Response of fig seedlings cv. Aswad Diyala to biochar application and tryptophan foliar spray

Fig is an ancient fruit that grows well in hot and dry climates, making it well-suited to the prevailing climatic conditions in Iraq. It contains many health benefits, including improving digestion, lowering cholesterol levels and providing a variety of vitamins and minerals. Additionally, fig cultivation is an important source of income for many farmers in Iraq, contributing to local economic development. The experiment was conducted in the lath house of the Department of Horticulture and Landscape Gardening, College of Agriculture, University of Anbar. The study period extended from March 15 to November 15, 2024 and aimed to investigate the effects of applying reed biochar at three levels (0 %, 2 % and 4 %), denoted as B0, B1 and B2, respectively and foliar spraying of the amino acid tryptophan at four concentrations (0, 50, 100 and 150 mg L-1), represented as T0, T1, T2 and T3, on selected vegetative and root growth traits of fig seedlings of the 'Aswad Diyala' cultivar. A total of 108 seedlings with uniform vegetative growth were selected. The study was laid out in a 3 × 4 factorial experiment using a Completely Randomized Block Design (CRBD) with 12 treatment combinations, three replications and four seedlings per experimental unit. A two-factor 3 x 4 factorial experiment was implemented according to a CRBD. The experiment contained 12 treatments, three replicates and four seedlings per experimental unit. The addition of reed biochar significantly affected all the traits studied, with the highest level (B2) showing the most notable improvements. It led to a marked increase in seedling height, number of vegetative branches, stem diameter, leaf count, dry weight of both vegetative and root systems and leaf area. Similarly, foliar spraying with the amino acid tryptophan had a significant impact on all traits, with the highest concentration (T3) achieving the best results in terms of seedling growth, leaf development and dry matter accumulation. The interaction between biochar and tryptophan treatments also showed significant effects on most of the traits, with the B2T3 combination yielding the best results for many of the parameters, while the control treatment (B0T0) exhibited the lowest values across all traits.