Abstract

Lodging of rice in Egypt reduces production and may be related to the agronomic practices. A 2-years field experiment was conducted at the Experimental Farm of Rice Research and Training Center, Kafr El-Sheikh, Egypt, during two growing summer seasons of 2013 and 2014 to study the effect of growth regulators application at different nitrogen levels on lodging resistance and productivity of Sakha102 rice cultivar. Nitrogen levels 0, 110 and 165 kg N ha^-1 in the form of urea (46.5%N) were allocated in the main plots while, growth regulators and potassium sulfate (48% K₂O) were allocated in the subplots. Growth regulators (Cycocel and benzyladenine) and K₂O were applied as foliar application at 15 and 30 days after transplanting. Cycocel, benzyladenine and K₂O were applied at the concentration of 80 ppm, 15 ppm and 2%, respectively. Data indicated that most of the studied characters increased significantly by nitrogen and growth regulators application. Application of nitrogen increased lodging area, while application of different growth regulators reduced the rice lodging area especially at the high level of nitrogen. Leaf area index at 50 days after transplanting (DAT), plant height (cm) at harvest, number of panicles m^-2, grain yield t ha^-1 and NPK uptake were correlated significantly and positively with lodging area percentage, while 1,000-grain weight (g) correlated significantly and negatively with lodging area percentage.

Key words: Lodging, growth regulators, benzyladenine, cycocel, nitrogen, potassium.