الفهرس 
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Abstract
Three field expriments were carried out at the Research
and Experimental Station of the Faculty of Agriculture at
MoshtohoT, Zagazig University, Kalubia, Egypt, during 1981,
1982 and 1983 seasons. The intention was to study the effect
of delaying sowing dates and the absence of some irrigations
during the different stages of plant growth on yield, earliness
and fiber and yarn properties .
A split-plot design with four replications was used.
Th e t h ree sow i n g d ate 5 i _e ., Mar chI!!..!..,ApT’ill st. and ”1ay 1s t.
were applied in the main plots . The sub-plots were devoted to
8 irrigation treatments as follows
B L- Control: It is worth mentioning that the control treatments
were 10,9 and 8 irrigations, for the first, the
second and .the third’ planting dates, respectively-
B2- Without the first irrigation .
B3- Without an irrigation at the beginning of flowering stage.
B4- Without an irrigation at the beginning of fruiting stage.
B5- Without the first irrigation and an irrigation at the
beginning of flowering stage.
B6- Without the first irrigation and an irrigation at the
beginning .d fruiting stage.
B7- Without an irrigation at the beginning of flowering stage
and an irrigation at the beginning of fruiting stage
B8- Without the first irrigation~ an irrigation at the beginning
of flowering stage and an irrigation at the beginning
of fruiting stage .
It is rather interesting to note that the first irrigation
was given after 30 days from sowing date. The other irrigations
were applied at IS-day intervals. Other cultural practices
were done according to the system usually followed in
Kalubia district. The sub-plot area waS 10.5 m
2
.( 1/400 fed.)
with 5 rows; each row was 3.5 m. long~ 60 em. apart and hills
were spaced at ZO em. apart. The plants were thinned to two
plants per hill after 45 days from sowing time . ~alcium super
phosphate ( 16% PZOS ) at a rate of 24 kg. P205 per feddan was
applied immediatly before the first irrigation . The nitrogen
fertilizer ( ammonium nitrat~ 33.5 X) was applied at a rate of
50 kg. N/fed. just”before the second irrigation. The Egyptian
” .
long staple variety Giza 75 ( £.barbadense ) was used as a
material in the present study . This variety was derived from
a cr0&S between the two Egyptian varieties Giza 67 and Giza 69.
Giza 75 is a high yielding variety baving higher yarn strength
as compared withit8”parent~ . It is also characterized by
high lint percentage which is slightly lower than Giza 69
variety. The plots were picked twice. the first picking was
done 40 days after the first boll opening and the second one
was done 20 days. after the first picking .
Studied Characters :
The growth attribu~es~ earliness, yield~ yield components
and fiber and yarn properties, were studied in the present
investigation. The results, obtained could be summarized as
follows :
(A) Growth Characters
1. There was a tendency of increase in germination i.
as a result of delayi~g sowing date. This trend was
the same in all the three seasons involved in the
s t u dy •
2. The plant height tended to decrease significantly
when the sowing date was delayed in all the three
seasons under study. It was also found that there
was a tendency of decrease in plant height as a
result of reducing the numbe~ of irrigations, given
to the plants •
3. The delayed date of sowing resulted in decreasing
the number of fruiting branches per plant. This
trend could be seen during the three seasons. The
irrigation treatments showed an insignificant effect
on the number of fruiting branches per plant
4. ~he number of vegetat~ve branches per plant tended
to decrease significan~ly when the planting date
was delayed in two seasons out of three . The effect
of irrigation treatments on the number of vegetative
branches per plant was not significant in all seasons.
(B) Earliness:.
1. The delaying in planting date caused a marked reduction
in the number of days to the first flower appearance
and th~ first boll opening . There was a general
trend of decrease in the days to the first flower
and the first boll opening whenever the number of
irrigations decreased .
2. The height of first fruiting branch tended to increase
significantly as the planting date was delayed . The
decrease in the number of irrigations did not affect
significantly the height of first fruiting branch.
(C) Yield and Yield Components :
1. The number of open bolls per plant tended to decrease
materially when the plants were grown late in April or
in May. The absence of the first irrigation did not
significantly affect the number of open bolls per
plant • However, the absence of an irrigation either
before the flowering stage or the fruiting stage
res~lted in decreasing the number of open bolls per
plant . whereas ~he absence o£ two irrigation$
obviously reduced this character . In fact the
lowest number of open bolls per plant. was obtained
when three irrigations were absent .
2. The earlier sowings resulted in a higher boll
weight • It was clear that the absence of the first
irrigation did not result in a significant differences
among the averages of boll weight as compared
with the control. However. whe~ an irrigation was
not given eithet before flowering stage or fruiting
stage, .the boll weight si gnifieant 1y dec rea sed . The
absence of two irrigations, distinctly reduced the
boll weight. However, the lowest boll weight was
observed when th~ee irrigations, were not given.
3. The plant stand evidently increased when the seeds
were sown late. Irrigstion treatments did not reveal
any significan~ effect on plant stand
4. SeeJ cotton yield per plant was substant~ally reduced
as a result of late planting. Irrigation treatments
proved to have a pronounced effect on seed cotton
yield per plant a8 indicated by the fact that the
absence of anyone irrigation tended to significantly
decrease seed catton iield per plant compared with
the control . This tendency was more evident as the
number of absent irrigations was increased .
The latesow~ng dates tended to decrease the seed
inde~. It is clear, however that the plants grown
in April and May did not differ significantly regarding
their seed index, but they w~re generally of
lower seed index values than those grown earlier in
March. When the first irrigation was not given the
seed index was not significantly affected .
On .th. other hand, the absence of an irrigation
either before the flowering stage Of th~ fruiting
stage slightly reduced the seed index. This pattern
was true when two or three irrigations were not
given. ’However. the differences between the irri~
gation treatments were generally small .
6. ’The lint percentage was found to be significantly
reduced wh~n the sowin~ date was delayed . Irrigation
treatments had no significant influence upon
the lint percentage
7. There was no sign~ficant difference between the
averages of seed cotton yield/feddan when the plants
were grown· in March or April
On the co~trary. a ~arked reduction Ln yield was
registered when the plants were grown late in May.
The same pattern was true regarding lint yield per
feddan. The absence of anyone irrigation resulted
in a significant decrease in both seed cotton yield
and lint yield per feddan . However. when two irrigations
were absent this tendency of dec~ease was
more pron6unced • In fact. the lowest seed cotton
yield and lint y~eld per feddan were obtained when
three irTigations were not given .
8. There was no significant differences between the
averages of seed yield per feddan when the plants
were grown in March or April. However. the planting
date did not appear to have any significant effect
on oil percentage • whereas the oil yield per feddan
significantly increased when the plants were grown
in April as compared with those grown in March.
On the other hand when the planting date was
delayed till Maya quite size.able reduction in seed
yield and oil yield per feddan was found . Irrigation
treatments, had no evident. effect on oil percentage.
When an irrigation was not given, a significant decrease
in seed yield per feddan was found. However.
the magnitude of reduction in seed yield was dependent
on the time at which that irrigation was not
given. It is obvious that the tendency of decrease in
seed yield was clearer as the number of absent irrigations
increased .
In regard to the effect of irrigation treatments
on oil yield per feddan, it was found that when the
first irrigation was not given, no significant
difference 1n oil yield was observed, while the
absence of an irrigation either before flowering
stage or fruiting stage caused a significant reduction
in oil yield. ltis clear, however that the
oil yield tended to decrease progressively as the
number o~ absent irrigations increased. This. was
indicated by the lowest oil yield obtai~ed when
three irrigations were not given .
(D) Fiber and Yarn Properties :
1. Fiber 2.5% S.L., 50% S.L. and length uniformity
ratio, were not found to be significantly affected
by planting date. Irrigation treatments did not reveal
any dlstincteffect upon fiber length characteristics.
2. Fiber tensile properties i.e. tenacity, elongation ,
toughness and stiffness did not .appear tQ be significantly
influenced by planting date. Also irrigation
treatments proved to have an insignificant effect on
fiber tensile properties .
3. Planting date exhibited insignificant effects on both
percent reflectance ( Rd % ) and degree of yellowness
( + b ) in 1981 and 1982 seasons.. Howev~r, in 1983
season, it was found that percent reflectance tended
to decrea~e significantly when planting date was
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delayed. The reversed pattern was true regarding
. -’;”’, the degree of yellowness ( +b ). ~here i~ was
observed that ( +b ) values significantly increased
with delaying planting date in 1982 season • Irrigation
treatments had no significant effect on
cotton colour measurements .
4. There waB a general tendency of decrease in Micronaire
reading in the two seasons 1981 and 1982 as
planting date was delayed. However, planting date
showed an insignificant effect on Micronaire’reading
in the third season 1983. Irrigation treatments did
not show any significant influence upon Micronaire
read ing .
5. Lint cotton grade was not found to be significantly
affected by planting date during two seasons .However
in 1982’ season, cotton grade declined gradually when
the sowing date was delayed . Irrigation treatments
did not exhibit any significant effect on lint cotton
grade .
6. Planting date had no significant effect on yarn
strength expressed in terms of lea product in two
seasons. However, during 1982 season, yarn strength
..... ’
tended to diminish progressively when the planting
date was delayed. Irrig~tion treatments. did·not show
”,:’. any significant effect on yarn strength except in
1982 season.
7. Yarn appearance grade was not significantly affected
by planting date during 1981 and 1983 seasons . The
reversed pattern was true in 1982 season. but there
was no definite trend related to planting date . In
fact the highest yarn appearance grade was obtained
when the plants were grown in April during that
season .
”~’,.
Irrigation treatments did not show any significant
effect on yarn appearance grade .