الفهرس 
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Abstract
Two field experiments were conducted at the Research and Experim~ntal Station of the Faculty of Agriculture
at Moshtohor, Zagazig University during 1985 and 1986 seasons, to investigate suckers formation under different maize popUlations. The varieties used were
American Early, Nab El- Gamal, Giza 2, Double Cross 202 Double Cross 204, Pioneer 514, Ciba Geigy 4405 and Ciba
Geigy 4141 were grown under 12000, 15000, 20000 and 30000
plant/ faddan using a split- plot design with four replications,
where varieties were in the main plots and plant densities were in the sub-plots. Each SUb-plot was 21 m2(3.5 x 6 m) with 5 ridges. R-e-s-u~lt-s--C-o-u-l-d--B-e--Su~m~m~ar-i-z-e-d--a~s--F-ol-l-o-ws-:--~----
1- Varieties varied in number of suckers/ plant, sucker height, sucker diameter, weight of sucker ear and
grain weight of sucker ear, but with no significant differences.
D.C. 204 was superior and Ciba 4141 was the inferior in their effect on percentage of sucker bearing
ear. 2- Dry weight of stem, leaves, ears, tassels and whole plant at 60 and 75 days from planting were differed
by maize varieties without significant, except the dry weight of leaves and stems at the two samples in the
second season. D.C. 204 surpassed the other varieties in the dry weight of leaves while, A. Early produced
the highest stems dry weight, whereas, Ciba 4141 gave the lowest leaves and stem dry weights. 3- Varieties did not differ significantly in NAR,
whereas, LAI in the second sample, CGRand RGR were significant
in the second season. D.C. 204 and Giza 2 surpassed the other varieties while, A. Early and N. EIGamal
gave the lowest values in LAI. Hybrids D.C. 204 and Ciba 4405 were superior, while A. Early and N. EIGamal
were the inferior in their effect of CGR and RGR. 4- Varieties differed significantly In the time
of mid~asseling and silking. N. El- Gamal was the earliest
one while, D.C. 204 and Pioneer 514 were the latest. 5- Plant height, ear height, No. of green leaves!
plant, percentage of lodged plants, barren plants and
double- eared plants were significantly by maize varieties
in both seasons. A. Early was superior and Pioneer 514 was the inferior in plant and ear heights and lodged
plants~ while D.C. 204 surpassed the other varieties In
No. of green leaves! plant and double-eared plants. Giza 2 and D.C. 202 gave the highest values of barren
plants and Pioneer 514 gave the lowest. The differences
between varieties in stem diameter were significant in the second season. D.C. 202 was thicker and A. Early
was thiner than other varieties.
6- Maize varieties differed significantly In number
of ears/plant, ear length, ear diameter, edr weight, grain weight / ear, number of rows/ear and number of
grains/ row and per ear. D.C. 204 and Pioneer 514 were the superior and A. Early and N. El- Gamal were the inferior
in their effect of these characters.
7- Shelling percentage, weight of 100 - grain, weight of grain/ plant and yields of grains, straw and
biological were significantly affected by maize varieties.
D.C. 204 surpassed the other varieties, whereas~ the open- pollinated varieties produced the lowest values
in these characters.
8- The differences between varieties in N, P, K and protein content of the different parts of maize plants
as well as grains were not significant.
1- Plant densjty had a marked effect on percentage of suckers/ plant, perdentage of ear- bearing suckers and
sucker ear weight significantly in both seasons. All values of the previous characters decreased with increasing
number of plants/ fad. On the other hand, sucker height, sucker diameter and grain weight per sucker ear
were not significantly affected by plant density. The
differences in weight of sucker ear due to different densities
was significant in the second season. However, these characters were inversely correlated with plant
density. 2- The dry weight of leaves, stem, tassels, ears
and whole plant decreased significantly by increasing ~ant density. Low population tended to produce higher means of dry weight of plant organs than high population.
3- LAI signficantly increased, while, OGR, RGR and NAR tended to decrease significantly as plant density increased 4- Time of mid- tasseling and silking tended to increased by increasing plant density.
5- Plant densities had no marked effect on plant hiehgt and ear height.
6- Number of green leaves/ plant, double- eared
plants, stem diameter and number of ears/ plant significantly
decreased, while, number of lodged and barren plants was increased by increasing plant density.
7- Ear length, ear weight, number of grains/row and per ear, ~ight of grains/ ear, 100- grain weight
and shelling percentage were significantly decreased by
increasing plant density.
8- Ear diameter and number of rows/ ear were not significantly affected by plant density. 9- Weight of grains/ plant significantly decreased
by increasing plant density, whereas, grain yield/ faddan, straw and biological yields significantly increased by increasing plant density.
10- Nitrogen content in leave samples as well as protein content in maize grains decreased significantly
by increasing plant population density. Nevertheless, plant density had no marked effect on P and K- content
in leave samples as well as maize grains 111----E-f-fe-c-t---o-f---t-h-e--I-n-t-e-r-a-c-ti-o-n-:-
1- Dry weight of leaves and stems were significantly affected by the interaction between varieties
and plant density. D.C. 204 at 20000 plants/faddan as
well as Pioneer 514 at 15000 plant! fad. produced the maximum dry weight of leaves! plant, whereas, Ciba 4405
and 4141 produced the highest averages of dry weight of stem! plant at 60 and 75 days from planting. 2- LAI, CGR, RGR and NAR were significantly affected
by the interaction between varieties and plant density. LAI at 60 and 75 days from planting was increased
by increasing number of plants! fad. for all tested VArieties, except Giza 2 and Ciba 4405 were produced
the highest LAI at 60 days from planting obtained by 20000 plant! fad. The maximum CGR was obtained by Giza
2, Pioneer 514 and Ciba 4141 at low density (12000 plant
Ifad.). While, Giza 2, Pioneer 514 and D,C. 202 were produced the highest values of RGR at 12000 plant! fad.
With respect to NAR all tested varieties except A. Early
produced the highest values at 15000 plant! faddan. 3- Shelling percentage, weight of grains! plant
and straw and biological yields! fad. were significantly
affected by the interaction in the first season, while
grain yield! fad. was significant in the second season.
D.C. 204 produced the highest values of shelling percentage
at low density (12?00 plant! faddan), and weight of
grains! plant at low density (12000 plant! faddan). All
tested varieties were produced the highest grains yield/ fad. a t h ig h den sit Y (300 00 p lan t / fad.) except D _C . 202 and Ciba 4405. The maximum strRw and biological yieldsl
fad. were obtained by D.C. 204 at higher plant density. 4- Phosphorus and potassium content in grains were significantly affected by the in t e rae t ion between varieties
and plant densities. Ciba 4405 was produced highest value of P- content at 15000 plant / fad. in the first
season, while in the second season, D.C. 202 at higher plant density produced highest P-content. The maximum
K- content was obtained by Ciba 4141 and Pioneer 514 at 20000 plant / fad. in the first and second seasons,
respectively.