الفهرس 
Effect of genotypesOnly 14 pages are availabe for public view
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Abstract
The purpose of this study is evaluation of eight yellow hybrids of maize under different levels of plant densities and N fertilization. An experiment was conducted for this purpose in the Agriculture Faculty farm of Kafr El-Sheikh in a design of split-split plot design with three replications where the eight yellow varieties were designated to three groups due to their productivity as follows: 1 - Single crosses (highly productive) which include S.C. 152, S.C. 1 GO and S.C. 161. 2- The second rank of productivity which includes T.W.C.352 and PSCO38. 3- The moderate productive hybrids which consist of Amoun, Dahab and I-ladia 70. These hybrids were evaluated under four plant density levels i.e. 20 (D), 25 (Dz), 30 (D3) and 35 (D4) thousand plant/fad. which were placed in the main plot of the design and these plant densities were combined with three nitrogen levels (N) i.e. 100 (N,), 130 (Nz) and 160 (N3) unitsifad. which was used as split plot in the design whereas the varieties were placed in the split-split plots. The experiment was conducted in 1995 season and repeated in 1996 season, the planting data of both seasons were 25 May (1995) and 29 May (1 996). Summary All the . recoinmended agriculture practices were used during the growth season as it is used normally in maize production. During the growing season till harvesting period and after harvesting the following observations and readings of the data was calculated as: 1- Flowerinrr, : number of days from planting date to 50% tasselling and 50% sillting . 2- Plant height (cm): by measuring the heights of ten guarded plants in each smallest from the growing to the tasselled. 3- Ear height (cm): also by measuring the height of the upper ear from the grown service on the same ten guarded plants mentioned above. 4- Grain yield: by calculating the mean yield (kg) for 10, 12, 15 and 17 guarded plants in each sinallest plot for 20 (Dl), 25 (D2), 30 (D3) and 35 (D4) thousand Pl./fad. respectively, which represented the plot size in this case then number of ears were accounted, dried, shelled and the grain yields were estimated as grain yieldlplot and adjusted on the basis of 15.5% moisture where later transformed on the basis of ard./fad. 5- Number of ears/plant: the number of ears harvested from each guarded plant groups were determined and then divided by the number of harvested plants to get number of earslplant. 6- characteristics of the ear were as follows: a- Ear length (cm): estimated by measuring the length of random five ears chosen from each snlallest plots then got the mean length of ear. Summary b- Ear diameter (cm): it is estimated by measuring the diameter of five ears chosen at random from each sinallest plots then the mean diameter ear was calculated. c- Number of rowslear: this trait was estimated froin the ears which the data of length and diameter was estimated by accounting all the rows of the sainple and estimating the mean number of rowslear. d- Number of lternels/row this trait was determined by accounting the number of ltesnels of five ears from each smallest plot and divided it by the mean number of rows in the chosen ears to get mean number of lternelslrow. e- 100-kernels weight: it is estimated by taking randomly samples of grains each of 100-ltemels weighted and then estimating the mean 100-kernels weight.