INFLUENCE OF SEED HARDENING TREATMENTS ON YIELD, YIELD ATTRIBUTES AND NITREOGEN PHYSIOLOGICAL PARAMETERS OF MAIZE (Zea mays, L.) UNDER DROUGHT STRESS CONDITIONS

Two field experiments were carried out in Agric. Expt. Farm, Fac. of Agric., Ain Shams Univ. at Shalakan, Kaleobia Governorate, Egypt during 2013 and 2014 growing seasons. These experiments aimed to study the effect of seed hardening treatments (without, -4 bar, -6 bar and  -8 bar polyethylene glycol (PEG6000)) on yield and its attributes and nitrogen physiological parameters of maize (zea maize) under irrigation periods (irrigation every 14, 21 and 28 day) . The data revealed that all tested treatments affected significantly yield and its attributes traits except ear length. The highest values of ear weight (246.2 g), ear diameter (4.62 cm), number of rows/ear (13.6), shelling percentage (82,64%), grain yield/fad (3.58 ton), biological yield/fad (11.81 ton) and 100 kernels weight (g) (39.07) were recorded with -8 bar (PEG) treatment. Moreover -8 bar (PEG) this treatment recorded the highest values of grain nitrogen yield (kg/fad) and lowest value of grain nitrogen percentage (%). Irrigation every 14 days was characterized by significant higher yield attributes, which reflected its yield parameters and produced significant maximum grain yield. Irrigation every 14 day recorded significant highest grain and biological yield, which reflected its grain N yield and total N absorbed in plant. Maximum values of NUE and NRE ware optioned when maize plant irrigated every 14 day followed by irrigation every 21 day and irrigation every 28 day. On the other hand, NPE and NHI of studied irrigation periods were significantly differed; the highest values were recorded when maize irrigated every 28 day. The results also showed that seed hardening treatments (-4, -6 and -8 bar PEG) under irrigation periods 14 and 21 day recorded the highest values of ear length (cm) and ear diameter (cm). The high performance of irrigation every 14 day with hardening -8 bar PEG in yield attributes was reflected on its yield parameters. These parameters reached their highest significant values included grain and biological yield ware 3.97 and 13.55 ton/fad respectively; meanwhile; the lowest values in case of without hardening under irrigation every 28 day ware 2.17 and 7.84 ton/fad respectively .