Abdel C. G. J. of Tikrit Univ. For Agric. Sci. 2007 Vol 7, 1:254- 261 254 WATER RELATIONS IN FABA BEAN (Vicia faba L. cv. Aquadulce) 1- INFLUENCE OF GIBBERELLIC ACID (GA 3 ) APPLICATION ON GROWTH AND YIELD OF GREEN PODS Caser G. Abdel caserabdel@yahoo.com Horticulture Dept, College of Agriculture college Duhok University, Duhok, IRAQ ABSTRACT This experiment was carried out during 2001-2002 growing season at Yarimja field, Mosul City to investigate the possibility of improving growth and yield of green pods of rainfed and supplementary irrigated faba bean plants by foliar spraying of GA 3 rates of 0, 50, 100, and 150 mg.L‾¹. The results showed that supplementary irrigated faba bean whenever 25% of soil AWC to a depth of 30cm was depleted substantially exceeded these of rainfed in most detected traits particularly yield of green pods by 27.6%. Moreover, it delayed pod maturation. 50 mg.L‾¹ GA 3 was the most effective rate under supplementary irrigation, however, under rainfed 150 mg.L‾¹ GA 3 was the superior rate. Since these two rates gave the highest yield of green pods (2.15 and 1.88 kg.m -2 , respectively). GA 3 application tended to lengthen juvenility and delayed pod maturation and its combination with supplemental watering led to plant lodge particularly with 150 mg.L‾¹ GA 3 rate, albeit their yield improvement. Under rainfed cultivation, 150 mg.L‾¹ GA 3 rate profoundly increased drought resistance ability, but it failed to face earlier maturity brought about by drought episodes. INTRODUCTION Grain legume crops are an important component of food production system. These crops are very adaptable, produce protein rich edible material and fix atmospheric nitrogen through symbiosis (Carangal, et al., 1987). The principle factor affecting growth, yield and nitrogen fixation is considered to be soil moisture in tropic (Patanothai and Ong, 1987). Faba bean is widely grown in the Mediterranean rejoin and to a lesser extent in central and northern Europe. Its small seeded cultivars (Minor) are mainly used as animal fed, whereas large seeded cultivars (Major) are used for human consumption (Kittlitz, 1993). Supplementary irrigation in north Iraqi provinces, particularly in Mosul desperately required in order to obtain faba bean yield of high quality, owing to the yearly irregular rainfall incidences and even among months of the same year (Abdel, 1993). Faba bean is an important pulse crop in areas with more than 400 mm average annual rainfalls (Agunge and Mc Donald, 1998). Gibberellic acid (GA 3 ) do influence the capacity of plant to flower, stem elongation as well as sexual characteristics of flower and subsequently fruit development (Hopkins, 1999). Therefore, an attempt was made to find out the ability of GA 3 foliar application in improving the growth and yield of green pods of Aquadulce faba bean cultivar grown under rainfed and supplementary irrigation. Materials and Methods This experiment was carried out at Yarimja vegetable field during the growing season of 2001-2002 to investigate the possibility of improving growth and yield of green