Evaluation of some rice cultivars under different water regimes and tillage systems PhD

Tanta University
Faculty of Agriculture
Agronomy Department
EVALUATION OF SOME RICE CULTIVARS
UNDER DIFFERENT WATER REGIMES AND
TILLAGE SYSTEMS
BY
Aziz Fouad El-Sayed Abu El-Ezz
B.Sc. Agric., Horticulture Dept., El-Menoufia Univ., 1998.
M.Sc. Agric., Agronomy Dept., Alexandria Univ., 2004
THESIS
Submitted in Partial Fulfillment of
the Requirements For the Degree of
DOCTOR OF PHILOSOPHY
IN
Agricultural Science
(Agronomy)
To
Agronomy Department
Tanta University
2014

Tanta University
Agronomy Department
TILLAGE SYSTEMS
BY
THESIS
IN
Agricutural Science
(Agronomy)
Examiner’s Committee: Approved
Prof. Dr. Ramadan Ali El-Refaey
Emeritus Professor of Agronomy, Agronomy Department,
Faculty of Agriculture, Tanta University.
.…………..
Prof. Dr. Mohamed Ahmed Abd El-Gawad Nassar
Professor of Agronomy, Plant Production Department, Faculty
of Agriculture (Saba Basha), Alexandria University.
.…………..
Prof. Dr. Ragab Abd El-Ghany Ebaid
Emeritus Head of Research, Field Crops Research Institute,
Agricultural Research Center.
…………..
Prof. Dr. El-Sayed Hamid El-Seidy
Professor and Head of Agronomy Department, Faculty of
Agriculture, Tanta University.
.…..............
Date: 28/12/2014

Tanta University
Agronomy Department
TILLAGE SYSTEMS
BY
THESIS
IN
Agricutural Science
(Agronomy)
Advisor’s Committee:
Prof. Dr. El-Sayed Hamid El-Seidy
Professor and Head of Agronomy Department, Faculty of Agriculture,
Tanta University.
Prof. Dr. Ragab Abd El-Ghany Ebaid
Emeritus Head of Research, Field Crops Research Institute, Agricultural
Research Center.
Prof. Dr. Taha Ahmed Shalaby
Emeritus Professor of Agronomy, Agronomy Department,Faculty of
Agriculture, Tanta University.
2014

ACKNOWLEDGEMENT
All praise and thanks to ALLAH, who gives us all the ability to
finish this work. Sincerest thanks and gratitude to Prof. Dr. El-Sayed
Hamid El-Seidy, Professor and head of Agronomy Department, Faculty of
Agriculture, Tanta University for his continuous and helpful suggestions,
and also his assistance and helpful comments on this work. I would like to
express my deepest gratitude and my Sincere thanks Prof. Dr. Ramadan
Ali El-Rfaey, Emeritus Professor of Agronomy, Agronomy Department,
Faculty of Agriculture, Tanta University for suggesting, valuable criticism
and guidance during the course of my study and for his great help in
reviewing the manuscript. Special words of thank to Prof. Dr. Ragab Abd
El-Ghany Ebaid Emeritus Head of Research, Rice Research and Training
Center, Field Crops Research Institute, Agricultural Research Center (ARC)
for his helpful suggestions, farther advice, valuable and constructive
remarks and for continuous assistance for me. Thanks duty to the spirit of
our great teacher Prof. Dr. Taha Ahmed Shalaby, (mercy of God upon
him) founder of the Faculty of Agriculture, Tanta University what we have
learned on his hands during this study. My deeply thankful to the top
management of ElWADI Export Co. for their encouraging and support to
achieve this work. My full respect and my deepest thanks to my mother, my
brothers, my wife and my lovely kids; Yasmin, Abd El-Rahman and
Yousef. Special thanks and deep appreciation to staff members of Rice
Research and Training Center, Zarzoura, Behira. Special thanks and deep
appreciation to my best friends and older brothers Eng. Mohamed Gebril
and Eng. Essam El Sabaa for their continuous support.

TABLE OF CONTENTS
CONTENTS Page
ACKNOWLEDGMENT………………..…………………………….…..
TABLE OF CONTENT…………………………………………………..
LIST OF TABLES………………………………………………………
LIST OF FIGURES …………………………………………………...
I. INTRODUCTION.......................................................................................
II. REVIEW OF LITERATURE.................................................................
A. Effect of irrigation treatments on rice growth characters, yield and its
attributes………………………………….....................................
B. Effect of tillage systems on rice growth characters, yield and its
attributes……………………………………………………………..
C. Effect of varietal differevces on rice growth characters, yield and its
attributes……………………………………………………………..
III. MATERIALS AND METHODS...........................................................
IV. RESULTS AND DISCUSSIONS...........................................................
A- Vegetative growth characters...........................................................
1- Root volume (cm3
).......................................................................
2- Root length (cm)……………………………………………….
3- Root/shoot ratio…………………………………………………
4- Number of days to heading (days).................................................
5- Plant height in (cm)......................................................................
6- Flag leaf area (cm2
).......................................................................
B- Yield and its components...................................................................
1- Number of productive tillers/m2
................................................
2- Number of filled grains/panicle...................................................
3- 1000-Grain weight in (g)..............................................................
4- Unfilled grains percentage (%)...................................................
5- Panicle weight in (g).....................................................................
6- Panicle length in (cm)................................................................
7- Biomass yield (ton/fad)........................................ …………….
8- Grain yield (ton/fad)...................................................................
9- Harvest index (%)........................................................................
C- Water relations……………………………………………………
1- Reduction percentage (%)
2- Drought sensitivity index……………………………………
3- Water use efficiency (kg/m3
)…………………………...........
D- Grain quality characters...................................................................
1- Hulling percentage (%)...................................................................
2- Milling percentage. (%).................................................................
3- Head rice percentage (%)...............................................................
V. SUMMARY...............................................................................................
VI. REFERENCES.........................................................................................
VII. ARABIC SUMMARY..............................................................................
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---

LIST OF TABLES
No. Table Title
Page
1 Origin and main characteristics of the four rice cultivars. 21
2 Effect of irrigation regimes (A), tillage systems (B), rice cultivars (C)
and their interactions on root volume (cm3
), root length (cm) and
root/shoot ratio of Egyptian hybrid 1, Giza 178, Sakha 104 and Sakha
101 rice cultivars in 2011 and 2012 seasons.
28
and their interactions on days to heading (days), plant height (cm)
and flag leaf area (cm2
) of Egyptian Hybrid 1, Giza 178, Sakha 104
and Sakha 101 rice cultivars in 2011 and 2012 seasons.
39
and their interactions on No. of productive tillers/m2
, No. of filled
grains / panicle and 1000-grain weight (g) of Egyptian hybrid 1,
Sakha 104, Sakha 101 and Giza 178 rice cultivars in 2011 and 2012
seasons.
48
and their interactions on unfilled grains %, panicle weight and
panicle length (cm) of Egyptian Hybrid 1, Giza 178, Sakha 104 and
Sakha 101 rice cultivars in 2011 and 2012 seasons.
55
and their interactions on biomass yield (t/fad.), grain yield (t/fad.)
and harvest index (%) of Egyptian Hybrid 1, Giza 178, Sakha 104
and Sakha 101 rice cultivars in 2011 and 2012 seasons.
62
and their interactions on reduction percentage (%), drought
sensitivity index and water use efficiency (WUE = (Kg./m3
)) of
Egyptian Hybrid 1, Giza 178 Sakha 104 and Sakha 101 rice cultivars
in 2011 and 2012 seasons.
73
and their interactions on hulling (%), milling (%) and head rice (%)
of Egyptian Hybrid 1, Sakha 104, Sakha 101 and Giza 178 rice
cultivars in 2011 and 2012 seasons.
82

LIST OF FIGURES
No. Table Title
Page
1 The interaction between irrigation regimes (A) and tillage
systems (B) for root volume (cm3
) in 2011 season.
29
2 The interaction between irrigation regimes (A) and rice cultivars
(C) for root volume (cm3
) in 2011 and 2012 seasons.
30
3 The interaction between tillage systems (B) and rice cultivars (C)
for root volume (cm3
) in 2011 season.
30
4 The interaction among irrigation regimes (A), tillage systems (B)
and rice cultivars (C) for root volume (cm3
) in 2011 and 1012
seasons.
31
systems (B) for root length in 2012 season.
33
(C) for root length (cm) in 2011 and 2012 seasons.
34
(C) for root/shoot ratio in 2011 and 2012 seasons.
36
8 The interaction between irrigation regimes (A) rice cultivars (C)
for days to heading in 2011 season.
40
systems (B) for plant height (cm) in 2011 and 2012 seasons.
42
(C) for plant height (cm) in 2011 and 2012 seasons.
43
systems (B) for flag leaf area (cm2
45
(C) for flag leaf area (cm2
45
(C) for No. of productive tillers/m2
in 2011 and 2012 seasons.
49
(C) for No. of filled grains / panicle in 2011 and 2012 seasons.
51
(C) for 1000-grain weight (g) in 2011 and 2012 seasons.
53
(C) for unfilled grains % in 2011 and 2012 seasons.
56
(C) for panicle weight (g) in 2011 and 2012 seasons.
58
(C) for panicle length (cm) in 2011 and 2012 seasons.
60

systems (B) for biomass yield (t/fad) in 2012 season.
63
(C) for biomass yield (t/fad.) in 2011 and 2012 seasons.
64
(C) for grain yield (ton/fad.) in 2011 and 2012 seasons.
68
systems (B) for harvest index (%) in 2011 season.
70
23 Harvest index as affected by the interaction between irrigation
regimes and rice cultivars in 2011 and 2012 seasons.
70
systems (b) for reduction percentage (%) in 2011 and 2012
seasons.
74
(C) for reduction percentage (%) in 2011 and 2012 seasons.
75
systems (B) for drought sensitivity index in 2011 season.
77
27 Drought susceptible index of Egyptian hybrid 1, Sakha 104,
Sakha 101 and Giza 178 rice cultivars as affected by irrigation
regimes in 2011 and 2012 seasons.
78
(C) for water use efficiency (WUE=kg/m3
) in 2011 and 2012
seasons.
80
(C) for hulling (%) in 2011 and 2012 seasons.
83
(C) for milling (%) in 2011 and 2012 seasons.
84
(C) for head rice (%) in 2011 and 2012 seasons.
85

1
INTRODUCTION
Rice (Oryza sativa L.) is one of the most important grains in the
world. It is not only a stable food, but also contributes to major economic
activity and a key source of income and employment for the rural population.
Rice is grown under many different conditions and production
systems, but submerged in water is the most common method used
worldwide. Rice is the only cereal crop that can grow for long periods of time
in standing water. 57% of rice is grown on irrigated land, 25% on rainfed
lowland, 10% on the uplands, 6% in deep-water, and 2% in tidal wetlands
(IRRI-2002).
Drought is one of a major abiotic stresses limiting plant production.
The worldwide water shortage and uneven distribution of rainfall makes the
improvement of drought resistance especially important. Drought resistance
includes drought escape via a short life cycle or developmental plasticity,
drought avoidance via enhanced water uptake and reduced water loss and
drought tolerance via osmotic adjustment. Early maturity has been shown to
be an important trait under lowland conditions because early flowering rice
varieties or lines can escape from the late season drought stress. However,
although early maturity is an important character, it is associated with low
yield potential and it is unlikely for early maturing cultivars to produce
higher yield than later maturing ones in absence of drought stress (Cooper et
al.,1999).
In Egypt, about 10 billion m3
of irrigation water is being used in rice
production and represents about 25% of amount of irrigation water used in
agricultural sector. The limitation of water resources and the remarkable
increase in population should force research workers to find ways for saving
some of this water without significant reduction in yield. Because of
continued population growth and economic development, the demand for
fresh water to meet industrialization and domestic needs is growing rapidly.
It is expected that, in the near future less water will be available for rice
cultivation (Tuong and Bouman 2002).

2
It is estimated that about 6000 m3
of irrigation water is needed for
each faddan of rice. Increasing demand for irrigation water recently appeared
in Egypt for the new land reclamation programs which cover an area of 3-4
million feddan of the land ranked on top of priorities envisaged by master
plan resources, these areas are located in Tushka, East Owynat, Darb El-
Arbaeen, Peace Canal and the other cultivable areas (Mahrous 2005).
Accordingly, saving of rice irrigation water is a necessary demand to cover
the water requirements of these projects. This could be achieved through
either develop new rice varieties which requires less water (short duration or
drought tolerant varieties) or through developing improved agricultural
practices for rice cultivation. One of these practices is water management by
using different tillage systems which increase the roots volume and water up-
take also, increasing irrigation intervals without any drastic effect on plant
growth and grain yield.
The objectives of this investigation were:
1. To evaluate the performance of some Egyptian rice cultivars and hybrid
under different water regimes.
2. To check the effect of tillage on water use efficiency and water saving.
3. To investigate what is the best water regime which achieves the highest
productivity with highest water use efficiency.

3
II. REVIEW OF LITERATURE
Water is the most crucial input for agricultural production. Globally,
agriculture accounts for more than 80% of all fresh water used by humans,
most of that is for crop production (Morison, et al., 2008). Tillage systems
may play a vital role in improving soil structure which in turn will result in
providing the root volume and increasing water uptake. In addition, rice
cultivars change in the response to drought stress based on its genetic
variation. These aspects will be reviewed in three partitions as follows:
1. Effect of irrigation regimes on rice growth characters, yield and
its attributes:
Awad (2001) studied the effect of three irrigation intervals (4, 8 or
12-day) on rice production. Results showed that plant height, panicle length,
number of panicles/m2
, grain and straw yields decreased significantly with
increasing irrigation intervals. However, no significant difference was found
between 4 and 8 day intervals in grain yield. 8 day treatment recorded the
highest water use efficiency (0.69 kg/m3
) and saved about 13.2% of irrigation
water compared to 4 day interval.
Bouman and Tuong (2001) stated that irrigation water is getting
scarcer and major challenges are to (i) save water, (ii) increase water
productivity and (iii) produce more rice with less water. This study analyses
the ways in which water-saving irrigation can help to meet these challenges
at the field level. The analyses are conducted using experimental data
collected mostly in central–northern India and the Philippines. Water input
can be reduced by reducing ponded water depths to soil saturation or by
alternate wetting/drying. Water savings under saturated soil conditions were
on average 23% (±14%) with yield reductions of only 6% (±6%). Yields
were reduced by 10–40% when soil water potentials in the root zone were
allowed to reach −100 to −300 mbar. In clay soil, intermittent drying may
lead to shrinkage and cracking, thereby risking increased soil water loss,
increased water requirements and decreased water productivity. Water
productivity in continuous flooded rice was typically 0.2–0.4 g grain / kg
water in India and 0.3–1.1 g grain /kg water in the Philippines. Water-saving
irrigation increases water productivity, up to a maximum of about 1.9 g grain
/kg water, but decreases yield. It therefore does not produce more rice with
less water on the same field. Field-level water productivity and yield can only

4
be increased concomitantly by improving total factor productivity or by
raising the yield potential.
Ghanem and Ebaid (2001) conducted two experiments to study the
effect of both farmyard manure and different irrigation intervals on the
productivity of rice variety Sakha 101 and the succeeding clover crop.
Irrigation intervals were continuous flooding, irrigation every 6 and 9 days.
The main results showed that, there were no significant differences in yield
and its components between continuous flooding and irrigation every 6 days.
Furthermore, 6 days intervals saved 9 % of the water used while, 9 days
intervals saved 14 % with 26 % yield reduction.
Islam (2001) studied the effect of water stress on nine rice cultivars.
He found that, water stress significantly reduced plant height, number of
panicles/m2
, panicle length, 1000-grain weight, harvest index, total dry
matter content and grain yield.
Mohamed (2001) concluded that irrigation every 3 days produced the
highest values of dry matter, number of filled grains and 1000-grain weight.
However, no significant difference was found between 3 and 6 days intervals
on crop growth rate, relative growth rate, plant height, number of panicle/hill,
unfilled grain % and grain and straw yields.
Sehly et al., (2001,a) found that, grain yield was highly affected with
prolonged irrigation for all the tested rice cultivars (Giza 176, Giza 177,
Sakha 101 and Sakha 102). The highest grain yield was obtained under 3
days followed by 6 days and 9 days, while 12 days showed the lowest grain
yield.
Sehly et al., (2001,b) studied the effect of four irrigation intervals (3,
6, 9 and 12 days) on rice production. They found that, rice grain yield was
negatively affected with prolonged irrigation intervals. The highest yield was
obtained at 3 days (8.65 t. ha-1
) or 6 days intervals (8.38 t. ha-1
) without
significant difference between each other while, the lowest values were
obtained at 12 days intervals (4.6 t. ha-1
).
Belder et al., (2002) stated that savings in irrigation water in the
alternately submerged and non-submerged (AS & NS) were 13 – 16%
compared with continuously submerged (CS) regime. Rice grain yield was

5
not significantly affected by the water regimes. Water productivity was
significantly higher in the AS & NS regime than CS regime which recorded
(1.48 and 0.91 kg/m3
), respectively.
El-Refaee (2002) reported that, water withholding for 12 days
throughout the growing season significantly decreased dry matter production,
plant height, panicle length, number of tillers/m2
, number of panicle/m2
,
number of filled grains/panicle, 1000-grain weight, panicle weight, grain
yield, straw yield and harvest index while, 12 days water withholding
significantly delayed the heading date.
Gani et al., (2002) studied the effect of different irrigation
management (flooded and intermittent irrigation) and organic matter
amendments at the rate of (0, 3 and 6 ton manure/ha) on rice crop. Results
indicated that intermittent irrigation recorded the highest values of growth
and yield parameters compared with flooded irrigation. On the other side,
crop performed better with 3 ton manure/ha than with 0 or 6 ton manure/ha.
Shi et al., (2002) studied the performance of rice under different
water treatments namely (flooded, intermittent and dry cultivation). Results
showed that intermittent irrigation recorded the highest values of number of
panicles/hill, number of grains/panicle and 1000-grain weight meanwhile,
reduced irrigation water use considerably (27 – 37%) compared with flooded
rice cultivation while at the same time yields increase slightly (4 – 6%). On
the other hand, dry cultivation treatment showed the worst yield performance
for all tested rice varieties. Water use efficiency (WUE) was highest in the
dry-cultivation treatment since yields decreased relatively less than the
supplied of irrigation water.
Belder et al., (2005) investigated the effect of irrigation regimes on
grain yield and nitrogen uptake on hybrid and inbred rice cultivars. Grain
yield ranged from 4.1 t ha-1
in (0-N) to 9.5 t ha-1
with (180 kg N ha-1
).
Alternately submerged-non-submerged regimes showed 4-6% higher yield
than continuous submergence. In all seasons, N application significantly
increased grain yield largely through an increased biomass and grain number.
Water productivity was significantly increased by N application. Water
saving regimes also increased water productivity under non-water-stressed
conditions compared with continuous submergence.

6
El-Refaee et al., (2005,a) in Egypt tested the effect of four irrigation
treatments namely, alternate 4 days on with 6, 8, 10 and 12 days off on
growth, productivity and some grain quality characters of rice varieties Giza
178 and Sakha 102. They found that, growth attributes, yield and its
components as well as some grain quality characters of the two rice varieties
were significantly influenced by irrigation treatments in both seasons.
Treatment one (4 days on + 6 days off) gave the highest values while,
treatment four (4 days on + 12 days off) recorded the lowest values. Giza 178
rice variety was less affected by increasing the off period and produced
higher grain yield. However, Sakha 102 variety gave best grain quality
characters.
Gewaily (2006) investigated the effect irrigation intervals namely
continuous flooding, irrigation every 6 days and irrigation every 9 days on
rice yield and yield components of Sakha 101 rice variety. The result
revealed that, rice yield and its components were significantly affected by
irrigation intervals where, yield decreased as interval period increased in both
seasons.
Jiang-Tao et al., (2006) studied the effect of flooded soil (FS), non-
flooded soil with straw mulching (SM) and non-flooded soil without straw
mulching (ZM) on water use efficiency (WUE) and agronomic traits in rice.
The results showed no significant differences between (FS) and (SM) on flag
leaf area (cm2
), number of effective tillers, total number of grains and grain
yield (kg/ha). On the other side, (ZM) recorded the highest values of unfilled
grain rate (%) and (SM) treatment recorded the highest values of WUE
(kg/m3
). On the other hand, there were no significant differences among all
irrigation treatments on 1000-grain weight.
El-Agamy et al., (2007) investigated the effect of different rice husk
rates (0, 1, 2, 3 and 4 t/fed) under different irrigation intervals (4,8 and 12
days) on the productivity of Giza 178 rice cultivar. They found that,
increasing rice husk rates up to 3 t/fed significantly increased vegetative
growth characters, yield and its components as well as improving grain
quality characters. On the other hand, these characters under study decreased
due to increasing irrigation intervals up to 12 days during both seasons,
however insignificant effect was observed with panicle characters.

7
Zinolabedin et al., (2008) studied the effect of different water stress
conditions namely (water stress during vegetative, flowering and grain filling
stages and well watered was the control) on yield and yield components of
rice (Oryza sativa L.). The results indicated that water stress at vegetative
stage significantly reduced plant height of all cultivars. Water stress at
flowering stage had a greater grain yield reduction than water stress at other
times. The reduction of grain yield largely resulted from the reduction in
fertile panicle and filled grain percentage. Water deficit during vegetative,
flowering and grain filling stages reduced mean grain yield by 21, 50 and
21% on average in comparison to control respectively. Total biomass, harvest
index, plant height, filled grain, unfilled grain and 1000 grain weight were
reduced under water stress in all cultivars. Water stress at vegetative stage
effectively reduced total biomass due to decrease of photosynthesis rate and
dry matter accumulation.
Tran et al., (2008) quantified the impact of new irrigation method
(alternate wetting and drying: AWD) on grain yield, water productivity and
economic efficiency under different seeding rates and nitrogen application
methods in comparison with the conventional water management, continuous
flooding (CF). The two water regimes were physically separated in the plots
to ensure that seepage of water did not interfere together. They found that the
grain yields were varied from 2.68 to 2.76 tons ha-1 in 2006 wet season (WS)
and from 5.81 to 5.98 tons ha-1 in 2007 dry season (DS) at AWD, while
higher grain yields attained at CF. It got the grain yields from 2.75 to 2.90
tons ha-1and from 6.03 to 6.10 tons ha-1, respectively. The differences in
grain yield were significant only in 2007 DS. Although the higher grain
yields of CF, the AWD reduced the irrigation water inputs compared to those.
It reduced 33.3% of irrigation water input in 2006 WS and 28.6% in 2007
DS. Water productivity of AWD was also increased compared to CF. It got
1.4 kg m-3 and 0.9 kg m-3 in 06 WS and 1.6 kg m-3 and 1.2 kg m-3 in 07
DS, respectively.
Amiri et al., (2009) studied the effect of 4 irrigation management
include submerge irrigation, 5, 8 and 11 day intervals on 8 varieties include
local varieties, breeding varieties and hybrid variety under pot conditions. In
maturity time, yield measurement, plant height, panicle length, weight of 100

8
grain, amount of irrigation, number of grains /panicle, total biomass and
number of tillers in pot were done. Results of mean comparison between
irrigation management show that yield, plant height, panicle length, weight of
100 grain and number of grains /panicle in submerge and 5 day interval
irrigation management are placed to one group, therefore it can be
recommended that 5 day interval irrigation are placed on submerge irrigation.
Jalota et al., (2009) examined the effect of two irrigation schedules
(2-days drainage period and at soil water suction of 16 kPa) on water saving
and water productivity of rice. Managing irrigation water schedule based on
soil water suction of 16 kPa at 15-20 cm soil depth increased water saving
and water productivity by 50% but the yield was reduced by 4% compared to
2-days drainage.
Wan et al., (2009) investigated the effect of water deficit on rice
plants varies substantially according to cultivars. Drought tolerant cultivars
possess better morphological, physiological and biochemical adaptation to
reduce water availability. The varieties were taken from both traditional
(Muda, Jawi Lanjut and newly breed commercial varieties, MR 84, MR219
and MR 220) obtained from Genebank, MARDI Research Station, Seberang
Prai, Kepala Batas, Pulau Pinang. These varieties were exposed to two
different water regimes; water stress by withholding water and well watered
condition (control). They found that, water stress plants exhibited lower
growth rate with obvious variation among rice varieties on the sensitivity to
water stress. Meanwhile, the overall sensitivity of the varieties to water stress
was ranked in the order; MR220>Muda>MR84>MR219>Jawi Lanjut. Water
deficit decreased stomatal conductance, relative water content and root depth
while peroxidase activities and proline accumulation were increased in rice
grown under water stress treatment.
Singh et al., (2010) stated that increasing the ponding depth to 15 and
20 cm causes progressive reduction in rice yield, with a marked increase in
seepage, percolation and irrigation water requirement. Decreasing the
floodwater depth in rice fields from 5–10 cm to zero reduces the hydrostatic
pressure, thereby reduces water loss through percolation. Rice grown under
saturated soil culture or alternate wetting and drying (intermittent flooding)
treatments will have little water loss through seepage and percolation.

9
Saturated soil culture decreased water use by 5-50% (average 23%) but
reduced rice yields by 0-12% (average 6%).
Yadav et al., (2011) studied the effect of dry seeded rice (DSR) and
puddled transplanted rice (PTR) on water productivity. There were four
irrigation schedules based on soil water tension (SWT) ranging from
saturation (daily irrigation) to alternate wetting drying (AWD) with irrigation
thresholds of 20, 40 and 70 kPa at 18-20 cm soil depth. There were large and
significant declines in irrigation water input with AWD compared to daily
irrigation in both establishment methods. Yields of PTR and DSR with daily
irrigation and a 20 kPa irrigation threshold were similar each year, thus
irrigation and input water productivity was highest with the 20 kPa irrigation
threshold. An irrigation threshold of 20 kPa was the optimum in terms of
maximizing grain yield and water productivity and reducing irrigation input
by 30-50%.
Abbasi et al., (2012) in a greenhouse research studied the effect of
soil water conditions (continuous submergence, alternate submergence and
alternate saturation), sewage sludge and chemical fertilizers on growth
characteristics and water use efficiency of rice (Oryza sativa L.). The results
showed that, alternate saturation with application of 40 g sewage sludge /kg
of soil achieved optimum growth of rice plant and increase of WUE.
El-Rafaee (2012) investigated the effect of rice straw compost on
growth and grain yield as well as water productivity of Egyptian hybrid rice
(EHR1) under three irrigation regimes namely, continuous flooding (CF) and
irrigation to 5-6 cm depth (-3) and (-6) days after disappearance of surface
water (DADSW). Result indicated that, CF and (-3) DADSW treatments
registered significant and higher values of leaf area index (LAI), dry matter
production, plant height, number of panicle/m2
, panicle length, total number
of grains/panicle, panicle weight, 1000-grain weight, grain yield and straw
yield compared with (-6) DADSW treatment, except for number of days to
50% heading and unfilled grains %. On the other hand, CF consumed the
highest amount of water while, application of (-3) DADSW recorded the
highest water productivity with water saved 11.5 and 11.2 % compared to CF
in both seasons, respectively.

11
Yao et al., (2012) worked on alternate wetting and drying conditions
(AWD) and continuously flood-irrigated (CF) conditions across different
levels of nitrogen input on grain yield and other related traits of
Yangliangyou6 hybrid rice variety (HR) and Hanyou a water-saving and
drought-resistance rice variety (WDR) in 2009 and 2010 seasons. Grain
yield, yield attributes, total water input, water productivity and nitrogen use
efficiency were measured. AWD saved 24% and 38% irrigation water
compared with CF in 2009 and 2010 seasons, respectively. There was
insignificant difference in grain yield values between AWD and CF. On
average HR variety produced 21.5% higher yield than WDR variety under
AWD conditions. Like grain yield, HR variety showed consistently higher
water productivity and physiological nitrogen use efficiency than WDR
variety. These results suggest that high yielding varieties developed for
continuously flood-irrigated rice system could still produce high yield under
safe AWD experienced in this study. Hybrid rice varieties do not necessarily
require more water input to produce high grain yield.
2. Effect of tillage systems on growth characters, yield and its
attributes:
Kushwaha et al., (2000) studied the effect of six combinations of
tillage (conventional, minimum and zero tillage) and crop residue
manipulation (retained or removed) conditions on soil microbial biomass C
(MBC) and N (MBN), N-mineralization rate and available-N concentration.
The proportion of MBC and MBN in soil organic C and total N contents
increased significantly in all treatments compared to control in minimum
tillage residue removed (MT-R) treatment. In all treatments concentrations of
N in microbial biomass were greater at seedling stage, thereafter these
concentrations decreased drastically (21-38%) at grain-forming stage of both
crops. In residue removed treatments, N-mineralization rates were maximum
during the seedling stage of crops and then decreased through the crop
maturity. In residue retained treatments, however, N-mineralization rates
were lower than in residue removed treatments at seedling stage of both
crops. Zero tillage alone (ZT-R) as well as in association to residue retention
(ZT+R) decreased the levels of available N. Tillage reduction and residue
retention both increased the proportion of organic C and total N present in
soil organic matter as microbial biomass. Microbial immobilization of

11
available-N during the early phase of crops and its pulsed release later during
the period of greater N demand of crops enhanced the degree of
synchronization between crop demand and N supply.
Anders et al., (2006) illustrated that over 7 years’ data collected in
this study, no-till managed plots had grain yields equal to or higher than
conventional-till plots in 6 of the 7 years. Over all years, there was less yearly
variation in the no-till treatments when compared to the conventional-till
treatments. With lower production costs in the no-till treatments, it is
expected that net income for the no-till treatments will be higher and more
stable than for the conventional-till treatments. This comparison was made
using the same management, other than tillage, for all plots. These results
suggest that it is possible to switch from conventional-till to no-till and keep
other management aspects the same.
Tomar et al., (2006) studied the influence of tillage systems and
moisture regimes on soil physical environment, root growth and productivity.
Results indicated that root volume of rice crop was significantly affected by
tillage systems and moisture regimes, where significantly higher root volume
was recorded under puddled compared to direct seeded condition. Also, the
highest root volume was found with conventional puddling (31.9 cc) and
lowest with reduced tillage (24.5 cc) indicating the favorable effect of
puddling on root growth in puddled layers. Concerning, rice grain yield was
significantly affected by tillage systems as well as moisture regimes and the
interactions were significant. Considerably higher grain yield was recorded
under puddled (4.00 t/ha) compared to direct seeded (2.34 t/ha) condition
which might be due to reduced percolation losses of water and nutrients
puddled rice. Significantly higher grain yield (4.13 t/ha) was recorded with
conventional compared to reduced puddling (3.88 t/ha). In direct seeded rice,
significantly higher grain yield was obtained with conventional (2.49 t/ha)
compared to reduced (2.19 t/ha) tillage.
Chen et al., (2007) investigated the influence of no-tillage cultivation
on leaf photosynthesis of rice plants in compared to conventional cultivation
under field conditions. Grain yield was constant under no-tillage cultivation
and conventional cultivation. In comparison with the conventional
cultivation, no-tillage cultivation showed less biomass accumulation before

12
heading and higher capacity of matter production during grain filling. A
significantly higher leaf net photosynthetic rate was observed for the plants
under no-tillage than for those under conventional tillage. The fluorescence
parameter (Fv/Fm) in leaf did not show any difference between the two
cultivations. The effect of cultivation management on transpiration rate (Tr)
and SPAD value of rice leaf was not significantly affected by the two
cultivation.
Liu et al., (2007) studied effect of interplanting with zero tillage and
straw manure on rice growth and quality, an experiment was conducted in a
wheat-rotation rotation system. Four treatments namely, ZIS (Zero-tillage,
straw manure and rice interplanting), ZI (Zero-tillage, no straw manure and
rice interplanting), PTS (Plowing tillage, straw manure and rice
transplanting), and PT (Plowing tillage, no straw manure and rice
transplanting), were used. ZIS reduced plant height, leaf area /plant and the
biomass of rice plants, but the biomass accumulation of rice at the late stage
was quicker than that under conventional transplanting cultivation. In the first
season there was no significant difference in rice yield among the four
treatments. However, rice yield decreased in interplanting with zero-tillage in
the second season compared with the transplanting treatments, the number of
filled grains /panicle decreased but 1000-grain weight increased in
interplanting with zero-tillage, which were the main factors resulting in
higher yield. Interplanting with zero-tillage improved the milling and
appearance qualities of rice. The rates of milled and head rice increased while
chalky rice rate and chalkiness decreased in interplanting with zero-tillage.
Zero-tillage and interplanting also affected rice nutritional and cooking
qualities.
Zein EL-Din et al., (2008) studied the effect of different land
preparation methods, conventional tillage (CT) and reduced tillage (RT)
combined with different planting systems, random manual transplanting, row
transplanting (20X20 cm) and mechanical drilling of two rice variety Giza
182 and Sakha 101. The results indicated that the maximum total grain yield
with respect to planting systems was achieved with mechanical drilling
system combined with conventional tillage treatment (3.045 t/fd). In addition,
mechanical drilling with conventional tillage (CT) gave higher values of

13
yield components (number of tillers/m2
- number of filled grain/panicle and
1000 grain weight) compared to the same planting system under reduced
tillage. Concerning, head rice percentage (HRP) resulted higher values in
conventional tillage treatment (CT) with mechanical drilling than other
treatment.
Devkota et al., (2010) used six frequent intermittent WAD irrigated
rice treatments from the combination of Bed planting (BP) and zero tillage
(ZT) with three levels of residue retention (all residue harvested (RH), 50%
residue retention (R50) and 100% residue retention (R100) on rice
productivity. These treatments were compared with the farmers’ practice of
conventional tillage flood irrigation (CT-FI) and a conventional tillage
intermittent irrigation (CT-II). The yield loss of rice in the WAD treatments
was on average 42%. Reduction in the number of spikelets appeared to be the
key cause of rice yield decline under water saving irrigation. This was largely
due to soil water and nitrogen stresses observed during the rice grain setting
phase. Low soil mineral N content together with poor crop performance in
WAD rice indicates (i) water stress reduced crop N demand or, (ii) soil
conditions led to increased N losses via. nitrification-denitrification and/or
ammonia volatilization and/or leaching resulting to poor crop demand and
uptake. Both intensive tillage and greater amount of residue retention did not
have any beneficial effect on rice yield. Despite the lower yield, the concept
of WAD rice combined with CA technologies can have enormous water
saving potential. Improvement in agronomic practices to increase N and
water use efficiency and the use of improved aerobic rice varieties can reduce
the yield gap between WAD and paddy rice. The amount of water applied in
zero tillage (ZT) was greater than in bed planting (BP) by 19% in 2008
season and 18% in 2009 season. No significant interactions were observed
between BP and ZT with three levels of residue retention. The water
productivity of rice was significantly affected by irrigation, tillage, and
residue levels in both years; hence, it was greater in treatments of WAD rice
than in CT-FI. In addition, RH had greater water productivity than the residue
retained treatments. Water productivity in CT-II was equal with RH
treatments of WAD rice.

14
Virdia and Mehta (2010) conducted a field trial during 1997 to 2007
at Vyara-Gujarat, to study effect of tillage management in rice (Oryza sativa
L.)-groundnut (Arachis hypogaea) cropping system. Ploughing 6 deep every
season or every year proved a better for higher grain yield. Further, deep
ploughing once or twice in year improve rice based equivalent gross income,
net return and benefit: cost ratio. Additional expenditure (aprox Rs. 3000) for
ploughing was compensated by additional net income (aprox Rs. 5000)
Jiang et al., (2011) suggested that ridges with no tillage (RNT) in
subtropical rice soils may be a better way to enhance soil productivity and
improve soil C sequestration potential than conventional tillage (CT). The
highest SOC was in the 1.00–0.25 mm fraction (35.7 and 30.4 mg ⁄ kg for
RNT and CT, respectively), while the lowest SOC was in micro aggregate
(<0.025 mm) and silt + clay (<0.053 mm) fractions (19.5 and 15.7 mg ⁄ kg for
RNT and CT, respectively). Tillage did not inﬂuence the patterns in SOC
across aggregates but did change the aggregate-size distribution, indicating
that tillage affected soil fertility primarily by changing soil structure.
Xianjun et al., (2011) mentioned the tillage effects on soil
nitrification kinetics at the aggregate scale were studied for a subtropical rice
soil. Soil samples were separated into large aggregates (>2.0 mm), macro-
aggregates (2.0–0.25 mm), micro-aggregates (0.25–0.053 mm) and silt + clay
fractions (<0.053 mm) by wet-sieving. The net nitrification process was
simulated by a zero and first kinetics model. Conventional tillage (CT)
increased the proportion of the silt + clay fraction by 60% and decreased
large-aggregates by 35% compared to ridge with no-till (RNT). Regression
analysis showed that the time-dependent kinetics of net nitrification were best
fitted by a zero-ordermodel for the large-aggregates and silt + clay fraction
but a first-order kinetic model for macro- and microaggregates and whole
soil, regardless of tillage regime. Both potential nitrification rates (Vp) and
net nitrification rates (Va) were higher for macroaggregates than
microaggregates. The potential nitrification (Np) for whole soil under RNT
was 38.7% higher than CT. The Vp and Va for whole soil was 88.5% and
64.7% higher under RNT than CT, respectively. Although nitrification was
stimulated under RNT, the kinetics model of nitrification was not affected by
tillage. This inferred that the interaction between substrates and enzymes

15
involved in nitrification associated with aggregates was not altered by tillage.
For this soil, nitrifying microorganisms were mainly associated with macro
and microaggregates rather than large-aggregates and silt + clay fractions.
Kumar et al., (2012) stated that, dry seeding of rice reduced water
inputs and tillage costs compared with the conventional system of rice
cultivation. The yields of rice in conventional puddled transplanting were
higher as compared to, unpuddled transplanting, reduced-till transplanting,
and direct-seeding systems. Zero-tillage transplanted and reduced till dry-
direct-seeded rice had a higher net return than the conventional and
unpuddled system. In addition, the conventional practice of puddled
transplanting could be replaced by unpuddled and reduced tillage–based crop
establishment methods to save water and labor and achieve higher income.
Singh et al., (2013) examined the effect of two methods of rice
cultivation conventional transplanting CT (standing water was maintained in
crop growing season) and system of rice intensification SRI (soil was kept at
saturated moisture condition throughout vegetative phase and thin layer of
water 2–3 cm was maintained during the reproductive phase of rice) and two
rice varieties (Pusa Basmati 1 and Pusa 44). Results revealed that CT and SRI
gave statistically at par grain yield but straw yield was significantly higher in
CT as compared to SRI. Seed quality was superior in SRI as compared to CT.
The grain yield and its attributes of Pusa 44 were significantly higher than
those of Pusa Basmati 1. CT rice used higher amount of water than SRI, with
water saving of 37.6% to 34.5% in SRI. Significantly higher water
productivity was recorded in SRI as compared to CT rice.
Karim et al., (2014) evaluated yield and resource use efficiency of
transplanted Boro rice under two tillage and three irrigation methods. Two
tillage methods viz., conventional tillage with puddle transplanted rice and
reduced tillage unpuddled transplanted rice and three irrigation methods viz.,
sprinkler irrigation, alternate wetting and drying (AWD) and flood irrigation
were used as treatment variables. Irrespective of tillage methods, reduced
tillage method holds 4.62% higher yield production over conventional tillage
method. Water use efficiency was found highest in sprinkler irrigation
method (0.83 kg/m3) and in reduced tillage method (0.773 kg/m3). Labour
required for land preparation was 15 md/ha in reduced tillage, whereas it was

16
38 md/ha in conventional tillage method. Seedling uprooting and
transplanting required higher labour in reduced tillage method over
conventional tillage. Fuel consumptions (49.78 l/ha) and electricity (3475.11
Kwhr/ha) was also less in reduced tillage method. Reduced tillage had less
land preparation and fuel cost over conventional tillage method. But seedling
uprooting and transplanting cost was higher in reduced tillage.
3. Effect of varietal differences on growth characters, yield and its
attributes:
El-Refaee, et al., (2005a) illustrated the influence of 3 irrigation
intervals (3, 6 and 12 days) on some growth, yield and its attributes
characters of eight rice cultivars namely, Sakha101, Sakha102, Sakha103,
Sakha104, Giza177, Giza178, Giza182 and Egyptian Yasmine during 2002
and 2003 rice growing seasons. The result revealed that, most growth
analysis and attributes as well as yield and its components were significantly
affected by the rice cultivars. Dry matter production, plant height, number of
tillers/m2
, number of panicle/m2
, panicle length, total grains/panicle, panicle
weight, 1000-grain weight, grain yield, straw yield and grain/straw ratio
significantly decreased as irrigation intervals increased up to 12 days in both
seasons. On the other hand, unfilled grains % and panicle density increased
during both seasons.
Gomez et al., (2005) investigated the effects of mean root length, and
root weight on biological yield of 11 rice cultivars, including drought
resistant ones. Correlations studies showed that root weight were positively
correlated with biological yield. Leaf area /plant showed the highest positive
direct effect on root weight, followed by biological yield.
Naoki and Toshihiro (2009) evaluated the genotypic differences in
growth, grain yield, and water productivity of six rice (Oryza sativa L.)
cultivars from different agricultural ecotypes under four cultivation
conditions: continuously flooded paddy (CF), alternate wetting and drying
system (AWD) in paddy field, and aerobic rice systems in which irrigation
water was applied when soil moisture tension at 15 cm depth reached −15
kPa (A15) and −30 kPa (A30). In three of the six cultivars, they measured

17
bleeding rate and predawn leaf water potential (LWP) to determine root
activity and plant water status. The improved lowland cultivar, Nipponbare
gave the highest yield in CF and AWD. The improved upland cultivar,
UPLRi-7, and the traditional upland cultivar, Sensho gave the highest yield in
A15 and A30, respectively. The yields of traditional upland cultivars, Sensho
and Beodien in A30 were not lower than the yields in CF. However, the
yields of the improved lowland cultivars, Koshihikari and Nipponbare, were
markedly lower in A15 and A30. The water productivity of upland rice
cultivars in aerobic plots was 2.2 to 3.6 times higher than that in CF, while
those of lowland cultivars in aerobic plots were lower than those in CF. The
bleeding rate and LWP of Koshihikari was significantly lower in A15 and
A30 than in CF and AWD, but Sensho and Beodien showed no differences
among the four cultivation conditions. They conclude that aerobic rice
systems are promising technologies for farmers who lack access to enough
water to grow flooded lowland rice. However, lowland cultivars showed
severe growth and yield reductions under aerobic soil conditions.
Abd Allah et al., (2010) studied the performance of thirty-three
entries of rice under normal and drought conditions to examine the
magnitude of yield response of diverse genotypes to drought stress and to
identify traits that may confer drought resistance. Analysis of variance
indicated highly significant differences among the genotypes for all the traits
studied. Many promising lines of rice were found to be tolerant against
drought stress at different growth stages i.e. seedling stage, early and late
vegetative stage, panicle initiation stage and heading stage. These lines
possess useful traits associated with drought tolerance such as early maturity
(drought escape mechanism), medium tillering ability, medium plant height,
root depth, root thickness, root volume, dry root: shoot ratio, plasticity in leaf
rolling and unrolling (drought avoidance mechanism), in addition to crop
water use efficiency and water application efficiency. Among the traits
studied viz. number of tillers /plant, number of panicles /plant, 100 grain
weight, panicle weight, revealed significant genotypic correlation with grain
yield. Also, number of filled grains /panicle depicted the highest direct
contribution of 0.630 and it also show highest indirect contribution of 0.867
followed by 100 grain weight (0.850) towards grain yield.

18
Ndjionjop et al., (2010) evaluated the effect of drought on some rice
(Oryza sativa L.) genotypes according to their drought-tolerance levels. The
results showed a consistent negative effect of drought on plant height and
grain yield across genotypes’ drought-tolerance levels and also across
genotype types. Plant height (up to 20.9 cm reduction) and grain yield (up to
1700.8 kg/ha reduction) were more reduced for sensitive genotypes than for
moderately tolerant (maximum reductions of 14.9 cm and 1509.5 kg/ha) and
tolerant genotypes (maximum reductions of 14.0 cm and 972.8 kg/ha).
Flowering (start, 50%, and 100%) and maturity were consistently delayed
across genotype types and tolerance levels. Mean delays of 6.5, 21.8, and 9.4
days were observed for start, 50%, and 100% flowering, respectively.
Maturity was also delayed, with consistency across genotype types. However,
no clear picture of the drought effect on flowering and maturity was observed
in terms of differences among drought-tolerance levels. The effects of
drought both of number of tillers and leaf temperature were not consistent.
Plant height and grain yield showed the clearest differences between
genotype-tolerance levels in the genetic material evaluated.
El-Refaee et al., (2011) concluded that hybrid cultivars (Egyptian
hybrid 1 and SK2058H) achieved the highest grain yield production, the
highest values of water use and utilization efficiency. Giza 171 (long duration
cultivar) achieved the highest amount of water input, the lowest values of
water use, water utilization and water application efficiencies and the highest
percentage of water loss. However, short duration cultivars (Giza 177, Giza
182, Sakha 102, Sakha 103 and Sakha 105) recorded the lowest values of
total water input and water loss as well as gave the highest value of water use
efficiency and water application efficiency. The economic evaluation showed
that short duration cultivars (especially Sakha 105) and medium duration
cultivars (especially hybrid cultivars) enhanced irrigation efficiency and rice
productivity. So, it is important to enhance farmer’s acceptance of short
duration and hybrid rice cultivars by improving their yields and its grain
quality.
El-Mouhamady et al., (2013) investigate in the greenhouse from
October 2009 to March 2010 included two main conditions, i.e. normal
irrigation and water stress every 15 days using Line x tester analysis through

19
the parents (Sakha 102 and Agami) were used as testers, while; the cultivars
Giza 171, Giza 172, Gaori and Giza 159 were used as lines, and markers
assisted selection techniques used a random primer namely; A17, A18 and
As-467468 as indication for drought tolerance in rice. The main studied
characters were yield and its components;(heading date, plant height, number
of panicles/plant, number of filled grains/panicle, 1000-grain weight and
grain yield/plant) and some characters related to drought namely; (maximum
root length, number of roots/plant, root volume, root xylem, vessels number
and root dry weight), respectively under normal and drought conditions.
Heterosis over better parent, general and specific combining ability effects
were studied as a genetic components. The most desirable mean value,
positive and highly significant of heterosis, general and specific combining
ability effects for all traits studied using line x tester design under the two
conditions were shown in the genotypes; Agami, Gaori, Sakha 102 × Gaori,
Agami × Gaori and Agami × Giza 159. From the foreign discussion, it could
be concluded that, the crosses; Agami × Gaori, Agami × Giza 159 and Sakha
102 × Gaori were contained of the bands number 1, 2 and 6 for A17 primer 3,
6 and 7 bands for A18 primer and the bands number 3, 4, 5, 7, 8 and 9 for
As-467468 primer under drought conditions which indicated that these bands
were found to be index for drought tolerance in rice. So these crosses would
be effective and important for grown as lines of drought tolerance in rice.

21
III. MATERIALS AND METHODS
Two field experiments were conducted at the Experimental Farm in
Itay El-Baroud, Agricultural Research Station, El-Behaira Governorate,
Agricultural Research Center (ARC), during 2011 and 2012 seasons to
evaluate Egyptian Hybrid 1, Giza 178, Sakha 104 and Sakha 101 rice
cultivars under different water regimes and tillage systems.
1. Experimental layout
Treatments were arranged in a split-split-plot design with three
replications in the two seasons of study. Where, the main plots were
designated for irrigation treatments, while sub-plots were designated for
tillage systems and sub-sub-plots were designated for rice cultivars.
2. Treatments
2.1 Irrigation regimes:
Water consumption during growing season is about 6000 m3
/fad., where
nursery bed and land preparation need about 1680 m3
/fad., as constant
amount of water under any irrigation interval and equal amount of water (180
m3
/fad.) was added every 4, 6 and 8 days. Nursery needs about 30 days and
exposed 15 days to withholding before harvesting, consequently rice plants
under study need 95 days of irrigation during its growth period. The
irrigation regimes can be summarized as follow:-
Irrigation treatments
No. of
irrigations
Nursery
&land
preparation
Water used
(m3
/fad.)
Water
saving
Irrigation every 4 days 24×180 m3
1680 m3
6000 m3
/fad. --
1680 m3
4560 m3
/fad. 24 %
1680 m3
3840 m3
/fad. 36 %
In general, irrigation every 4, 6 and 8 days rice plant need 24, 16 and
12 irrigations, respectively. The total water consumption after transplanting
for irrigation every 4, 6 and 8 days in one growing season was 4320, 2880
and 2160 m3
/fad., respectively.

21
2.2 Tillage systems:
1. Recommended tillage (Conventional tillage); the plots were prepared by
twice plowing and harrowing then carefully dry leveled.
2. Zero tillage (No tillage) just removes the residual straw of previous crop.
2.3 Rice cultivars
Four rice cultivars (Egyptian Hybrid 1, Giza 178, Sakha 104 and Sakha
101) were evaluated in this study with about 140 days duration period. The
pedigree, group type and main characters of these cultivars are shown in
Table (1).
Table (1): Origin and main characteristics of the four rice cultivars.
Varieties Origin Salient features
Egyptian
Hybrid 1
(IR 69625/Giza 178)
Japonica type, medium maturing,
short grain, semi-dwarf, high yield
and resistant to blast.
Giza 178 (Giza175/Milyang 49)
Indica-Japonica type, medium
maturing, short grain, semi-dwarf,
high yield and resistant to blast.
Sakha
104
(GZ4096-8-1/GZ4100-9)
medium grain, semi-dwarf, high
yield and susceptible to blast.
Sakha
101
( 176/ Milyang 79)
medium grain, semi-dwarf, high
yield and susceptible to blast.
3. Cultural practices
Raising nursery
Nursery area was well ploughed and dry leveled after removing the
wheat residues. Phosphorus fertilizer in the form of mono super phosphate
(15.5% P2O5) was added in dry soil at the rate of 100 kg/fad. before the first

22
tillage. Nitrogen as urea (46.5% N) at the rate of 60 kg N/fad. was added and
incorporated into the dry soil after the last plowing and immediately before
first irrigation. Zinc sulphate (22% Zn) at the rate of 24 kg Zn/fad. was added
after puddling and before sowing the nursery. Seeds of the rice cultivar
(Egyptian Hybrid Rice (Hybrid 1) was added at the rate of 10 kg/fad., while
Giza 178, Sakha 104 and Sakha 101 added at the rate of 60 kg/fad.). In all
cases, the seeds were soaked in excess water for 24 hours then incubated for
48 hours to enhance germination and broadcasted to the nursery in 10th
of
May in both seasons.
The permanent field
After removing the previous wheat crop, the experimental site was
prepared according to randomized distribution of tillage systems
(Recommended tillage and Zero tillage) in the sup-plots. Each replicate was
divided into three parts (Irrigation treatments) by ditches to prevent water
movement among water treatments plots. Phosphorus fertilizer in the form of
mono super phosphate (15.5% P2O5) was added at the rate of 100 kg/fad. as
basal application. Nitrogen fertilizer as urea (46.5% N) source added at the
rate of 60 kg N/fad. in to two splits. Two-thirds of the nitrogen dose as first
split was incorporated into the dry soil immediately before first irrigation and
the second split (1/3 of total nitrogen dose) was tope dressed on the plants
after thirty days from transplanting. Thirty days old seedlings were
transplanted regularly in the sub-sub-plots with the plot area of 15 m2
(3×5
m) and the distance between hills and rows was 20×20 cm to give 25
hills/m2
. Other cultural practices of rice growing were performed as the
recommendations of Rice Research and Training Center (RRTC).
4. Studied characters:
A- Growth characters:
1- Root volume (cm3
):
At panicle initiation stage, randomly three hills were collected from
each sub-sub-plot as a whole plant (shoots and roots) using a metal
cylinder in 25X60 cm dimension to get unique volume from root zone.
Volume of the plant root system was determined by cubic centimeters.

23
2- Root length (cm):
Root length was determined as the length of the root from the base
of the plant to the tip of the main axis of primary root.
3- Root: shoot ratio:
Ratio of the root dry weight (g) to the shoot dry weight (g) was
calculated.
4- Number of days to heading (days)
It was recorded as the number of days from sowing up to about 50%
of heading attained.
5- Plant height (cm)
Main culm height was measured at harvest time from the soil surface
up to the top of the tallest culm.
)
At heading time, plant samples (5 hills from each sub-sub-plot) were
randomly collected and flag leaf area was determined according to
(Yoshida, 1981).
B- Yield and yield components
1- Number of productive tillers/m2
:
Number of productive tillers/m2
was counted as the average of ten
hills from each sub-sub-plot when all panicles were counted at full ripe
stage.
2- Number of filled grains / panicle:
Number of filled grains / panicle was counted from ten randomly
collected panicles of each sub-sub-plot and the average of grain number /
panicle was calculated.
3- 1000-grain weight (g):
Mean one thousand paddy rice grains were weighted to the nearest
0.01 gram from each sub-sub-plot.
4- Unfilled grains percentage:
Unfilled grains percentage was estimated as average from the same
ten panicles and it was calculated as follows:

24
5- Panicle weight (g):
Panicle weight was determined as an average of the weight of ten
random panicles from each sub-sub-plot in grams and actual weight was
recorded.
6- Panicle length (cm):
Mean of ten panicle length was measured in cm. from the base of
panicle up to its tip.
7- Biomass yield (ton/fad.):
After a complete maturity of rice grains, inner-ten square meters
from the center of each sub-sub-plot were manually harvested and air-
dried for 4 days after harvesting and weighted.
8- Grain yield (ton/fad.):
The same inner-ten square meters in each sub-sub-plot, were left to
air drying naturally for three days, and then threshed and paddy rice grains
were weighted (kg/10m2
) and adjusted to 14% moisture content, then grain
yield Kg/10 m2
transfer to ton/fad. calculation.
9- Harvest index (%):
It was determined according to (Yoshida 1981) as follows:
C- Water relations
1- Reduction percentage (%)
It was calculated according the following equation:
2- Drought sensitivity index (DSI):
It was calculated for each cultivar according to the formula given
by Ali-Dib et al, 1990.
DSI= (NGY-S)/NS
Where;
NS: is grain yield under normal stress.
S : is grain yield under drought stress.

25
3- Water use efficiency (WUE):
It was determined according to Israelsen and Hansen (1962) as
follows:
water
D- Grain quality characters
Hulling %, milling % and head rice % for all samples were done in
Rice Technology and Training Center (RTTC), Field Crops Research
Institute, Agricultural Research Center, Alexandria, after adjusting moisture
content to (14%). All the grain quality characters are estimated according to
Khush et al., (1979).
1- Hulling percentage
Hulling percentage was determined by hulling 100 grams of
randomly selected grains from each sub-sub-plot by means of hulling
machine. Brown rice was weighted and estimated as a percentage of total
weight of 100 grams.
2- Milling percentage
Milled rice percentage was determined by milling 100 grams of
brown rice by experimental milling machine. The total milled rice was
computed as a percentage relative to the total weight.
3- Head rice percentage
Head rice grains were weighted and then calculated as percent from
the total weight of the rough rice.
5. Statistical analysis
Analysis of variance for the studied characters was calculated
according to procedures of Gomez and Gomez (1984). Differences among
treatments means were compared using the L.S.D at 0.05 and 0.01 levels of
probability.

26
IV. RESULTS AND DISCUSSION
The effects of irrigation regimes and tillage systems on the different
studied characters of Egyptian Hybrid 1, Giza 178, Sakha 104 and Sakha 101
rice cultivars in 2011 and 2012 seasons will be presented and discussed under
the following main topics:
I. Growth characters.
II. Yield and its components characters.
III. Grain quality characters.
IV. Water relations characters.
I)- Growth characters
1-Root volume (cm3
)
Data in Table (2) showed root volume (cm3
) as influenced by
irrigation regimes (A), tillage systems (B) and rice cultivars (C) as well as
their interactions in 2011 and 2012 seasons.
A) Irrigation regimes
It is clear from Table (2) that, root volume was significantly affected
by different irrigation regimes in the two seasons of study. Results showed
highly significant differences among the three irrigation regimes. Root
volume was increased significantly as irrigation water quantities increased
and irrigation intervals decreased, which leads to increase water availability
in the soil. Hence, the largest values of root volume (65.54 and 66.25 cm3
)
were found when rice plants irrigated every 4 days (in 6000 m3
/fad rate of
irrigation water), followed by irrigation every 6 days (60.16 and 60.28 cm3
)
in 2011 and 2012 seasons, respectively. On the opposite, the lowest root
volume was measured at 8 days irrigation regime (in 3840 m3
/fad rate of
irrigation water). These findings agree with the fact that rice grown under
drought conditions normally has slower growth than that growth under
flooded conditions particularly in the vegetative stage. These findings are in
harmony with those obtained by Gaballah (2009) and Wan et al., (2009).

27
B) Tillage systems
Further, results presented in Table (2) revealed that root volume was
highly significant affected by tillage systems. Maximum root volume was
obtained under conventional tillage which ranged between 58.57 and 58.81
cm3
in 2011 and 2012 seasons, respectively. However, the minimum value of
root volume was found when rice plants were transplanted into no tilled soil
(56.23 and 56.47 cm3
) in both seasons, respectively. These results led to the
conclusion that, the soil tillage caused successive improvement of soil
structure which permitted deeper penetration of plant root. Aggrawal et al.,
(1999) observed that the puddling alone in rice enhanced root length density
(RLD) by 12% and root growth of rice in puddled treatment was significantly
higher than in non-puddled treatment and the major portion of roots was
concentrated in 0-0.10 cm soil depth. Another point of view, Xianjun et al.,
(2011) reported that, the potential nitrification and net nitrification rates for
whole soil under no tillage was 88.5% and 64.7% higher than conventional
tillage, respectively. Increasing in the nitrification rate accelerated the rapid
loss of available nitrogen in the soil which negatively effect on plant parts
growth and particularly roots. Generally, the conventional tillage encourages
rice roots to grow better and decrease nitrogen losses.
C) Rice cultivars effects
In addition, Table (2) showed that, rice cultivars had a highly
significant effect on root volume in 2011 and 2012 seasons. The largest root
volume was obtained by Hybrid 1 (70.72 and 70.69 cm3
), followed by Giza
178 (58.61 and 58.97 cm3
) in both seasons. While, the lowest value of root
volume was obtained by Sakha 104 rice cultivar (49.02 and 49.34 cm3
) in
2011 and 2012 seasons, respectively. The different performance for the rice
cultivars under study is due to genetic variations among cultivars. These
findings are in harmony with those obtained by Gaballah (2009) and Abd
Allah et al., (2010)

28
Table (2): Effect of irrigation regimes (A), tillage systems (B), rice cultivars (C)
and their interactions on root volume (cm3
), root length (cm) and root/shoot
ratio of Egyptian hybrid 1, Giza 178, Sakha 104 and Sakha 101 rice cultivars in
2011 and 2012 seasons.
Root volume (cm3
) Root length (cm) Root/shoot ratio
2011 2012 2011 2012 2011 2012
A - Irrig. Regimes:
a1 - 4 Days
a2 - 6 Days
a3 - 8 Days
65.54 a
60.16 b
46.50 c
66.25 a
60.28 b
46.48 c
27.50 a
25.25 b
18.69 c
27.38 a
25.39 b
18.84 c
0.703 a
0.697 a
0.641 b
0.702 a
0.702 a
0.649 b
Ftest ** ** ** ** ** **
L.S.D0.05
L.S.D0.01
-
1.70
-
1.25
-
1.37
-
1.12
-
0.008
-
0.013
B- Tillage systems:
b1 – Conventional tillage
b2 – No tillage
58.57 a
56.23 b
58.81 a
56.47 b
24.56 a
23.06 b
24.59 a
23.15 b
0.684 a
0.676 b
0.688 a
0.681 b
Ftest ** ** ** ** * *
L.S.D0.05
L.S.D0.01
-
0.90
-
0.86
-
0.64
-
0.37
0.006
-
0.005
-
C- Rice cultivars:
c1 - Hybrid 1
c2 - Giza 178
c3 - Sakha 104
c4 - Sakha 101
70.72 a
58.61 b
49.02 d
51.26 c
70.69 a
58.97 b
49.34 d
51.55 c
28.79 a
24.49 b
20.50 d
21.46 c
29.03 a
24.52 b
20.64 d
21.29 c
0.720 a
0.707 b
0.622 d
0.671 c
0.725 a
0.713 b
0.628 d
0.672 c
Ftest ** ** ** ** ** **
L.S.D0.05
L.S.D0.01
-
0.85
-
0.71
-
0.73
-
0.64
-
0.008
-
0.007
Interactions:
Ftest (A × B)
Ftest (A × C)
Ftest (B × C)
Ftest (A × B × C)
*
**
**
**
NS
**
NS
**
NS
**
NS
NS
*
**
NS
NS
NS
**
NS
NS
NS
**
NS
NS
(NS) = Not Significant, (*) = Significant at 0.05 and (**) = Significant at 0.01 level
of probability.
Means followed by the same letters are not significant.

29
The interaction
Figure (1): The interaction between irrigation regimes (A) and tillage
systems (B) for root volume (cm3
) in 2011 season.
In 2011 season, root volume was significantly affected by the
interaction between irrigation regimes and tillage systems (AxB), while no
significant differences were observed in 2012 season. As Figure (1) showed,
the highest value of root volume (66.42 cm3
) was obtained by conventional
tillage under irrigation every 4 days and the lowest value of root volume
(45.67 cm3
) was obtained from no tillage under 8 days irrigation regime in
the first season. Conventional tillage was more effective on root volume
under irrigation every 6 days in compared with both 4 and 8 days irrigation
regimes. That may be due to deep root penetration would help rice to avoid
drought stress; however, root penetration is often restricted by the presence of
a hardpan. These findings agreed with Tomar et al. (2006).
The interaction between rice cultivars and irrigation regimes (AxC)
for root volume was highly significant in the two seasons of study as shown
in Figure (2). Where, the largest root volume (79.80 and 80.67 cm3
) were
recorded by Hybrid 1 when the rice plants irrigated every 4 days, while the
lowest values (38.93 and 39.22 cm3
) of root volume were obtained by Sakha
104 under 8 days irrigation regimes in 2011 and 2012 seasons, respectively.
These results may be due to a greater root of hybrid rice which led to increase
water absorption and elements from the soil than other rice cultivars
particularly under flooded condition. These findings are in harmony with
those obtained by Yang et al., (1999).
NT CT
4 Days 64.67 66.42
6 Days 58.37 61.96
8 Days 45.67 47.33
Root volume (cm3)
2011
LSD 0.05 = 1.03
CT: Convetional tillage
NT: No tillage

31
Figure (2): The interaction between irrigation regimes (A) and rice
cultivars (C) for root volume (cm3
In the same way, the root volume was significantly differed by the
interaction between tillage systems and rice cultivars (BxC) in 2011 growing
season only. Figure (3) showed that the largest root volume was obtained by
Hybrid 1 (71.28 cm3
) when the plants were transplanted in tilled soil while,
the lowest value of root volume (47.91 cm3
) was obtained by Sakha 104
under no tillage. The superiority of Hybrid 1 in root volume under both
conventional and no tillage may be due to the hybrid vigor, which had greater
root absorption ability.
Figure (3): The interaction between tillage systems (B) and rice
cultivars (C) for root volume (cm3
) in 2011 season.
4 Days 6 Days 8 Days
H 1 79.80 71.45 60.91
Giza 178 66.78 62.33 46.72
Sakha 104 55.81 52.32 38.93
Sakha 101 59.78 54.56 39.45
Root volume (cm3)
2011LSD 0.01 = 1.48
H 1 80.67 71.54 59.87
Giza 178 67.50 62.39 47.01
Sakha 104 56.43 52.36 39.22
Sakha 101 60.40 54.85 39.41
Root volume (cm3)
2012LSD 0.01 = 1.23
NT CT
H 1 70.16 71.28
Giza 178 57.38 59.84
Sakha 104 47.91 50.13
Sakha 101 49.48 53.04
Root volume (cm3)
2011
LSD 0.01 = 1.21
CT: Convetional tillage
NT: No tillage

31
Figure (4): The interaction among irrigation regimes (A), tillage systems (B) and
rice cultivars (C) for root volume (cm3
As Figure (4) showed, highly significant differences in root volume as
influenced by the interaction among irrigation regimes, tillage systems and
rice cultivars (AxBxC) in both seasons. Where the largest root volume (80.69
and 82.13 cm3
) were recorded by Hybrid 1 under conventional tillage (CT)
with 4 days irrigation regime while, the lowest values of root volume (37.56
and 37.86 cm3
) were obtained by Sakha 104 under no tillage with 8 days
irrigation regime in 2011 and 2012 seasons, respectively. Deep root
penetration would help rice to avoid drought stress; however, root penetration
is often restricted by the presence of a hardpan. Genotypic variation in the
ability of rice to penetrate compacted soil layers and simulated compact
layers has been shown to exist. These results agreed with those reported by
Clark et al., (2002).
2-Root length (cm)
Data in Table (2) showed root length (cm) as influenced by irrigation
regimes (A), tillage systems (B) and rice cultivars (C) as well as their
interactions in 2011 and 2012 seasons.
H 1
Giza
178
Sakha
104
Sakha
101
H 1
Giza
178
Sakha
104
Sakha
101
NT CT
4 Days 78.91 65.31 55.54 58.90 80.69 68.25 56.08 60.66
6 Days 70.01 61.22 50.63 51.60 72.88 63.44 54.01 57.51
8 Days 61.55 45.61 37.56 37.96 60.27 47.83 40.29 40.94
Root volume (cm3)
2011
LSD 0.01 =
2.10
H 1
Giza
178
Sakha
104
Sakha
101
H 1
Giza
178
Sakha
104
Sakha
101
NT CT
4 Days 79.20 66.26 56.49 59.85 82.13 68.74 56.36 60.95
6 Days 70.30 61.18 50.93 52.22 72.78 63.60 53.78 57.48
8 Days 59.51 45.91 37.86 37.91 60.24 48.10 40.58 40.90
Root volume (cm3)
2012
LSD 0.01 =
1.75

32
It is clear from Table (2) that root length had highly significant
differences as influenced by different irrigation regimes in the two seasons of
study. Results showed highly significant differences among the three
irrigation regimes. Root length was significantly increased as irrigation
regime decreased which, leads to increase water availability in the soil then
increase the growth vigor. Hence, the longest values of root length (27.50 and
27.38 cm) were found when rice plants irrigated every 4 days, followed by
(25.25 and 25.39 cm) measured in 6 days irrigation regime in 2011 and 2012
seasons, respectively. On the opposite, the shortest values of root length
(18.69 and 18.84 cm) were measured at 8 days irrigation regime in 2011 and
2012 seasons, respectively. These findings agree with the fact that rice grown
under drought conditions normally has slower growth than that growth under
harmony with those obtained by Wan et al., (2009).
B) Tillage systems
In addition, results presented in Table (2) revealed highly significant
differences in root length as affected by different tillage systems. Maximum
root length was obtained under conventional tillage (CT), which ranged
between values 24.56 and 24.59 cm in 2011 and 2012 seasons, respectively.
However, the lowest values of root length were found when rice plants were
transplanted in untilled soil (23.06 and 23.15 cm) in both seasons,
respectively. These results led to the conclusion that the soil tillage caused
successive improvement of soil structure which permitted deeper penetration
of plant root. Root penetration is often restricted by the presence of a
hardpan, hence tillage can encourage root to grow deeper. These results
agreed with those reported by Clark et al., (2002).
C) Rice cultivars
In addition, Table (2) showed that rice cultivars had highly significant
effects on root length in 2011 and 2012 seasons, respectively. The longest
root length were obtained by Hybrid 1 (28.79 and 29.03 cm) followed by
Giza 178 (24.49 and 24.52 cm) in both seasons, respectively. While, the
lowest values of root length were obtained by Sakha 104 rice cultivar (20.50
and 20.64 cm) in 2011 and 2012 seasons, respectively. These varietal

33
differences may be due to genetic variations among these cultivars. These
findings agreed with Gaballah, (2009) and Abd Allah et al., (2010).
The interaction
Figure (5) showed that, the root length significantly affected
positively by conventional tillage compared with no tillage (AxB) in both
seasons of study. Where, the longest root (27.86 cm) was obtained by
conventional tillage with irrigation every 4 days, while the lowest value of
root length (18.09 cm) was obtained by no tillage with irrigation every 8
days. Also, the conventional tillage was more effective on root length under
6 days in compared to 4 and 8 days irrigation regimes in 2012 season. It is
observed that, the root length increased under irrigation every 6 days from
24.46 cm with no tillage to 26.33 cm with conventional tillage. That may due
to the tilled soil was easier for root penetration particularly under moderate
water deficit in the soil, but under high water deficit or drought condition, the
root growth affected negatively. These findings are in agreement with those
obtained by Wan et al., (2009).
systems (B) for root length in 2012 season.
In addition, root length was significantly differed by the interaction
between irrigation regimes and rice cultivars (AxC) in both seasons. Figure
(6) showed that Hybrid 1 was significantly surpassed the other rice cultivars
in root length under the three irrigation regimes where, recorded the longest
roots (33.27 and 33.43 cm) under irrigation every 4 days in 2011 and 2012
NT CT
4 Days 26.91 27.86
6 Days 24.46 26.33
8 Days 18.09 19.58
Root Length (cm)
2012
LSD 0.05 = 0.42

34
seasons, respectively. While the shortest roots (16.12 and 16.54 cm) was
obtained by Sakha 104 under irrigation every 8 days in 2011 and 2012
seasons, respectively. Giza 178 significantly surpassed Sakha 101 and Sakha
104 under all irrigation regimes in both growing seasons. These results
agreed with those reported by Gaballah, (2009) and Abd Allah et al.,
(2010). On the other side, both first order interaction (BxC) and second order
interaction among three factors didn't reveal any significance for root length
in both seasons of study.
cultivars (C) for root length (cm) in 2011 and 2012 seasons.
3- Root/shoot ratio
Data in Table (2) showed root/shoot ratio as influenced by irrigation
Root/shoot ratio had highly significant differences as affected by
different irrigation regimes in the two seasons of study. Results in Table (2)
showed significant variations in the root/shoot ratio, where the highest
root/shoot ratios (0.703 and 0.702) were found when the rice plants irrigated
every 4 days, followed by (0.697 and 0.702) measured in 6 days irrigation
H 1 33.27 30.79 22.29
Giza 178 28.08 25.93 19.47
Sakha 104 23.73 21.66 16.12
Sakha 101 24.91 22.60 16.88
Root Length (cm)
2011
LSD 0.01 = 1.28
H 1 33.43 31.12 22.54
Giza 178 28.24 26.01 19.30
Sakha 104 23.46 21.92 16.54
Sakha 101 24.41 22.53 16.96
Root Length (cm)
2012
LSD 0.01 = 1.10

35
regime in 2011 and 2012 seasons, respectively. However, there were no
significant differences were observed between 4 and 6 days irrigation
regimes in 2012 season. On the opposite, the lowest root/shoot ratios (0.641
and 0.649) were measured at 8 days irrigation regime in 2011 and 2012
seasons, respectively. These findings agree with the fact that rice grown
under drought conditions normally has slower growth than that growth under
agreement with those obtained by Kondo et al., (2003) and Gaballah (2009)
B) Tillage systems
In addition, results presented in Table (2) revealed that root/shoot
ratio was significantly affected by different tillage systems. The highest
root/shoot ratios were obtained under conventional tillage which ranged
between 0.684 and 0.688 in 2011 and 2012 seasons, respectively. While, the
lowest values of root/shoot ratio were found when rice plants were
transplanted in untilled soil (0.676 and 0.681) in 2011 and 2012 seasons,
respectively. These results led to conclude that the conventional tillage
caused successive improvement of soil structure which permitted to compose
bigger root system and also better shoot growth. Under no tillage,
accumulation of organic matter and nutrients such as N at or near the soil
surface restricts N-mineralization rate in the soil (Chamen and Parkin
1995). In addition, the maximum N-mineralization rate was observed in the
tilled soil, whereas in no tillage either alone or in combination of residue
retention the rate of N-mineralization rate decreased compared to
conventional tillage (Kushwaha et al., 2000). That may be decrease N-
uptake by rice plants, which negatively effect on plant growth and
development.
C) Rice cultivars
In addition, Table (2) showed that rice cultivars had highly significant
effects on root/shoot ratio in 2011 and 2012 seasons. The highest values of
root/shoot ratio were obtained by Hybrid 1 (0.720 and 0.725) followed by
Giza 178 (0.707 and 0.713) in both seasons. While, the lowest values of
root/shoot ratio were obtained by Sakha 104 rice cultivar (0.622 and 0.628) in
2011 and 2012 seasons, respectively. The different performance for the rice

36
cultivars under study may be due to genetic variations among cultivars. These
findings agree with Gaballah (2009)
The interaction
cultivars (C) for root/shoot ratio in 2011 and 2012 seasons.
The interaction between irrigation regimes and rice cultivars (AxC)
had highly significant effect on root/shoot ratio in both seasons. Figure (7)
showed that, Hybrid 1 recorded the highest values of root/shoot ratio (0.727
and 0.733) under 6 irrigation regime in 2011 and 2012 seasons, respectively.
On the other hand, Sakha 104 was severely affected under 8 days irrigation
regimes compared with the other irrigation regimes, where; the lowest
root/shoot ratio (0.508 and 0.522) was obtained by Sakha 104 under 8 days
irrigation regimes in 2011 and 2012 seasons, respectively. Since drought
occurs when there is an imbalance between water absorption and
transpiration, greater root growth can help the plant perform better under
a limited water supply. Under drought conditions, the soil starts drying from
the surface but the deep soil horizon may remain wet and able to supply
water to the plant’s roots. Consequently, deep root portions may be more
meaningful than shallow root portions, when the drought resistance of a
variety is to be examined. For this reason, the root-shoot ratio is considered
a better measure for drought resistance in the field. Hence, Sakha 101 and
H 1 0.722 0.727 0.712
Giza 178 0.712 0.710 0.702
Sakha 104 0.688 0.672 0.508
Sakha 101 0.693 0.678 0.642
Root/Shoot Ratio
2011LSD 0.01 = 0.014
H 1 0.723 0.733 0.718
Giza 178 0.713 0.718 0.708
Sakha 104 0.687 0.675 0.522
Sakha 101 0.688 0.682 0.648
Root/Shoot Ratio
2012LSD 0.01 = 0.012

37
Sakha 104 as Japonica rice cultivars were severely affected by the drought as
compared with Giza 178 as Indica-Japonica type and the hybrid rice cultivar
(Hybrid 1) in the two seasons of study. These results may be explaining the
reason behind high yield shortage in the two japonica cultivars (Sakha 101
and Sakha 104) under drought condition (8 days). These findings are in
agreement with those obtained by Yoshida (1981).
4-Number of days to 50% heading (days)
Data in Table (3) showed number of days to heading as influenced by
Data in Table (3) indicated that, there are highly significant
differences among irrigation regimes on heading date in both seasons, where
irrigation every 8 days delayed heading date up to (110.71 and 110.33 days)
while irrigation every 4 days recorded the shortest period (105.75 and 105.25
days) from sowing to 50 % heading in 2011 and 2012 seasons respectively.
The delay in flowering under drought is a consequence of a reduction in plant
dry-matter production and of a delay in panicle exsertion. These results
agreed with those obtained by Murty and Ramakrishnayya (1982) and El-
Refaee (2012). In addition, Novero et al., (1985) reported that the delay in
flowering depends on the intensity, time, and period of drought. Wopereis et
al., (1996) observed longer flowering delay when drought occurred during
early tillering than when it occurred in mid-tillering stage. Also, Pantuwan
et al., (2002) mentioned similar observations and concluded that under
prolonged drought, flowering time is an important determinant of rice grain
yield. The maturation stage, which is regarded as the period between anthesis
and harvest, is also delayed as a result of delayed flowering or when drought
appears after flowering.
B) Tillage systems
The tillage systems showed significant effect on days to heading in
2011 season and highly significant effect in 2012 season, where conventional
tillage recorded the shortest period (107.89 and 107.64 days) whereas no

38
tillage delayed heading date up to (108.53 and 108.11days) in 2011 and 2012
seasons respectively. As it was discussed previously, the tilled soil allowed
composing better and deeper root system, which helped the rice plants to
grow and develop properly, in addition to alleviate the drought stress which
increase the plant dry-matter production and accelerate panicle exsertion.
C) Rice cultivars
The effect of rice cultivars showed highly significant differences on
days to heading in both seasons. The longest periods from sowing up to 50 %
heading (114.00 and 114.00 days) were recorded by Sakha101 rice cultivar
however Sakha 104 rice cultivar recorded the shortest period (103.83 and
103.28 days) in 2011 and 2012 seasons, respectively. These results may be
due to the varietal differences and genetic characters of each genotype.
Marie-Noëlle et al., (2010) concluded that, the observed differences among
genotypes in the delays might be a result of differences in plant water status
in the genotypes during the drought and consequently in the drought escape
and avoidance potential of the genotypes.

39
Table (3): Effect of irrigation regimes (A), tillage systems (B), rice cultivars (C) and
their interactions on days to heading (days), plant height (cm) and flag leaf area
(cm2
) of Egyptian Hybrid 1, Giza 178, Sakha 104 and Sakha 101 rice cultivars in
2011 and 2012 seasons.
Days to heading
(days)
Plant height cm. Flag leaf area cm2
2011 2012 2011 2012 2011 2012
A - Irrig. Regimes
a1 - 4 Days
a2 - 6 Days
a3 - 8 Days
105.75 c
108.17 b
110.71 a
105.25 c
108.04 b
110.33 a
105.08 a
99.17 b
91.00 c
106.08 a
100.04 b
93.00 c
30.46 a
29.31 b
21.56 c
30.58 a
29.51 b
21.72 c
Ftest ** ** ** ** ** **
L.S.D0.05
L.S.D0.01
-
0.86
-
1.17
-
3.84
-
3.58
-
0.60
-
0.45
B- Tillage systems
b1 – Conventional tillage
b2 – No tillage
107.89 b
108.53 a
107.64 b
108.11 a
99.08 a
97.75 b
100.42 a
99.00 b
27.29 a
26.93 b
27.47 a
27.07 b
Ftest * ** ** ** ** **
L.S.D0.05
L.S.D0.01
0.47
-
-
0.46
-
1.22
-
1.24
-
0.28
-
0.37
C- Rice cultivars
c1 - Hybrid 1
c2 - Giza 178
c3 - Sakha 104
c4 - Sakha 101
107.22 b
107.78 b
103.83 c
114.00 a
107.00 b
107.22 b
103.28 c
114.00 a
103.67 a
94.94 b
105.83 a
89.22 c
105.17 a
96.72 b
106.61 a
90.33 c
29.90 a
28.69 b
25.06 c
24.79 c
30.03 a
28.87 b
25.22 c
24.97 c
Ftest ** ** ** ** ** **
L.S.D0.05
L.S.D0.01
-
0.73
-
0.78
-
2.90
-
2.48
-
0.43
-
0.48
Interaction:
Ftest (A × B)
Ftest (A × C)
Ftest (B × C)
Ftest (A × B × C)
NS
*
NS
NS
NS
NS
NS
NS
*
**
NS
NS
*
**
NS
NS
*
**
NS
NS
*
*
NS
NS
(NS) = Not Significant, (*) = Significant at 0.05 and (**) = Significant at 0.01 level of
probability.
Means followed by the same letters are not significant.

41
The interaction
The interaction effect between irrigation regimes and rice cultivars
(AxC) on number of days to heading was significant in the first season,
while, no significant effect was found in the second season. Figure (8)
showed that, the longest period was recorded by Sakha 101 (116.67 days)
when the plants were irrigated every 8 days but the shortest period was
recorded by Sakha 104 (100.67 days) under 4 days irrigation regime in 2011
growing season. That may be due to, the vegetative growth stage is prolonged
under drought stress compared with normal condition, which delay the
heading date, particularly Sakha 101 which has longer vegetative growth
duration.
Figure (8): The interaction between irrigation regimes (A) rice
cultivars (C) for days to heading in 2011 season.
5- Plant height (cm)
Data in Table (3) showed plant height (cm) as influenced by
The effect of irrigation regimes on plant height (cm) was highly
significant in the two seasons of study. Table (3) showed that, irrigation
every 4 days recorded the highest values (105.08 and 106.08 cm), followed
H 1 105.33 107.33 109.00
Giza 178 105.33 107.67 110.33
Sakha 104 100.67 104.00 106.83
Sakha 101 111.67 113.67 116.67
Days to heading
2011
LSD 0.05 = 0.95

41
by irrigation every 6 days (99.17 and 100.04 cm). On the contrary, irrigation
every 8 days recorded the lowest values (93.00 and 91.00 cm) of plant height
in 2011 and 2012 seasons, respectively. These results may be attributed to the
significant effect of water in encouraging cell turgor and elongation. Further,
under drought, plant development is reduced as a consequence of (a) poor
root development; (b) reduced leaf-surface traits (form, shape, composition of
cuticular and epicuticular wax, leaf pubescence, and leaf color), which affect
the radiation load on the leaf canopy; (c) delay in or reduced rate of normal
plant senescence as it approaches maturity; and (d) inhibition of length or
division of stem cells. These results agreed with those obtained by Blum
(2002), Gewaily (2006), El-Agamy, et al., (2007) and Ndjiondjop et al.,
(2010).
B) Tillage systems
Data in Table (3) showed highly significant effect of the two tillage
systems on plant height (cm). The tallest plants were recorded under
conventional tillage (99.08 and 100.42 cm), while the shortest plants (97.75
and 99.00 cm) were obtained under no tillage in 2011 and 2012 seasons,
respectively. These findings could be attributed to the ability of tillage to
improve soil conditions that enhance the growth of rice plants due to the root
volume which is affected positively by the conventional tillage. In no tillage
accumulation of organic matter and nutrients such as N at or near the soil
surface restricts N-mineralization rate in the soil. As a result, N-uptake by
rice plants decreased, which negatively effect on plant growth and
development. These findings are in harmony with those obtained by Chamen
and Parkin (1995).
C) Rice cultivars
Regarding rice cultivars performance, highly significant differences
were observed in plant height among the four rice cultivars under study in
both seasons. Sakha 104 recorded the highest values (105.83 and 106.61 cm)
followed by Hybrid 1 (103.67 and 105.17 cm) without significant differences
in 2011 and 2012 seasons, respectively. On the contrary, Sakha 101 revealed
the lowest values (89.22 and 90.33 cm) in 2011 and 2012 seasons,

42
respectively. These results could be due to the genetic differences of the rice
cultivars. These results are in harmony with those obtained by Mousa (2008).
The interaction
systems (B) for plant height (cm) in 2011 and 2012 seasons.
The interaction between irrigation regimes and tillage systems (AxB)
significantly effected on plant height in 2011 and 2012 seasons (Figure 9).
Where, both tillage systems gave the highest values (105.08 and 106.08 cm)
under irrigation every four days, in both seasons, respectively. On the other
hand, no tillage recorded the lowest values of plant height (89.58 and 91.58
cm) under 8 days irrigation regime in both seasons, respectively. The results
showed that, no tillage under drought conditions produced small root volume,
which caused inhibition of length or division of stem cells.
Figure (10) showed the interaction between irrigation regimes and
rice cultivars (AxC) was highly significant for plant height (cm) in both
seasons where it could be noticed that, Sakha 104 under irrigation every 4
days recorded the highest values of plant height (114.00 and 115.00 cm)
whereas irrigation every 8 days with Sakha 101 gave the lowest value (81.00
and 83.00 cm) in 2011 and 2012 seasons, respectively. These results showed
different varietal response to drought stress, where; Sakha 104 severely
affected under irrigation every 8 days compared to other cultivars under
NT 105.08 98.58 89.58
CT 105.08 99.75 92.42
Plant height (cm)
2011LSD 0.05 = 1.39
NT 106.08 99.33 91.58
CT 106.08 100.75 94.42
Plant height (cm)
2012LSD 0.05 = 1.42

43
study. That may be due to the ability of each cultivar to produce deeper root
and absorb more water under water deficit. These results are in harmony with
those obtained by El-Kady and Draz (1995), El Wehishy and Abd El
Hafez (1997) and Gewaily (2006).
cultivars (C) for plant height (cm) in 2011 and 2012 seasons.
)
Data in Table (3) showed flag leaf area as influenced by irrigation
Highly significant differences among the mean values of flag leaf area
(cm2
) were estimated in both seasons as affected by different irrigation
regimes. Data in Table (3) showed that, irrigation every 4 days recorded the
highest values (30.46 and 30.58 cm2
), while; irrigation every 8 days recorded
the lowest values (21.56 and 21.72 cm2
) in 2011 and 2012 seasons,
respectively. These results could be due to effect of water on activation the
cell division and elongation, which in turn decreases shoots enlargement
under water deficit. These findings are in agreement with those obtained by
H 1 109.67 105.17 96.17
Giza 178 99.00 92.67 93.17
Sakha 104 114.00 109.83 93.67
Sakha 101 97.67 89.00 81.00
Plant height (cm)
2011
LSD 0.01 = 5.02
H 1 110.67 106.67 98.17
Giza 178 100.00 95.00 95.17
Sakha 104 115.00 109.17 95.67
Sakha 101 98.67 89.33 83.00
Plant height (cm)
2012
LSD 0.01 = 4.29

44
El-Kady and Draz (1995), El Wehishy and Abd El Hafez (1997) and
Gewaily (2006).
B) Tillage systems
In addition, highly significant differences between the mean values of
flag leaf area (cm2
) were estimated in both seasons as affected by different
tillage systems. Data in Table (3) showed that, conventional tillage recorded
the highest values (27.29 and 27.47 cm2
) whereas; no tillage revealed the
lowest values (26.93 and 27.07cm2
) in 2011 and 2012 seasons, respectively.
Since conventional tillage resulted significant increase in root volume and
length, dry matter content increased which led to increase flag leaf area.
C) Rice cultivars
Obviously, data in Table (3) illustrated highly significant differences
in flag leaf area (cm2
) among Hybrid 1, Giza 178 and both Sakha 104 and
Sakha 101 rice cultivars while, no significant differences were observed
between the last two rice cultivars in both seasons. Where, the largest values
of flag leaf area (29.90 and 30.03 cm2
) were recorded by Hybrid 1 followed
by Giza 178 (28.69 and 28.87 cm2
). On the contrary, the lowest values of flag
leaf area were obtained by Sakha 101 (24.79 and 24.97 cm2
) in 2011 and
2012 seasons, respectively. The observed significant differences in flag leaf
area among the four rice cultivars were mainly due to genetic variation
among rice cultivars.
The interaction
In addition, Flag leaf area was significantly affected by the interaction
between irrigation regimes and tillage systems (AxB) in both seasons of
study. As it is shown in Figure (11), conventional tillage (CT) significantly
increased the mean values of flag leaf area under both 6 and 8 irrigation
regimes compared with no tillage (NT), while no significant differences were
found between conventional and no tillage systems under continuous flooded
conditions (4 days irrigation regimes). Hence the highest values of flag leaf
area (30.51 and 30.59 cm2
) were recorded by no tillage, followed by

Evaluation of some rice cultivars under different water regimes and tillage systems PhD

Evaluation of some rice cultivars under different water regimes and tillage systems PhD

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