Two field trials were conducted at Giza Research Station, with split plot design with three replicates during the two successive summer seasons in 2012 and 2013. The aim of this study was to find out the effect of cotingen for covering seed by four treatments (zero, 7.5, 15 and 22.5 g kg-1 grain) and six nitrogen fertilizer levels (control, 30, 60, 90, 120 and 150 kg fed.-1) on maize yield and yield attributes of single cross 10 cultivar. Stepwise multiple linear regression analysis was used to determine the importance of yield components and to predict the yield under different levels of nitrogen and cotingen rates. Nitrogen levels exhibited significant effect for all studied traits, while cotingen were significant for100-kernels weight; shelling% and grain yield traits only. The interaction between cotingen and Nitrogen was significant for row per ear, shelling% and grain yield. Meanwhile, stepwise linear regression analysis showed that 100-kernels weight, number of kernels per row and shelling% were the most important contributing traits to yield (R2 = 82.11%). The nitrogen rates for maximum yield derived from the four statistical models (linear, logarithmic, quadratic, and exponential) describing the response of yield, using the R2statistic to select a model, which shows how each of the models fits the data. The quadratic model best described the yield responses observed in this study. Further confirms the role of nitrogen and cotingen fertilizers in increasing yield production in maize. The 5th N rate under 3rdcotingen (120 Kg fed-1 + 22.5 and 15g kg-1 grain) produced the highest yield being 34.70 and 34.65 ard. fed-1 over all treatments. This is very close to recommendations. The 4th N (90Kg fed-1) rate under any cotingen level produced higher yield than any nitrogen rate only. Economically, considering optimum N fertilization rate, 105.18 Kg fed-1 nitrogen and 22.5 g kg-1 grain cotingen was the most reasonable level. This is considerably below the current recommendation. Therefore, results confirmed that higher cotingen treatment decreased the optimal nitrogen and increased the yield.

The beneficial effects of boron, zinc and active dry yeast on yield and fruit quality of Zaghloul date palm grown at the Experimental Orchard, Faculty of Agriculture, Assiut University, Egypt was studied during 2011, 2012 and 2013 seasons. The experiment was set up in a complete randomized block design with ten replicates each of one bunch. All treatments were sprayed two times after fruit set and one month later. The obtained results could be summarized as follow: -       Boron, zinc and active dry yeast sprays significantly increased the fruit retention percentage and bunch weight compared to the untreated ones. Yeast application was more effective compared with boron or zinc application. -       Spraying either yeast, boron or zinc at any studied concentration was accompanied with improving fruit quality in terms of significant increase in fruit weight, total soluble solids and sugar contents. No significant differences were detected between spraying with yeast at 250 or 500 ppm, 500 or 1000 ppm zinc, as well as, boron at 1000 or 2000 ppm. Moreover, active dry yeast spraying revealed the highest improvement in palm yield and fruit quality. However, it can be concluded that spraying either boric acid, zinc sulphate or active dry yeast twice after fruit set and one month later increased the palm yield and improved the fruit quality of Zaghloul date palm. Meanwhile, using dry yeast as more effective than both boric acid and zinc sulphate.