الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Two field experiments were conducted at the farm of the Rice
Research & Training Center (RRTC) Sakha, Kafr El-Sheikh, Egypt
during two growing seasons (1993 and 1994 seasons). The main
objective of this investigation was to study the effect of sowing dates,
N levels and some rice cultivars on some growth attributes, yield
components, yield, chemical and technological properties of rice grains
as well as simple correlation studies.
Each experiment included 27 treatments which were the
combinations of three sowing dates (May 15 th~June, 1 st and 15 th),
three levels of nitrogen (0, 96 and 144 kg Nt ha) and three rice cultivars
(Giza 171, Giza 176 and Giza 177).
Each field experiment was performed in a split-split plot design
with four replications. The area of each sub-sub plot was 10,5 m2 (3.5
x 3 m). Paddy grains were broadcasted on the well leveled sub-sub
plot.
Characters studied and data recorded:
1- Growth attributes:
After 75 days from sowing, three samples were collected in
fifteen days interval. The sample size was 1/16 m2 was taken at
random to study the following data:
1- Plant height (ern)
2- Number of tillers/ m2.
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3- Leaf area index.
4- Crop growth rate.
5- Heading date
11- Yield and its components:
1- Panicle length (em).
2- Number of filled grains/ panicle.
3- Number of unfilled grains/ panicle.
4- Weight of one thousand grain.
5- Spikelet formation efficiency.
6- Utilization efficiency.
7- Agronomic efficiency.
8- Number of panicles/ m2.
9- Grain! straw ratio.
10- Grain yield toni ha.
11- Straw yield toni ha.
111-Chemical and technological properties:
1- N-uptake in grains
2- N-uptake in straw.
3- Crude protein percentage.
4- Protein yield kg! ha.
5- Hulling percentage.
6- Milling percentage.
7- Head rice percentage.
8- Gel consistency test.
9- Amylose test.
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v~Simple correlation:
The correlation coefficients between grain yield and each of the
studied characters of yield components as well as between all studied
characters in the combined data were estimated.
The following are the most important results:
I~Growth attributes:
1- Plant height, number of tillersl m2 and leaf area index at different
growth periods and crop growth rate at 75-90 and 90-105 days
from sowing were significantly decreased by the delay in sowing
dates from May 2S th to June 15 th except plant height was longer
when sowing at early date at 75 days from sowing.
2- Sowing date on June 15 th gave earlier plants than the other dates
of sowing, whereas early planting of rice caused a delay in
heading date.
3- Nitrogen levels caused significant increases in plant height, number
of tillersl m2, leaf area index and crop growth rate at the different
growth periods and number of days to 50% heading.
4- Giza 171 cultivar significantly surpassed the other rice cultivars in
plant height and crop growth rate at the three stages of growth.
5- Giza 176 cultivar gave the maximum number of tillers! m2 and leaf
area index at 75,90 and 105 days from planting.
6- The interaction between sowing dates and N levels had significant
effects on plant height, number of tillers! m2 and leaf area index at
the three sample and heading date. Early date at May 15 th with
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application of nitrogen fertilizer at 144 kg N/ ha gave the highest
values of growth characters under study.
7- Plant height at 75 and 90 days from sowing, munber of tillers/ m2
at 75 and 105 days from sowing, leaf area index at the three
periods and heading date were significantly affected by the
interaction between sowing dates and rice cultivars. The tallest
plant and longest period to heading were obtained from Giza 171
cultivar when sowing at early date. On the other hand, Giza 176
cultivar with sowing at early date gave the maximum values of
number of tillers/ m1 and leaf area index at the different growth
periods.
8- There were significant differences for plant height and leaf area
index at 75, 90 and 105 days from sowing and number of tillersI
m1 at 75 days from sowing and heading date as influenced by the
interaction between N-Ievels and rice cultivars. Giza 171 cultivar
with applied 144 kg N/ ha gave the tallest plant and maximum leaf
area index and late heading. However, Giza 176 cultivar when
received 144 kg N! ha produced the highest number of tillers! m1.
9- Plant height and leaf area index at the three samples, number of
tillers/ m1 at 75 and 105 days from sowing and heading date were
significantly affected due to the interaction between sowing dates,
N levels and rice cultivars. Giza 171 cultivar + 144 kg N/ ha with
sowing at early date gave the tallest plant at 90 and 105 days from
sowing, maximum leaf area index at 75 and 90 days from sowing
and maximum number of days to 50 % heading. Whereas, the
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highest values for mnnber of tillers1m2 at 75 and 105 days from
sowing and leaf area index at 105 days from sowing were
produced from sowing at early with applied 144 kg NI ha to Giza
176 cultivar.
11- Yield and yield components:
1w Sowing dates had a significant effect on all studied characters of
yield and its components. Early sowing at May 15 th gave the
maximum values of panicle length, number of filled grainsl
panicle, number of unfilled grains! panicle, 1000- grain weight,
spikelet formation efficiency, utilization efficiency, agronomic
efficiency, number of paniclesl m2, grain! straw ratio, grain yield
and straw yield (ton)1 ha.
2- The above characters of yield and yield components were
significantly increased by increasing N level up to 144 kg NI ha.
3- Giza 176 cultivar surpassed significantly the other tested cultivars
for panicle length, number of filled grains! panicle, spikelets
formation efficiency, number of paniclesl m2, grain! straw ratio
and grain yield! ha.
4- Giza 177 cultivar gave the maximum 1000- grain weight, whereas
no significant difference between Giza 176 and Giza 177 cultivars
in the ratio of grain to straw.
5- Giza 17] cultivar gave the greatest straw yield yield! ha as
compared with the other cultivars under study.
6- The effect of the interaction between sowing dates and N-Ievels
were significant on panicle length, number of unfilled grainsl
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panicle, number of panicle/ m2 and grain yield (toni ha) in the
combined data. Early sowing date with application of 144 kg N/
ha gave the tallest panicle, maximum number of panicles/ m2 and
grain yield! ha, whereas, the highest number of unfilled grains!
panicle was obtained when sowing at late with 144 kg N/ ha.
7- The interaction between sowing dates and rice cultivars had a
significant effect on all characters of yield and its components
under study. Early sowing at May 15 th with Giza 176 cultivar
produced the highest values of panicle length, number of filled
grains! panicle, spikelets formation efficiency, number of panicles/
m2, grain! straw ratio and grain yield! ha. While late sowing at
June, 15th with Giza 176 cultivar gave the maximum number of
unfilled grains/ panicle. Giza 177 cultivar when sowing at earl~ or
medium date had the greatest 1000- grain weight, whereas Giza
171 cultivar when sowing at late date gave the maximum straw
yield! ha.
8- Panicle length, number of panicles! m2, grain! straw ratio, gram
and straw yields/ ha were significantly affected by the interaction
between N-levels and rice cultivars in the combined data. Giza
176 cultivar with application of 144 kg N/ ha produced the
maximum values of the above characters except straw yield! ha.
The highest straw yield (ton)/ ha was obtained by adding 144 kg
N! ha to Giza 171 cultivar.
9- There were significant differences on panicle length, grain! straw
ratio, grain and straw yield! ha due to the interaction effect
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between sowmg date, N-Ievels and rice cultivars. Giza 176
cultivar when early sowing and increasing N-Ievel up to 144 kg N/
ha produced the tallest panicle, maximum the ratio of grain to
straw and greatest grain yield! ha. On the other hand, Giza 171
when sowing at late date and applied 144 kg N/ ha gave the
highest straw yield! ha.
111-Chemical and technological properties:
1- Early sowing gave the highest significant effect on N-uptake in
grains and protein yield! ha.
2- N-uptake in straw, crude protein and amylose content were
significantly increased by delaying in sowing dates up to June
15 tho
3- Sowing rice at medium date (June 1 sf) produced the maximum
percentages of hulling, milling and head rice, whereas, gel
consistency test was not significantly affected by sowing dates.
4- N-uptake in grain and straw, protein percentage, protein yield! ha
and head rice percentage were significantly increased by
increasing N levels up to 144 kg N/ ha, whereas no significant
difference between 96 and 144 kg N/ ha in hulling percentage was
detected.
5- Milling rice, amylose content and gel consistency were not
significantly affected by increasing level of nitrogen.
6- Giza 176 cultivar surpassed significantly the other tested cultivars
in N-uptake in grains and protein yield! ha.
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7- The maximum ofN-uptake in straw was produced from Giza 171
cultivar.
8- Giza 177 cultivar gave the highest protein percentage, hulling
percentage, milling percentage and head rice percentage.
Whereas no significant differences were obtained among rice
cultivars in amylose content and gel consistency.
9- The effect of the interaction between sowing dates and N levels
were significant on N-uptake in grains, N-uptake in straw, protein
content, protein yield! ha, head rice percentage and gel
consistency. Early sowing with applied 144 kg N/ ha gave the
maximum N uptake in grains and protein yield! ha. The highest
N-uptake in straw and protein percentage were obtained from late
sowing and applied 144 kg N/ ha. On the other hand, sowing at
June 1 st when receiving 144 kg N/ ha gave the highest head rice
percentage and the lowest gel consistency.
10- N-uptake in grains, N-uptake in straw, protein percentage, protein
yield! ha, hulling percentage, milling percentage, head rice
percentage and gel consistency were significantly affected by the
interaction between sowing dates and rice cultivars. Giza 176
cultivar at early date of sowing gave the maximum N-uptake in
grams and protein yield! ha. Whereas the highest N-uptake in
straw and protein content in grains were obtained from late
sowing with Giza 171 cultivar. On the other hand, Giza 171 and
Giza 177 cultivars when sown at medium date (June I sf) gave the
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maximum percentages of hulling, milling and head rice as well as
gel consistency.
11- The interaction between N-levels and nee cultivars had a
significant effect on N-uptake in grains, N-uptake in straw, protein
percentage, protein yield! ha, hulling percentage and head rice
percentage. The highest N-uptake in grains and protein yield! ha
were obtained from Giza 176 with increasing N levels up to 144
kg N! ha. Whereas, Giza 171 cultivar with applied 144 kg N! ha
gave the maximum N-uptake in straw and protein content in
grams. However, Giza 177 cultivar with applied 144 kg N! ha
had the highest hulling and head rice percentages.
12- There were significant differences on N-uptake in grains, N-uptake
in straw, protein percentage, protein yield! ha, hulling percentage,
milling and head rice percentages as affected by the interaction
between the three factors.
v- Simple correlation coefficients:
Grain yield! ha was positive and highly significantly correlated
with each of plant height, number of tillers/ m2, LA!, heading date,
number of panicle! m2, panicle length, 1000- grain weight, number of
filled grains! panicle, spikelets formation, protein yield and the ratio of
grain to straw. However, straw yield was negative and significant
correlated with 1000- grain weight as well as the ratio of grains to
straw and number of unfilled grains! panicle.