الفهرس 
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Abstract
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SUMMARY
Two field experiments were conducted at the Research
and Experiment Station of the Faculty of Agriculture,
Moshtohor, during 1981 and 1982 seasons, to
study the effect of sowing date, variety and seed rate
on the growth and yield of forage sorghum (Sorghum
bicolor (L.)Mosnch)~
The s 011 of the experiments was clay textured with a pH
value of 7.9 and an organic matter coatent of 2.51%.
Each experiment included )6 treatments which were
the combination of four sowing dates, three varieties
and three seeding rates.
Factors under study were:
1. Sowing dates: 17 !h. May, 1 at June, 16 th June and
1~!July.
2. Varietiess Pioneer (988), Sordan (79) and Sudangrass
(2) •
J. Seeding rates 10, 15 and 20 kg/fad.
The experiment was designed according to split-split
plot design in four replication. Sowing dates were arranged
at random in the main plots t the v&.l”1etytreatments were
ass~gned a~ random w1th~n the sub-plot, while the seeding
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rates were randomly distributed in the sub-sub-plots.
Results could be summarized as followss
A. Effect of sowing date: ----------------------
1. Sowing date showed significant effect on plant height
and stem diameter of sorghum at different cuts in the
two successive seasons. Plant height and stem diameter
of sorghum plRnts significantly decreased with delaying
sowing date.
2. Differences between sowing dates in number of stems/
m2, number of leaves/plant as well as LAI were significant
in the two seasons. Early sowing of May 17!!!
produced higher number of stems/m2• number of leaves/
plant and LAI as compared with other dates of sowing.
On the other hand, the sowing at July 1 st gave the
highest teaf. stem ratio than the other planting dates.
3. Dry weight of plant organs was significantly affected
by sowing dates in the both seasons. Drr weight of
leaves, stems and Whole plant decreased significantly
as sowing date was delayed until July 1 !!.
4. DiffereDoes between sowing date in the yields of fresh
dry as well as protein at each cut and total forage,
yield were significant In the two seasons. There was
a progressive and consistent depression in the yield
of fresh. dry and protein with delaying the sowing date.
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5. Sowing date had a significant effect on the chemical
composition of sorghum plant. Delaying
sowing date increased the protein as well as HCN%
in the different plant organs of sorghum. On the
other hand, the carbohydrate% in leaves, stems
and whole plant decreased with delaying sowing date
until July IE.:!:
B. Effect of varieties I ------~-------------
1. Varieties exhibited significant effects on plant
height of sorghum plant. Sudan (2) produced
significantly higher plants than either Sor~an
(79) or ~ioneer (988) in both seasons. Whereas.
floneer (988) was significantly thicker than
those of Sordan (79) and Sudan (2).
2. Number of stems/m2, number of leaves/ plant, LAl
and leaf. stem ratio differed significantly among
genotypes at each aut in two seasons. Pioneer
(988) surpassed significantly the other varieties.
). Varieties exerted a marked effect on the dry
weight of leaves. stems and whole plant at each
cut in the two successive seasons. Pioneer (988)
produced greatest dry weight plant, whereas
Sudan (2)gave the lowest values at the two cuts
in both seasons.
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4. Varieties differed significantly in fresh yield,
dry yield and protein yield at each cut as well
as the total forage yield confirmed in both sea30ns.
Pioneer (988) surpassed Sordan (79) and Sudan (2).
5. Varieties showed significant effect on chemical composition
of sorghum plant. Pioneer (988) gave the
highest percentage of protein as well as carbohydrate
in leaves, stems and whole plant, whereas the lowest
percentage was obtained from Sudan (2). With reg~d
to HCN%, it is obvious that the HCN% of different
plant organs was greater in Sordan(79) than the other
two varieties.
c. ~!!~2!_2!_!~~~1~~_~~!~1
1. Seeding rate showed significant effect on plant height
and stem diameter of sorghum plants at each cut in the
two seasons. Increasing seed rate up to 20 kg/fad.
increased plant height of sorghum. On the other hand,
stem diameters decreased with increasing seed rate.
2. Number of atemstm2 as well as LAl. and leaf: stem ratio
increased with the increase in the seed rate up to 20 kg/
fad. in the two seasons. On the other hand, increasing
seeding ratetrom. 10 to 20 kg/fad. decreased the number
of leaves/plant.
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3. Dry weight of plant organs was significantly influenced
by seeding rates in the two seasons. Dry
weight ot leaves, stems and whole plant decreased
with increasing seeding rate.
4. Seeding rate showed significant effect on yields
of fresh, dryas well as protein at each cut and
total forage yield in the two seasons. The forage
yields incrsased with increasing seeding rate up
to the highest level (20 kg/fad.).
5. Chemical composition of sorghum plants was significantly
influenced by seeding rates. The percentage of protein
in leaves, stems and whole plant decreased with
the increase in the seed rate up to 20 kg/fad. in the
two seasons. On the other hand, increasing seeding
rate from 10 to 20 kg/fad. increased the percentage
of carbohydrate as well as HeN in the different organs
of sorghum plant.
D. Effect of’the interaction:
1. The effect of the interaction (varieties X sowing dates)
on dry weight of leaves/plant, forage fresh yield and
carbohydrate content in leaves and stems was significantly
at the 1 !!”! and 2 a~ cut only in 1982 season. The highest
values resulted from sowing Pioneer (988) on Kay 17 !~.
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while the lowest one was obtained from Sudan (2) sown
on June 16 -t-h • and July 1 -s-t.
2. The effect of the interaction (sowing date X seeding
rates) was significant on LAl in the two seasons and
on protein yield in the first seaBon. The highest
protein yield W&S obtained from higher seeding rate
(20 kg/fad.) at 2 -n-d-• cut when sorghum plant sown early
on May 17 !!!.
3. The effect of the interaction (varieties X seeding rates)
was significant on the number of stems/m2 and LA! in first
season and on stem diameter, LAl and the carbohydrate
percentage of stems in second season. In 1981 season, the
highest number of stems/m2 and LAl was obtained from
Pioneer (988) and: seeding rate 20 kg/fad. Whereas, the
highest stem diameter was obtained from Pioneer (988) with
the lowest seeding rate (10 kg/fad.).
4. The effect of the interaction (sowing dates X varieties X
seeding rates) was significant on LAl and protein yield
at the 1 !!cut only in 1981 season. The highest values
were obtained from Pioneer (988) when sown on May 17 !.h
with the highest seeding rate (20 kg/fad.