الفهرس 
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Abstract
SUMMARY
STUDY OF YIElD POTENTIAL CR SOME NiEAT VARIETIES AS
AFFIIJTED In!’ N FERTI L IZATI ON.
Experiments for studying the effect of nitrogen
application levels on wheat yield and its components were
carried out at Bahteem Agricultural Research Station during
the two sue ce ss ive sea son s 19851 1!J8 6, and 19 86I 1987 .
The selected old varieties were:
1- Mabrouk; 2- Tosson; 3- Giza 155; 4- ,Giza 156.
Whereas, the new cultivars were 5- Giza 157; 6- Sakha 8;
7- Sakha 61; and 8- Sakha 69. The applied nitrogen levels
were zero, 2’5, 50 and 75 kg NI faddan in the form urea(46 ~).
Split plot design was used in these experiments with four
replications. The main plots were assigned for the applied
nitrogen levels and the sub plots were devoted for the tested
varieties.
R-e-s-u-l-t-s---c-o-u-l-d---b-e--s-u-n-m-a-ri-z-e-d----a-s--f-o~l-l-o-w-s-:
1- The new tested wheat varieties were superior to
the old ones in flag leaf area. The new varieties showed
higher response to ni trogen app Iication compared wi th the
old ones in respect of flag leaf area. Whereas the applied
nitrogen levels did not exhibit significant effect on this
character. The interaction effect of N x varieties on the
flag leaf area was not significant.
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2- Number of duys to hetiding of whetit pltints wus not
significantly affected by the tipplied nitrogen levels in
both setisons. However, the new varieties were more earlie
r in h ea din gas comp are d wit h the 0 I d va r ie tie s . 1n
the first growing seasaIlJ the effect of N application in
deltlying heading wus nwre appurent with the new varieties
camp a red wit h the a Idon e s . Eve nth 0 ugh the in tera c ti 0 n e ffect
of N x vlirieties WtiS not significtlnt, the latest heliding
date WliS lifter 93.25 dliys for Tosson variety supplied
with 5U kg N/ fuddun.
3- l\ltiturity of whelil plunts WliS significuntly deltiyed
by increasing nitrogen levels only in the first season
uf experimination. The effect of nitrogen was only evident
at the level of 75 kg N/ faddun, where number of days from
pllil1ting to maturity wus increased by ubout ten days comp8-
red with zero, 25 und 5U kg N/ faddan levels. In the first
season it was not i c,ed that the new wheat va r t e t i e s were, in
general, earlier in maturity than the old varieties. The
earliest v a r ie t y wa s Sa khu 61 lind the latest one WIiS Mab rouk ,
with u difference of 4.59 days.
. No
significtint interaction effect of N x varieties was obtained
on nmturity dutes. Averaged over all the tested varieties,
it was noticed that maturity in the second season wus delayed
by 12.67 days compared with the first season •
._ ..... _--- --- -- --- -_ .. - -- --- --_ •._-----
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4- Wheat plant height was not significantly affected
by nitrogen lelw~is under the circwnstances of this experiment.
The four old varieties were s lgn i Licun t Iy t al Iar
t hun the four new va r lt ie s . The tallest variety was l\tibrouk
with an average plant height of l27.5U em, and the shortest
variety was Sakha 69 with an average plant height of 103.5
em. It could be concluded that the newly introduced wheat
varieties were shorter compared with the old ones. No sig-
Ilificant interaction effect for nitrogen x varieties on the
plant height was obtained in the two Seasons.
5- Spike length was not significantly affected by
the applied nitrogen levels. There were a significant differences.
in spike lengths among the tested varieties. Whereas,
the interaction effect of N x vl:l.rietieson this character
was not significl:l.nt.
6- Numbe~ of spikelets per spike was not significantly
af f’ec t ed by nitrogen levels. There were significant differences
iln the number of spikelets per spike among the tested
var ie t ie s in the two growing seasons. In the first season,
Giza 155; Giza 157, and Sakha 69 were significantly superior
in number of spikeletsl spike compared with Mabrouk; Tosson;
Giza 156; andSakha 61. The interaction effect between nitrogen
levels and varieties on number of spikelets per spike
was not significant in both of the growing seasons.
---------- -- ---- --------- ------ --- -------,.~---------
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in u descending order as Sakha 61, Sakha 69, Sakha 8 then
Giza 157. Significant difference was only found between
Sakha 61 and Giza 157 in this group. It could be concluded
that varieties differed in their potentiality to produce
fertile tillers bearing spikes, and the old varieties
seemed to be superior in this respect. The interaction effect
of nitrogen and varieties was not significant on the
number of spikes per square meter.
10- Nitrogen application had no significant effect
on lOOO-grain weight in both seasons. It could be concluded
that the tested varieties differed markedly in 1000-
grain weight due to their great differences in their genetic
make up and to their grain development behaviour. No
significant interuction effect was found for N x varieties
on lUOU- grain weight in both seasons.
11- Whea~ grain yield was affected with the applied
nitrogen in the two grown seasons. The application of 25,
50 and 75 kg N/ faddun increused tne grain yield by 41, 2,!!
and 39 %, respectively over the control in the first season.
The corresponding increases in grain yield )n the second
season were 14, 20 and 28 %, respectively. On the average
of the eight tested varieties, the’ level of 25 kg Nt faddan
was sufficient to induce a considerable grain yield
increase.
- -,--- --_. ~-- -_.~ .. --- - ---_. _.- _.-- ._--~_.
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In the first growing season the very best grain
yielding varieties were Sakha 69 (12.45 Ardabs), followed
by Giza 157 (12.25 Ardabs) then Sakha 61 (12.05 Ardabs)
with no significant differences in between_ The previously
n~ntioned three varieties were followed by Sakha 8
(10.85 Ardabs), then Giza 155 (10.05 Ar dabs ) without significant
difference. Meanwhile, the latter two varieties
were significantly superior than Mabrouk (9.10 Ardabs) ,
followed by Giza 156 (8.35 Ardabs), then Tosson. The two
latter varieties were the worst inferior varieties
among the other tested ones with a significant difference
in yield between the first and the thierd variety.
It could be gcnerlilly concluded that the new varieties
out yielded the old ones with one exceptional case for
Giza 155 which was one of the best varieties in the second
season. Meanwhile Sakha 69 and Sakha 61 ranked on first
position in the first and second seasons, respectively.
Also Tosson was the least productive variety in both seasons.
The present results indicate clearly the superiority
of the new wheat varieties,particularly Sakha 61 over the
old ones. It was noticed that the new wheat varieties
showed higher response to nitrogen levels compared with
the old ones.
12- Straw yield of wheat was not significantly affected
by nitrogen application levels in the two seasons.
-- -- -- ----- ._-,---”- -- ._--- _.- - -_.---_. __ .--_ ..-----------~_. --_._---- ._.
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However, considerable increases were recorded in both
seasons as a result of increasing nitrogen level. It
could be concluded that straw yield was greatly affected
by varieties. In general the old varieties were Superior
to the new ones in this concern showing an OPpositive
trend to grain yield. No significant interaction effect
of nitrogen levels x varieties on straw yield was obtained
in the two seasons.
-~~--~~--~~------~--
13- Significant correlation cOfficient at 10% level
between grain yield and each of number of grains/spike and
spike yield were recorded. positive and highly significant
correlation coefficient were obtained between number of
grains/ spike and each of spike yield and spike length.
Negative and significant correlation was detected
between number of grains/spike and number of spikes/m2.