الفهرس 
Effect of genotypesOnly 14 pages are availabe for public view
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Abstract
The purpose of this study is evaluation of twelve white hybrids of maize under different levels of plant densities and N fertilizations. An experiment was conducted for this purpose in the Agricultural Faculty farm of Kafi El-Sheikh in a design of split-split plot design with three replications where the twelve white varieties were designated to three groups according to their genetic constitutions as follows: 1- Single crosses which include S.C.lO, S.C.103and S.C. 122, S.C. 124 and S.C. 129. 2- Three- way crosses which consist of T.W.C.47, T.W.C. 3 10, T.W.C. 320 and T.W.C. 321. 3- Double crosses and open pollinated varieties representing by Taba, G.- 2 and Giza Balady. These hybrids were evaluated under three plant density levels i.e. -? (I (Dl), 35 (D2), 30 (D3) thousand plantdfad. which were arranged in the main plot of the design and these plant densities were combined with three nitrogen levels (N) i.e. 120 (NI), 140 (N2) and 160 (N3) kg Nifad. which was used as split plot and fmally the varieties were placed in the split-split plots. The experiment was conducted in 1995 season and repeated in 1996 season, the planting date of both seasons were 20 May (1 995) and 25 May (1996). All the recommended agricultural practices were used during the growing season as it is used normally in maize production. During and after harvesting period and the following observations and readings of the data were calculated as follows : 1- Flowering : number of days fiom sowing to 50% tasselling and 50% of silking. 2- Plant height (cm): by measuring the heights of ten guarded plants in each smallest plot from the ground survice to the tassel. 3- Ear height (cm): also by measuring the ear height fiom ground service of to the upper ear in the same ten guarded plants mentioned above. 4- Grain yield: by calculating the mean yield (kg) for 10, 12 and 15 guarded plants in each smallest plot for 20 (Dl), 25 (4a)nd 30 (D3) thousand plants/fad., respectively, according to the plot size; then number of ears were accounted, dried, shelled and the grain yields were estimated as grain yield/plot and adjusted on the basis of 15.5% moisture content, transformed latter to ardablfaddan. 5- Number of earslplant: the number of ears harvested fiom 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 estimated as follows: a- Ear length (cm): estimated by measuring the length of random five ears chosen from each smallest plots then got the mean length of ear. b- Ear diameter (cm): estimated by measuring the diameter of five ears chosen at random fi-om each smallest plot then the mean diameter of ear was calculated. c- Number of rowslear: this trait was determined fiom the ears which the data of length and diameter was estimated by accounting all the rows of the sample and estimating the mean number of rowslear. d- Number of kernelslrow: this trait was determined by accounting the number of kernels of five ears from each smallest plot and divided by the mean number of rows in the chosen ears to get mean number of kernelslrow. e- 100-kernels wei&t: estimated by taking randomly samples of grains, each of 100-kernels weighted and then estimating the mean 100-kernels weight.