Improved water use efficiency and yield of drip-irrigated pepper under full and deficit irrigation conditions

Abstract

N EGYPT, water scarcity is the main problem the agricultural sector faces. Salicylic acid (SA) as a plant growth regulator may help mitigate the adverse effects of deficit irrigation water on pepper plants. Sweet pepper (cv. S702 F1) plants subjected to deficit irrigation (DI 40% = 60% of crop evapotranspiration, ETc) regularly during growth stages produced decreases in plant height, total chlorophyll, fruit number per plant, fruit length, fruit diameter, fruit volume, fruit yield, fruit carotenoids, and total dry matter comparing with the full irrigation (FI= 100% of ETc). However, water use efficiency (WUE), proline, free amino acids, ascorbic acid, total sugars, total soluble solids (TSS), total phenols content (TPC), total flavonoids content (TFC), and nitrate content were enhanced under deficit irrigation conditions. The results showed that under FI or DI 40% with foliar application of SA at 1.0 mM was more effective than 0.5 and 1.5 mM in improving vegetative growth and yield parameters. However, FI produced the highest significant values of plant height, total chlorophyll, fruit yield, carotenoids, and total dry matter. Conversely, the pepper plant's ability to withstand DI 40% was enhanced by the 1.0 mM SA treatment, which resulted in the highest accumulation of ascorbic acid, total sugars, TSS, TPC, and TFC. Moreover, the application of SA significantly increased WUE and decreased fruit nitrate content. It could be concluded that the foliar application of SA can alleviate the detrimental effects of deficit irrigation on pepper plants.