Response of Rice Yield and Yield Components as well as Grain Quality to Number and Levels of Zinc Foliar Spraying Application

TWO field experiments were conducted during the summer season of 2014 and 2015 growing successive seasons at the Experimental Station of Faculty of Agriculture, Ain Shams University, Shalakan, Kalubia Governorate, Egypt, to investigate the response of rice crop yield and yield components as well as grain quality to the number (once, 45 DAS; twice, 60 DAS and thrice, 75 DAS) and levels (0, 200, 400, 600 and 800ppm Zn) of zinc foliar spraying application. Experimental design was split plot design with three replications, where, number of zinc foliar application occupied the main plots and zinc levels distributed in the sub plots. Application of 600ppm Zn gave the highest values of panicle number/m2, panicle length, spikelets numbers/ panicle, panicle weight, filled grains percent, filled grains numbers/panicle and 1000 grain weight. Foliar application of 600ppm Zn showed the highest values of grain crude protein content, soluble carbohydrate, GNY, SNY, TNY, NRE and NUE. Thrice zinc foliar application gave the maximum values of panicle length, spikelets numbers/panicle, panicle weight, filled grains percent and filled grains numbers/panicle. While, panicle number/m2 and 1000 grain weight were slightly affected by number of zinc foliar application. Application of thrice zinc foliar application at the level of 600ppm exhibited the highest values of grain, straw, biological and GCP yields as well as most of yield attributes and nitrogen physiological parameters.