RESPONSE OF WATER REQUIRMENT AND LECTTUCE YIELD TO WATER STRESS AND PROLINE FOLIAR UNDER DRIP IRRIGATION SYSTEM

Abstract

A field experiment was conducted to grow lettuce (Lactuca sativa L.) during the 2021-2022 season in Al-Yusufiyah district, south of Baghdad, to study the effect of irrigation levels and spraying with proline acid on water requirements, growth and production of lettuce. The experiment was designed using a complete randomized block design (RCBD) and included two factors: the first factor (irrigation levels) includes three treatments (irrigation after depletion 25, 40 and 55% of the available water) and the second factor (concentrations of adding proline acid sprayed on the leaves) includes three treatments (not adding proline and adding proline sprayed on the leaves at a concentration of 40 and 80 mg L^-1). The results of the study were as follows: Seasonal water consumption reached 262, 233 and 186 mm for the moisture depletion treatments of 25, 40 and 55% of the available water, respectively, under the drip irrigation system. The total vegetative yield of lettuce was 247.67, 215.10 and 171.73 μg ha^-1 at 25, 40 and 55% depletion levels of available water, respectively. The total yield of lettuce was 258.30, 228.50 and 181.40 μg ha^-1 at 25, 40 and 55% depletion levels of available water, respectively, when spraying proline acid at a concentration of 80 mg L^-1.