Response of Growth, Productivity and Quality For Some Faba Bean (Vicia faba L.) Cultivars to Different Irrigation Regimes

At experimental farm, faculty of agriculture, Menofia university, Egypt, a field experiment was conducted in 2021/2022 and 2022/2023 seasons to study the performance of growth, seed and water productivity as well as drought tolerance of six faba bean cultivars (Giza 3 , Giza 461 , Giza 716 , Sakha 1 , Sakha 3 and Sakha 4) to three different irrigation regimes (2, 3 and 4 irrigations). Results showed that decreasing number (no.) of irrigations from 4 to 2 caused a significant reduction in all traits studied, i.e. physiological attributes (total water content "TWC %", relative water content "RWC %"  and total chlorophyll "chl."), growth characters (plant height, number of leaves/ plant, leaf area / plant as well as leaves, stem and total dry weight/ plant) and seed yield/ feddan (fed) and its components (no. of pods / plant, no. and weight of seeds / pod, 100-seed weight and seed yield / plant) as well as the amounts of total used water/ fed, but caused an increase in seed protein % and saved water and water productivity/ fed in both seasons and their combined. Sakha 4 cv. significantly surpassed the other tested varieties in each of chl., most of growth characters, no. of pods / plant and seed yield/ plant and fed as well as water productivity/ fed. However, Giza 716 cv. was superior in TWC % and RWC %, but Sakha 1 cv. was superior in no. and weight of seeds/ pod than the other tested varieties in the two seasons and their combined. According to the combined analysis of both seasons, the interaction between the two tested factors showed generally that the highest values were obtained by Sakha 4 cv. for chl., plant height, leaf area / plant, total dry weight/ plant and no. of pods/ plant, Giza 716 cv. for RWC %, Sakha 1 cv. for no. of seeds / pod, Sakha 3 cv. for 100 seed weight and Giza 3 cv. for seed yield / fed when their plants were irrigated 4 times. In addition, Sakha 4 and Giza 716 are considered to be the most drought tolerant cultivars owing to having the lowest values of drought tolerance indices, i.e. tolerance index (TOL), relative yield reduction (RYR %) and drought susceptibility index (DSI) under drought stress conditions as compared with the other tested cultivars in this study.