Improving Growth and Productivity of Faba Bean Plants by Foliar Application of Thiourea and Aspartic Acid

Two field experiments were carried out at the Research and Production Station of the National Research Centre, Noubaria, Egypt, during the winter season of 2010/2011 and 2011/2012. This study aimed to investigate the response of vegetative growth, yield and some metabolic constituents of field bean (Vicia faba L. var minor) cv. Giza402 to foliar application of bio-regulator Thiourea (TU; 250, 500 or 1000 mg L-1), and amino acid Aspartic acid (AspA; 50, 100 or 150 mg L-1) either alone or in combination. Foliar application of TU and Asp A either alone or in combination significantly increased the values of number of branches, leaves and pods/plant, total dry weight/plant, leaf area index, specific leaf weight and crop growth rate criteria. Total photosynthetic pigments content in leaves were increased by increasing TU (up to 1000 mg L-1) and Asp A (upto150 mg L-1) singly or in combination. Straw, seed and biological yields of faba bean plants were significantly increased by increasing TU and Asp A concentrations up to 1000 and 150 mgL-1, respectively. Application of 1000 mgL-1 TU, singly and combined with Asp A at 150 mg L-1 caused significant increments in harvest index (2.9 and 25.5%) and seed yield ha-1 (46.4 and 101.9%), respectively, compared to their control plants. TU and Asp A, when applied alone, significantly improved the nutritional value and quality of faba bean seeds by increasing total carbohydrates, total crude protein, phosphorus, potassium, and calcium contents. In conclusion, foliar application of TU at 1000 mg L-1 and Asp A at 150 mg L-1, singly or combined could be recommended to improve the yield, nutritional value and quality of faba bean seeds.