الفهرس 
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Abstract
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SUMMARY
Lodging is considered as the main problem in growing wheat
cultivar Giza 155 in Egypt especially when using high seeding rates
and heavily applied nitrogen fertilizers.
The present study was carried out in the two successive growing
seasons (1988/1989) to identify the effect of cycocel on the growth,
lodging and yield of wheat under different rates of seeding and nitrogen
levels.
Two experiments were carried out at the Research and Experiment
Station of the Faculty of Agriculture, at, Moshtohor, in 1988
and 1989 seasons.
Each experiment contained 18 treatments which were the
combinations of three sowing rates (60, 75 and 90 kg seed/fed.), two
CCC treatments (0.92 litre/fed. or without spraying) and three nitrogen
levels (45, 60 and 75 kg/Ied.),
These combinations were randomly distributed according to
split-split plot design with four replications.
Results could be summarized as follows :
I. Effect of seeding rates :
1. Sowing rates significantly affected plant height on the first
season, where the tallest plants were produced from plants
sown by 60 kg seed/fed.
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2. Number of tillers/m2 and number of spikes/m2 were not
significantly affected by the applied sowing rates. However,
increasing sowing rates from 60 to 90 kg seed/fed. caused
insignificant increase in both characters.
3. Sowing rates did not significantly affect lodging percentage.
The lowest percentage was found in plants sown by 60 kg
seed/fed.
4. Spike length and weight, number of grains/spike and 1000-grain
weight were not significantly affected by sowing rates, except
spike weight in the first season. These characters decreased
with the increase in sowing rates up to 90 kg seed/fed.
5. Grain yield and straw yield decreased with the increase in
sowing rates up to 90 kg seed/fed. in both seasons. This reduction
was not enough to reach the level of significance. However,
the highest grain and straw yield were obtained from plants
sown by 60 kg seed/fed.
6. Harvest index was slightly affected by sowing rates.
II. Effect of CCC :
1. Plant height and lodging percentage decreased with cycocel
application in wheat plants.
2. Number of tillers/ m2, number of spikes/ m2 and lOOO-grain
weight increased with the application of cycocel- These increases
were not significant, except number of spikes/m2•
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3. Cycocel application did not affect weight of spike whereas,
number of grains/spike was significantly increased in the
first season only.
4. Cycocel application to wheat plants increased grain yield
by 47.8 and 69.9 kg/fed. in both seasons. But straw yield
decreased by CCC application by 0.3 and 0.6 ton/fed. in
the two seasons respectively.
5. Protein percentage and harvest index were not affected by
CCC application.
III. Effect of nitrogen fertilizer :
1. Plant height and number of tillers/m2 increased by increasing
nitrogen fertilizer from 45 to 75 kg N/fed.
2. Lodging percentage and spikes number/m2 increased by increasing
nitrogen fertilizer up to 75 kg N/fed. without significant
differences, except lodging percentage in the first season.
3. Spike length increased with the increase in nitrogen application
up to 75 kg N/fed.. This increase was significant only in the
second season.
4. Spike weight, number of grains/spike and weight of 1000-grain
were not affected by nitrogen application, except the later
two characters where number of grains/spike and weight
of 1000-grains were significantly decreased only in the first
season.
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5. Grain yield of wheat was significantly increased by increasing
nitrogen fertilizer up to 60 kg N/fed.. Further increase of
nitrogen application caused reduction in grain yield. But,
straw yield increased by increasing nitrogen application up
to 75 kg N/fed. by 0.25 and 0.40 ton/fed. in both seasons.
However these increases were not significant.
6. Protein percentage in the wheat grains and harvest index
were not affected by nitrogen level, except the first character
in the second season.
IV. Effect of interaction :
1. Plant height was significantly affected by the interaction
between seeding rates, CCC and nitrogen fertilizer in the
first season only. The highest value of plant height was obtained
by using 60 kg seed/fed., 60 kg N/fed. without the application
of CCC while, the lowest value was given by the application
of 90 kg seed/fed-. 60 kg N/fed. + 0.92 L/fed. of CCC.
2. Number of tillers/m2 was significantly affected by. the interaction
between CCC and nitrogen fertilizer in the first season
as well as that of sowing rates X cycocel X nitrogen levels
in the second one. The highest number of tillers/m
2
was
obtained from plants sown by 90 kg seed/fed. and applied
with 75 kg N/fed. and 0.92 L/fed. of CCC.
3. Concerning anatomical studies diameter of whole stem decreased
by the application of 75 kg N/fed. + CCC whereas stem thickness
increased with 45 kg N/fed. + CCC and 75 kg N/fed.
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Led to an increase in stem thickness.
The hickness of the external fibrouS layer increased with
the application of high level of nitrogen + eee.
Thickness of ground parenchyma also, increased with
the high level of N + CCC than the other treatments
which indicate that c:ycocel increased the thickness of ground
parenchyma in plants given 45 or 75 kg N/fed.
The hollow pith diameter decreased with the application
of high level of N + CCC than the other treatments.
The high level of nitrogen fertilized + CCC increased
the thickness of the cellular part, even the diameter
of the stem morphologecally decreased.
The thickness of the epidermis decreased in all treatments
especially the high level of nitrogen.
The number of the external fibrous and parenchyma layer
increased with the high nitrogen level + CCC.
All treatments exceeded the control (45 kg N without
CCC) in the number of external vascular bundles, whereas,
the highest number of the internal was obtained by the
high level of nitrogen + CCC.
All the treatments exceeded the control (45 kg N/fed.)
in the total number of vascular bundles especially the
high level of nitrogen + CCC.
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The diameter and width of layer bundles behaved differently,
the high level N + CCC led to excess in the diameter
of the bundle and reduction in the width of the bundle,
and increased the number of fibrous cell sheathing the
bundle.
The diameter of meta-xylem vessels decreased with the
application of CCC even with high or low nitrogen level.
Increasing nitrogen level from 45 to 75 kg N/fed. with
application of CCC increased liginin thickness.
4. Each of lodging percentage, number of spikes, number of
grains/spike, IOOO-grain weight and grain yield was significantly
affected by the interaction between sowing rates, CCC and
nitrogen levels. The application of 60 kg N/fed. for plants
sown by 60 kg seed/fed. and sprayed with 0.92 L/fed. of
CCC produced the highest grain yield of wheat.
5. Straw yield was significantly affected by the interaction
between nitrogen fertilizer, and cycocel as well as seeding
rate X nitrogen X cycocel only in the first season. For the
highest straw yield production of wheat plants could be sown
by 90 kg seed, fertilized with 60 kg N and sprayed with 0.92
L/fed. of CCC as a foliar application.
6. The highest protein percentage in grains was noticed in plants
sown with 60 kg seed/fed. and fertilized with 7’5 kg N/fed.
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