The effect of interaction between humic acid and water stress in the content of wheat leaves from proline and some of its components

A field experiment was conducted for the cultivation of wheat crop Triticum aestivumL. in one of the fields belonging to the extension farm experiments in Al-Mahnawiyabelonging to the Extension Center in Babylon province during the winter season (2017-2018)to study the effect of adding humic acid in wheat bearing to water stress during branchingstage and grains filling stage, In the experiment, three levels of humic acid were used (0: Thecontrol treatment, 20 kg.ha-1: Added to soil, 10 ml.L-1: Sprayed on the plant) which aresymbolized by (H0, H1, H2), respectively. Three water stresses were also used: S0 is thecontrol treatment, (S1) stopping irrigation in the branching stage, (S2) stopping irrigation inthe grain filling stage. The experiment was applied within the classification of theRandomized Complete Blocks Design (R.C.B.D), in the order of split plots, with threereplicates. Wheat seeds (Aba 99 cultivar) were cultivated which obtained from AgriculturalResearch Station in Babylon. Concentrations of nutrient elements have estimated of nitrogen,phosphorus and potassium in post-harvest soil. Plant height, number of branches, weight of1000 grains, Biologic yield, grain yield and harvest index, concentrations of nutrient elements(N, P, K) in grain, Protein and Leaves content of K were also estimated. The depth ofirrigation water and its date were determined depending on the moisture of the soil andaccording to the depth of the plant root system . the results were as follows: The sprayingtreatment with humic acid (H2) was significantly excelled in most of the growth traits ofwheat yield compared with the control treatment which gave (14.55 tons.h-1). The water stressat the grain filling stage (stopping irrigation) led to a significant increase in the leaves contentof the proline compared to the two stages of water stress in the branches stage (S1) and nonstress (S0). Water stress (S0) led to a significant increase in grain yield of (6.33 tons.h-1),which did not differ significantly from the treatment of water stress in the branching stage(S1), which amounted to (5.89 tons.ha-1) while the increase in the S0 treatment was comparedto the stopping irrigation treatment S3 in the grain filling stage, which amounted to (5.50tons.h-1), an increase of 15.09%. The interaction treatment (H2S0) gave the highest values andfor most of the study indicators of (16.10 and 6.60 tons.ha-1 Biologic yield and grain yield,respectively, 38.61 g weight of 1000 grains). The interaction treatment (H2S3) gave thehighest harvest index of 42.99% while the H1S3 treatment gave the highest leaves content ofproline acid (3.10 mg.g-1).Research paper from MSC