الفهرس 
Effect of deficit irrigation (DI)Only 14 pages are availabe for public view
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Abstract
Sameh Mohamed Mohamed El-Sawy: Rationalization of Water
Consumption of Tomato Plants Grown Under Sandy Soil Conditions.
Unpublished Ph. D. Thesis, Department of Horticulture, Faculty of
Agriculture, Ain Shams University, 2016.
Field experiment was carried out during the two growing seasons of
2012/2013 and 2013/2014, in a private farm at Bani Salama region, ElGiza Governorate, Egypt, in order to investigate the effect of deficit
irrigation (DI) treatments (100% (control), 85%, 70% and 55% of ET
o
(Reference evapotranspiration)), irrigation systems (surface drip irrigation
(SDI) and subsurface drip irrigation (SSDI) (with 20cm soil depth)) and
foliar application of glycine betaine concentrations (GB) (at 0, 5, 10 and
20 mM/l, applied after 2 and 6 weeks from transplanting date), on
vegetative growth, fruit yield and quality of tomato plants (Marwa hybrid)
grown under sandy soil conditions.
Results indicated that DI treatments (85%, 70% and 55% of ET
o
)
significantly decreased the vegetative growth (plant length, number of
leaves per plant, total leaves area per plant and fresh and dry weights of
tomato leaves per plant), flowering (number of flowers, number of
clusters per plant) and fruit yield (number of fruits per plant and total
marketable yield) parameters for tomato plants. Where, the highest
significant values were obtained by the full irrigation treatment 100% ET
o
(control) and the lowest values were noticed with 55% ET
o
treatment.
Similarly, photosynthetic pigments (chlorophyll a, chlorophyll b and
carotenoids), leaf relative water content (LRWC), membrane stability
index (MSI), leaves mineral content parameters were reduced with
decreasing irrigation water levels. In contrast, there were positive effects
on proline content of tomato leaf and some fruit quality characteristics
(TSS, total sugars, ascorbic acid content and titratable acidity) for
tomatoes, as well as on irrigation water use efficiency (IWUE).
Subsurface drip irrigation system produced the highest significant
values for vegetative growth, flowering and fruit yield and quality
parameters, compared to SDI system, as well as the highest significant
values for LRWC, MSI and IWUE were observed with SSDI system in
the both tested seasons. Results showed that when DI treatments (85%,
70% and 55% ET
o
) decreased total marketable yield by (16.05%, 26.73%
and 46.61%) and (16.01%, 27.29% and 46.96%), while SSDI system
positively increased it by (4.31% and 4.85% and 4.38%) and (2.49%, and
5.54% and 5.80%), in the first and second seasons, respectively.
Foliar application of GB at 10 mM/l ameliorated the negative effects
of water stress and produced the highest significant values of vegetative
growth, flowering parameters, photosynthetic pigments, LRWC and MSI
in the both studied seasons. While, there were no significant differences
were realized among the GB treatments on the most of fruit quality
characteristics. Results reported that, When DI treatments (85%, 70% and
55% ET
o
) decreased total marketable yield by (14.38%, 25.08% and
48.77%) and (14.23%, 24.78% and 47.03%), the foliar application of
glycine betaine (at 10 mM/l) increased it by (10.95%, 10.11% and
22.85%) and (12.92%, 9.26% and 20.74%), in the first and second
seasons, respectively.
The interaction among DI treatments, irrigation systems (IS) and
foliar application of GB illustrated that tomato plants were irrigated by
100% and 85% ET
o
with SSDI system and foliar application of GB at 10
mM/l had the highest significant values for vegetative growth, flowering
and fruit yield and quality of tomato plants under open field conditions. It
was also concluded that the vegetative growth and fruit yield as well as
fruit quality of tomato plants which grown under DI conditions, can be
enhanced by using SSDI system and foliar application of GB at 10 mM/l.
Key words: Tomato, Deficit irrigation, Irrigation systems, Subsurface
drip irrigation, Glycine betaine, Yield, Fruit quality, IWUE,
LRWC, MSI.