foliar application of HA 300 mg.l-1 and Put 1mM under irrigation 100% ETc. Application of Put and HA at irrigation 100% ETc and HA 150 and 300 mg.l-1 and Put 1mM under deficit irrigation 66% ETC had highest effects on vitamin C content. According to the results, application of HA 300 mg.l-1 and Put 1mM can be proposed to improve growth and yield of okra

The mechanism of enhancing drought tolerance threshold of pepper plant treated with putrescine and salicylic acid

Pepper is a warm-season crop and water deficit is considered as dominant issue in pepper cultivation. Using plant growth regulators in different steps of plant growth and development could be as useful strategy to overcome adverse effects of abiotic stresses. In order to investigate the morpho-physiological responses of pepper plant to putrescine (Put) and salicylic acid (SA) foliar application and deficit irrigation (DI) strategy, the split plot experiments were laid out based on randomized complete blocks design at University of Zanjan. The highest values of leaf area and total yield were recorded in sprayed plants by Put at 1.5 mM under DI0% (5842 cm2 and 9.6 ton ha−1). SA at 1.5 mM was the best treatment to increase vitamin C content of pepper fruits. Free proline content increased by 41.34% in sprayed plants by Put at 1.5 mM (7.5 µm g−1 FW) compared to control. SA treatment increased number of pepper fruits, size of harvested fruits and total produced yield by regulation of stomatal conductance and increasing leaf chlorophyll content of pepper plants under drought stress conditions. Also, Put foliar treatment increased drought tolerance rate of pepper plant by increasing free proline content, peroxidase enzyme activity and water use efficiency and also applying this treatment could significantly reduce electrolyte leakage rate. So, SA and Put foliar application at 1.5 mM concentration could be recommended as widely used technique to overcome adverse effects of drought stress on pepper plants cultivated in arid and semi-arid regions