الفهرس 
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Abstract
SUMMARY .
The effect of irrigation after a depletion certain
amounts of available soil moisture content, as well as
the effect of water stress during the different stages
of growth on two corn varieties on growth, chemical
content, yield, yield components and quality of corn
grains, was studied during 1979 and 1980 seasons at the
Faculty of Agricultural Science Farm at Moshotohor Kalubia
Governorate, Egypt.
Four field experiments were carried out. Twoexperiments
were performed in 1979 and 1980 seasons to study
the effect of irrigation after depletion certain amounts
of available soil moisture (60%, 8~, 100%, lO<m for one
week, 100%for two weeks and 100%for three weeks). Every
experiment included six treatments of irrigation regimes,
the treatments in the two seasons were arranged in a
complete randomize block design in five replications.
corn cultivar D.C. 19 was sown on 23 and 20 Kay 1979 and
1980 respectively.
Other two experiments were performed in 1979 and
1980 seasons to study the effect of water stress during
the different stages of growth on two corn varieties.
Every experiment included 8 treatments which were the
combination of two corn varieties (Double Cross 19 and
American Early) and four water stress treatments. The
water stress treatments were as follows:
1. Irrigation after depletion 50% of available soil
moisture during all growth season.
2. Irrigation after depletion 5~ of available soil
moisture during all growth season, with the exception
of vegetative stage in which plants exposed to water
stress.
3. Irrigation after depletion 50% of available soil moisture
during all growth season, with the except ion of
flowering stage in which plants exposed to water stresS.
4. Irrigation after deplet ion 50% of available soil moisture
with the exoeption of maturity stage, in which plants
exposed to water stress. Treatments were arranged in
a complete randomize block design in five replications.
Qharaoters studied:
!.. Growth:
1. Time of tasseling, 2. Time of silking, 3. Plant
height, in cen~imeters) 4. Percentage of lodged plants,
5. Percentage of barren plants, 6. Percentage of green
plants, 7. Bar position, in centimeter, 8. stem diameter
2
and 9. 4~ leaf area, in ems ~
B. Yield:
1. Number.of ears per plant, 2. 11arlength, in cms.
3. Ear diameter, in cms~ 4. Ear weight in gm, 5. Ear
grain weight in gm,. 6e Numberof rows per ear,
7•. Number of grains per row, 8e Shelling percentage,
9. Grain yield per plant in gm, 100 Ear yield kgs per
faddan, 11. Grain yield kga per faddan, 12 .•”eight of
100 grain, in gm, and 13 straw y:le1.d kgs/faddano
c~ f.o..ohnologicel 2!”Opert1ea~
1. Hectolitter weight, 2. Embryo percentage to total
grain weight, ). Bndosperm percentage to total grain weight,
4. Testa percentage to total grain weight, 5. 011 percentage,
6. crude protein percentage, end 7. B’tIarch peroentage.
d. Chemical constituent~:
1. TotaI, free and bound water content in 4~ leaf,
2~ Free sugars content in 4-th leaf, ). Total chlorophyll
and carotenoids contents in 4-th leaf, and 4. Amino acids contents in 4-th leafThe following are the most important reeul ts:
Effect of irrigation after depletion certain amounts of
available solI moisture:
I. Growth:
1. Increasing depletion of available soil moisture
affected significantly all growth characters in 1979 and
1980 seasons.