الفهرس 
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Abstract
The present investigation was carried out during 1995/96 and
1996/97 growing seasons at Nubaria Agriculture Research Station ,
Agriculture Research Center , at North Tahrir under calcareous soil and
surface irrigations.
The main objectives of this investigation were to evaluated eight
bread wheat cultivars (Gemmiza 1, Giza 163 , Giza 164 , Sakba 8 , sakha
69 , Giza 167 , Sahel 1 and Sids I)under twelve different agricultural
treatments ( enviromnents) included all combinations between four
planting dates (25 /10 , 10/11 ,25/11 , and 10/12 ) and three irrigation
treatments ( one irrigation, two irrigations and five irrigations) . The
eight cultivars were planted in each euvironment in randomized complete
block design with four replications .
The data were recorded on grain yield tlha , number of spikes per
aquar
e
meter ,number of kernels per spike , l000-kern
e
l weight ,
biological yield tIha, straw yield tIha, harvest index and plant height .The
data of all experiments were subjected to proper statistical analysis of
variance according to Snedecor and Cochran (1967) and the combined
analysis was conducted according to CochIan and Cox (1957) . The
stability analysis were performed by using the method ofEberbart and
Russell’s (1966) . correlation coefficients were also claculated between
all pairs the studied traits .
The results can be summarized as follows :
l-Seasons mean squares were significant for all traits except biological yield
, straw yield and harvest index.
2-The highest mean values of the studied traits were detected when wheat
plants were planted in D2 (10/11) . For the harvest index and plant height
the highest mean value were obtained when wheat was planted in D4
(10/12) .
3- Plants received five irrigations after sowing exhibited significant increase
in all the studied traits compared with those received two or one
irrigations .
4- Mean squares associated with varieties and interaction between varieties
and years were significant for all traits under study , the cultivar Sids 1
had the highest mean values for all the studied traits except harvest index .
5- The D2 (l 0/11) and five irrigations tra1ment expressed significantly
increased of number of spikes per square meter , 1000-kernel weight,
number of kernels per spike and biological yield followed by the effect of
interaction between D3 (25/11) and five irrigations treatment. However
the lowest values of these traits were detected from dfect of interaction
between D4 (late planting date 10/12) and one irrigation treatment.
6- ’The effect of interaction between planting date , irrigation trea1ments and
seasons was significant for all the studied traits except number of spikes
per square meter .
7- Sids 1 gave the highest values for grain yield t/ha , number of spikes per
square meter, number of kernels per spike and 1000-kernel weight at the
second planting date . While, the highest values for biological yield and
straw yield were recorded by Sids 1 at the first planting date .
8- Mean squares associated with interaction between cultivars and the
number of irrigation treatments were significant for all the studied traits .
Grain and biological yields were noticeably increased by increasing
irrigation numbers . The highest value of grain yield was achieved by Sids
1 followed by Sakha 8 and then by Giza -164 at five irrigations after
sowmg ,
9- Mean square associated with interaction between planting date , irrigation
treatments and wheat cultivars were significant for all the studied traits
except number of spikes per square meter in the combined analysis . The
Sids 1 expressed the highest values of grain yield tlha at the different
planting dates by one or five irrigations after sowing compared with other
cultivars . Also the straw and biological yields, the highest values were
detected by Sids I at the first planting date with five irrigations after
sowmg.
10- For stability parameters, the cultivars Giza 163 , Qemmiza I , Giza 164
, Salcha 69 and Sids I were more stable than the others under the
envirobnents study for grain yield tIha. For biological yield, the stable
performing cultivars were Giza 163 , Giza 164 and Sakha 8 . Also for
straw yield tIha the cultivar Sakha 69 exhibited more stable for this trait .
11- Based on path coefficient analysis , the most important sources of variation
in plant yield were : the direct effect of 1000-kernel weight, indirect
effect of number of kernel/spike through 1000-kernel weight and indirect
effect of number of spike 1m through 1000-kernel weight .