الفهرس 
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Abstract
The present investigation was carried out in 2009/2010 and 2010/2011 winter seasons at AL-Bostan Experimental Farm, Faculty of Agriculture, Dammanhour University, Egypt.
The main objectives of this study were:
1-To investigate the effects of drought stress on phenological development of eight bread wheat cultivars.
2-To study the end effects of drought stress on grain yield and its components of eight bread wheat cultivars.
3-To study the effects of drought stress on wheat quality traits.
The experiment was laid out in a split block arrangement in a randomized complete block design, with four replications, keeping irrigation levels in the main plots and genotypes in the sub-plots, in the two seasons of study.
Three different water treatments were applied in both seasons of study, as follows:
1-Normal irrigation. (T1).
3- Withholding irrigation from booting till full maturity (T2), (moderate stress).
4- Withholding irrigation from tillering till full maturity (T3), (severe water stress).
The experiments included eight bread wheat cultivars; namely, Sids 1, Sakha 61, Sakha 93, Sakha 94, Gemmeiza 7, Gemmeiza 9, Gemmeiza 10 and Giza 168.
The studied traits were as follows:
1- Number of days to anthesis.
2- Number of days to physiological maturity.
3- Grain fill duration (days).
4- Plant height (cm).
5- Number of spikes/m2.
6- Number of grains/spike.
7- Grain weight (mg).
8- Grain yield (ton/ha).
9- Crude protein (%).
10- Wet gluten (%).
11- Dry gluten (%).
12- Flour (%).
13- Fine bran (%).
14- Coarse bran (%).
15- Water absorption (%).
16- Arrival time (min).
17- Dough development time (min).
18- Dough stability time (min).
19- Dough weakness (B.U).
20- Dough resistance to extension (R).
21- Dough extensibility (E).
22- Proportional number.
23- The energy.
24- Sensory Properties of Shamy Bread.
The obtained results could be summarized as follows:
1-Plant phenology and grain development traits:
1.1- Number of days to anthesis:
In 2009/2010 season, the average number of days to anthesis was decreased from 88 days in normal irrigation (T1), to 87 days in the moderate irrigation (T2) and to 86.16 days, in the severe water stress (T3). In the second season (2010/2011), number of days to anthesis was decreased from 82.19 days, in normal irrigation (T1), to 81.34 days in the moderate irrigation (T2) and to 80.62 days in the severe water stress (T3).
In the first season, the earliest genotype, in anthesis, was Sakha61 where it recorded 81.42 days, while, the latest genotype, in anthesis, was Sids1, where, it recorded 92.58 days. In the second season, the earliest genotype, in anthesis, was Sakha61 where, it recorded 76 days, while, the latest genotype, in anthesis, was Gemmeiza 10, where it recorded 85 days.
1.2- Number of days to physiological maturity:
In 2009/ 2010 season, the average number of days to physiological maturity was decreased from 123.19 days, in normal irrigation (T1), to 117.94 days, in the moderate irrigation (T2) and to 106.59 days in the severe water stress (T3). In the second season (2010/2011) number of days to physiological maturity was decreased from 135.59 days, in normal irrigation (T1), to 130.72 days, in the moderate irrigation (T2) and to 124.43 days in the severe water stress (T3).
In the first season, the earliest genotype, in number of days to physiological maturity, was Sakha61 where it recorded 111.17 days, while, the latest genotype was Sakha 94, where it recorded 120.08 days. In the second season the earliest genotype, in number of days to physiological maturity, was Sakha61, where it recorded 126.17 days, while, the latest genotype was Gemmeiza 9, where it recorded 134.91 days.
1.3- Grain fill duration (GFD):
In 2009/2010 season, grain fill duration (GFD) was significantly decreased from 35.19 days, in normal irrigation (T1), to 30.94 days, in the moderate irrigation (T2) and to 20.44 days in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where grain fill duration was decreased from 53.31 days, in normal irrigation (T1) to 49.37 days in the moderate irrigation (T2) and to 43.87days in the severe water stress (T3).
The most high genotypes for GFD were Gemmeiza 7 and Gemmeiza 9, where, they recorded 32.42 and 50.92 days in the first and second seasons, respectively. On the other hand, the most low genotypes were Sids1 and Sakha 94, where, they recorded 23.25 and 45.25 days in the first and second seasons, respectively.
2- Plant height (cm):
In 2009/2010, plant height was significantly decreased from 92.91 cm, at normal irrigation (T1), to 82.97 cm, in the moderate irrigation (T2) and to 68.91 cm in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, plant height was significantly decreased from 91.25 cm at normal irrigation (T1), to 81.94 cm, in the moderate irrigation (T2) and to 70.19 cm in the severe water stress (T3).
The tallest genotype was Gemmeiza 9 in both seasons, where, it recorded 89.75 and 88.75 cm in the first and second seasons, respectively. On the other hand, the most short genotypes were Sakha 93 and Gemmeiza 10, where, they recorded 74.83 and 74.58 cm in the first and second seasons, respectively.
3-Grain yield and its components:
3.1- Number of spikes/m2:
In 2009/2010 season, such number was significantly decreased from 315.94 spikes/m2, at normal irrigation (T1), to 293.53 spikes/m2, in the moderate irrigation (T2), and to 220.44 spikes/m2 in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, the number of spikes/m2 was decreased from 333.59 spikes/m2, at normal irrigation (T1), to 300.47 spikes/m2, in the moderate irrigation (T2) and to 223.97 spikes/m2 in the severe water stress (T3).
The highest genotype, for such number of spikes/m2, was Sakha 93, where, it recorded 407.25 and 349.33 spikes/m2 in first and the second seasons, respectively. On the other hand, the lowest genotype was Giza 168, in the first season, while, Sakha 94 was the lowest genotype in the second season, which recorded 188.58 and 243.58 spikes/m2, respectively.
3.2- Number of grains/spike:
In 2009/2010 season, such number was significantly decreased from 70.86 grains/spike, at normal irrigation (T1), to 69.91 grains/spike, in the moderate irrigation (T2) and to 49.44 grains/spike in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, the number of grains/spike was decreased from 51.77 grains/spike, at normal irrigation (T1), to 47.29 grains/spike, in the moderate irrigation (T2) and to 38.99 grains/spike in the severe water stress (T3).
In 2009/2010, the highest genotype over all water levels, for number of grains/spike, was Sakha 93 (73.62), while, the lowest genotype was Giza 168 (52.41). In 2010/2011 season, the highest mean number of grains/spike was for Sakha 94, where, it had 52.93 grains/spike, while, the lowest number was Gemmeiza 7, where, it had 41.34 grains/spike.
3.3- Grain weight (mg):
In 2009/2010 season, grain weight was significantly decreased from 52.076 mg, at normal irrigation (T1), to 50.52 mg, in the moderate irrigation (T2) and to 38.53 mg in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, grain weight was significantly decreased from 52.65 mg, at normal irrigation (T1) to 47.69 mg, in the moderate irrigation (T2), and to 42.59 mg in the severe water stress (T3).
In 2009/2010, the highest genotype over all water levels, for grain weight was Sakha 93 (59.79 mg), while, the lowest genotype was Gemmeiza 10 (41.13 mg). In 2010/2011 season, the mot high mean of grain weight was for Sakha 61, where, it had 55.01 mg, while, the lowest was Sakha 93, where it had 43.01 mg.
3.4- Grain yield (tons/ha):
In 2009/2010 season, grain weight was significantly decreased from 6.39 tons/ha at normal irrigation (T1), to 6.01 tons/ha, in the moderate irrigation (T2) and to 2.86 tons/ha in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, grain yield was significantly decreased from 7.50 tons/ha at, normal irrigation (T1), to 6.34 tons/ha, in the moderate irrigation (T2), and to 4.57 tons/ha in the severe water stress (T3).
The most high genotypes over all water levels, for grain yield, were Sakha 93 and Gemmeiza 10, where, they recorded 7.04 and 7.39 tons/ha, in the first and second seasons, respectively. On the other hand, the most low genotypes were Giza 168 and Sakha 61, where, they recorded 4.08 and 4.28 tons/ha in the first and second seasons, respectively.
4-Wheat quality traits:
4.1- Crude protein (%)_:
In 2009/2010 season, P% was significantly increased from 9.56 %, at normal irrigation (T1), to 10.79%, in the moderate irrigation (T2) and to 12.45 % in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, P% was significantly increased from 9.93%, at normal irrigation (T1), to 10.68%, in the moderate irrigation (T2) and to 11.33% in the severe water stress (T3).
The most high genotypes over all water levels, for P% were, Gemmeiza 10 and Sakha 61, where, they recorded 11.52 and 11.68 % in the first and second seasons, respectively. On the other hand, the lowest genotype was Sakha 93, where, it recorded 9.99 and 9.81 % in the first and second seasons, respectively.
4.2- Wet gluten (%):
In 2009/2010 season, WG % was significantly increased from 24.85 %, at normal irrigation (T1), to 27.87 %, in the moderate irrigation (T2) and to 32.29 % in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, WG % was significantly increased from 25.77 %, at normal irrigation (T1), to 28 % in the moderate irrigation (T2) and to 30.14 % in the severe water stress (T3).
The most high genotypes over all water levels, for WG %, were Sids1 and Sakha 61, where, they recorded 30.92 and 30.89 % in the first and second seasons, respectively. On the other hand, the lowest genotype was Sakha 93, where, it recorded 24.3 and 23.125% in the first and second seasons, respectively.
4.3- Dry gluten (%):
In 2009/2010 season, DG % was significantly increased from 9.38 %, at normal irrigation (T1), to 11.71 %, in the moderate irrigation (T2) and to 14.05 % in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, DG % was significantly increased from 11.23%, at normal irrigation (T1), to 12.16 %, in the moderate irrigation (T2) and to 12.93% in the severe water stress (T3).
The most high genotypes over all water levels, for DG %, were Gemmeiza 10 and Gemmeiza 7, where, they recorded 12.76 and 13.45 % in the first and second seasons, respectively. On the other hand, the lowest genotype was Sakha 93, where, it recorded 10.35 and 10.36 % in the first and second seasons, respectively.
5- Milling characters:
5.1- Flour (%):
In 2009/2010 season, flour % was significantly decreased from 70.29 %, at normal irrigation (T1), to 65.57 %, in the moderate irrigation (T2) and to 58.68 % in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, flour % was significantly decreased from 65.66 %, at normal irrigation (T1), to 60.36 %, in the moderate irrigation (T2) and to 52.08 % in the severe water stress (T3).
The most high genotypes over all water levels, for flour %, were Sakha 93 and Gemmeiza 9, where, they recorded 70.94 and 64.96 % in the first and second seasons, respectively. On the other hand, the most lower genotypes were Gemmeiza 10 and Gemmeiza 7, where, they recorded 61.65 and 50.81 % in the first and second seasons, respectively.
5.2- Fine bran (%):
In 2009/2010 season, fine bran % was significantly increased from 7.37%, at normal irrigation (T1), to 9.79 %, in the moderate irrigation (T2) and to 12.27% in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, fine bran % was significantly increased from 7.09 %, at normal irrigation (T1), to 8.30%, in the moderate irrigation (T2) and to 11.82% in the severe water stress (T3).
The most high genotypes over all water levels, for fine bran %, were Gemmeiza 9 and Sakha 61, where, they recorded 10.48 and 10.44% in the first and second seasons, respectively. On the other hand, the lowest genotype was Sakha 93 and Gemmeiza 9, where, they recorded 8.57 and 6.88 % in the first and second seasons, respectively.
5.3- Coarse bran (%):
In 2009/2010 season, coarse bran % was significantly increased from 21.20 %, at normal irrigation (T1), to 23.37 %, in the moderate irrigation (T2) and to 27.75 % in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, coarse bran % was significantly increased from 23.70 %, at normal irrigation (T1), to 26.81 %, in the moderate irrigation (T2) and to 30.75 % in the severe water stress (T3).
The most high genotypes over all water levels, for coarse bran %, were Sids1 and Gemmeiza 7, where, they recorded 26.48 and 34.41 % in the first and second seasons, respectively. On the other hand, the lowest genotype was Sakha 93, where, it recorded 19.42 and 22.30 % in the first and second seasons, respectively.
5.4- Pollard (%):
In 2009/2010 season, pollard % was increased from 1.15 %, at normal irrigation (T1), to 1.29 %, in the moderate irrigation (T2) and to 1.30 % in the severe water stress (T3). Similar results were obtained in the second season (2010/2011), where, pollard % was significantly increased from 3.59 %, at normal irrigation (T1), to 4.57 %, in the moderate irrigation (T2) and to 5.34 % in the severe water stress (T3).
The highest genotype over all water levels, for pollard %, was Gemmeiza 10, where, it recorded 1.57 and 5.11 % in the first and second seasons, respectively. On the other hand, the lowest genotypes were Sakha 93 and Sakha 94, where, they recorded 1.06 and 3.53 % in the first and second seasons, respectively.
6- Rheological properties of dough:
Similar results were obtained in both seasons, where, most of the quality properties of farinograph; i.e., water absorption and dough-stability time, were improved with the declined water availability exception of dough weakness, which was negatively affected. Extensograph properties; i.e., dough resistance to extension and proportional number (dough resistance to extension/dough extensibility), were positively improved.
7- Sensory evaluation of Shamy bread:
The present results showed that the sensory properties of Shamy bread, prepared from stressed wheat flour, were slightly improved.