Wheat (Triticum aestivum L.) is the major and essential grain crop in
the world especially in Egypt because it is the stable food of the Egyptian
people. Wheat production represent a special position in agricultural policies
it is grown in Egypt on an area of 2.92 million faddan (4200 m2)
with an annual production of about 8.2 million tones and with an average yield
of 2.65 tons faddan-1 during the year 2009-2010 growing season (CLAC,
2011). Locations and seasons play a distinct role in respect to yield and
quality of wheat varieties (Aslani and Mehrvar, 2012).
Increase concentrations of greenhouse gases will result in a continuous increase
in earths temperatures and this increase could significantly impact wheat
plant life, productivity and grain quality. Abdullah et
al. (2007) found that a small endosperm, lower grain weightwere accompanied
to the raising intemperature in the post anthesis period of late sown as a result
to shortened the grain filling period however and increased crude protein content.
Therefore it is very important to the choice of the suitable sowing date and
there are enough possibilities to increase wheat yields through developing new
high yielding varieties and by adopting proper sowing date. Therefore, the sowing
date and genotype are the most important factor that affects grain quality.
The optimum sowing date of wheat cultivars lead to increase 1000-grain weight
(Ali et al., 2010) and test weight, grain protein
content as well as wet and dry gluten content (Jie et
al., 2005). Zhu and Khan (2001) declared that
protein and its quality traits were substantially affected by genotype, environment
and their interaction. Motzo et al. (2007) indicated
that the environmental condition pertaining befor and during grain filling greatly
affecting quality of whea and can therefore be modified by manipulation of cultivar
and sowing date. A delay in sowing date was associated with a decrease in main
grain weight but not in grain nitrogen content, thus leading to an overall increase
of crude protein percentage. The observed increase in protein% partially explained
the smaller gluten index. Moreover, they suggested that temperature above 30°C
at the end of the grain filling period has a negative effect on the gluten polymerization
Therefore, the target of the present study was to evaluate some grain chemical
and technological properties of three wheat cultivars at five sowing dates.
MATERIALS AND METHODS
Two field experiments were carried out in Agric. Expt. Farm, Fac. of Agric.,
Ain Shams Univ. at Shalakan, Kalubia Governorate, Egypt during 2010/2011 and
2011/2012 growing seasons to study the response of some bread wheat cultivars
to sowing dates. Each experiment included 15 treatments which were the combination
between three wheat cultivars namely (Sakha 93, Giza 168 and Gemmiza 9) which
were obtained from Wheat Dept., Agric. Res. Center (ARC), Ministry of Agric.
at Giza and five sowing dates which were: 1st October, 16th October, 1st November,
16th November and 1st December.
The mineral nitrogen fertilizer was applied as ammonium nitrate (33.5% N) at
a rate of 80 kg N fad-1. The N fertilizer was added in two equal
portions. The first portion was added just before the first irrigation and the
second portion was added just before the second irrigation. Phosphorus fertilizer
was applied as calcium super-phosphate (15.5% P2O5) at
a rate of 31 kg P2O5 fad-1 before sowing during
the preparation of the experimental soil.
The experimental design was split plot design in 6-replication. The sowing
dates were arranged in the main plot. Cultivars were allocated in the sub plots.
The experimental unit area was 14 m2 consisting of 20 rows each of
3.5 m in length and 20 cm apart, grains were drilled in a single row. The normal
practical applications of growing wheat cultivar were applied.
At harvest a random sample of 1 m2 of each treatment in three replications
was chosen, dried at 105°C and the following data were recorded.
Grain chemical composition: About 100 g of grains or straw from each
treatment in two replications were grounded and followed by fine grinding into
fine powder for chemical analysis. Total nitrogen content was estimated using
micro-Kjeldahl apparatus. The Grain Crude Protein Content (GCPC) was calculated
by multiplying the total nitrogen percentage by 5.7. Reducing, none reducing
and total sugars were determined according to Shaffer and Hartmann. The procedures
were carried out according to AOAC (1995) and the data
were calculated as percentage on dry matter basis at 105°C.
Wet and dry gluten were determined in fine air dried grains by hand-washing
the meal according to the standard method of Pleshkof (1976)
until starch was not detected in the washing water, then dried and weighed.
Wet and dry gluten were calculated as percentage of air dry grains. The hydration
capacity of gluten was calculated as follows:
Statistical analysis: Data of the 3-replication were computed for proper
statistical analysis according to SAS (2003). The LSD
at 5% level of significance was used to differentiate between means. Data of
2009/2010 and 2010/2011 growing seasons were subjected to homogeneity variance
test for running the combined analysis of the data.
RESULTS AND DISCUSSION
Varietal differences: Data cleared in Table 1 indicate
that wheat variety Gemmiza 9 had significant highest Grain Crude Protein Content
(GCPC) exhibiting 13.3%. Wheat varieties Giza168 and Sakha 93 were in the second
and third orders being 12.7 and 12.9%, respectively with slight differences
between them. The superiority of Gemmiza 9 may be due to higher rate of translocation
of nitrogenous compounds from source to sink comparing to other studied cultivars.
This finding could be attributed to genetic make-up of the cultivar and its
tolerance to high temperature during grain filling period. Data of reducing
and non reducing sugars as well as total minerals absorbed and translocated
to the sink for all studied varieties were insignificantly differed ranged between
0.15 to 0.17, 0.16 to 0.19 and 1.6 to 1.8% for the above respective traits.
Subsequently the total sugars were slightly differed ranging between 0.32 to
It means that the genetic make-up of wheat cultivar Gemmiza 9 was more adapted
to grow under the environmental conditions of Kaluobia governorate. Increase
protein storage in grains cultivar Gemmiza 9 might be attributed to improving
the efficiency of nitrogen utilization. This could be achieved through either
higher nitrogen uptake capacity of root system and/or through greater mobilization
of nitrogenous compounds from the vegetative organs to the grains. This observation
was close with that obtained by Motzo et al. (2007).
Data in Table 2 revealed that the studied wheat cultivars
were significantly differed in their quality characters. Gemmiza 9 produced
the highest test weight, weight of unit volume, 1000-grain weight, wet and dry
gluten as well as gluten hydration percentage exhibiting 827.0 g L-1,
52.2 g, 28.0, 10.4 and 167.5%, respectively. A slight difference was noticed
between Gemmiza 9 and Giza 168 in test weight dry gluten percentage. Also there
was no significant difference between Gemmiza 9 and Sakha 93 in gluten hydration.
||Varietal differences in some biochemical properties (% on
dry matter basis) of wheat grain. Combined analysis of the two growing seasons
||Varietal differences in some technological properties of wheat
grain. Combined analysis of the two growing seasons
The differences in quality of studied cultivars might be attributed to their
genetic make-up. These results are coincided with those of Shahzad
et al. (2002, 2007). From the above data
in Tables 1 and 2 it was cleared a positive
relationship between GCPC, vitreosness wet gluten content; test weight and 1000-grain
This observation was agreed with that reported by Motzo
et al. (2007).
Effect of sowing date: The data of chemical composition of wheat grains
versus sowing dates were also studied and the data are shown in Table
3. The data assumed that reducing, none reducing and ash content of wheat
grains did not significantly affect versus late or early sowing dates, i.e.,
from 1st October up to 1st December. Their values ranged from 0.1 to 0.2% for
each of reducing and none reducing sugars as well as, 0.3 to 0.4% for total
sugars; 1.7% for Ash content. From the other side, the GCPC was gradually and
markedly decreased from 13.7% at early sowing date on 1st October up to 16th
November being 12.5%. This finding could be explained that, at earlier sowing,
wheat plants removed more N from the soil than in optimum or late sowing. Therefore,
the mean GCPC was higher by early sowing (Abdullah et
al., 2007). Thereafter, delaying sowing date to 1st December accompanied
with substantial increase in crude protein content reaching 12.9%.
Regarding the effect of sowing date on some technological properties of wheat
grains, the data of the studied traits are shown in Table 4.
Data revealed that test weight was significantly and gradually increased versus
sowing date of wheat till reached its maximum value by sowing on 1st November
which produced significantly larger grains (824.0 g L-1) and higher
1000-grain weight (52.2 g) comparing to sowing early or late in the season.
It was also cleared from Table 4 that late sowing date in
the season was corresponded with significant decrease of grain vitreosness,
wet and dry gluten percentage. The effect of sowing date on grain quality was
in accordance with Shahzad et al. (2002), Aslam
et al. (2003) and Yan et al. (2008).
||Some technological properties of wheat grain as affected by
sowing dates. Combined analysis of the two growing seasons
||Effect of the interaction between wheat cultivars and sowing
dates on some biochemical properties (% on dry matter basis) of wheat grains.
Combined analysis of the two growing seasons
||Effect of the interaction between wheat cultivars and sowing
dates on some technological properties of wheat grains. Combined analysis
of the two growing seasons
Effect of the interaction between wheat cultivars and sowing dates:
The data in Table 5 indicate clearly that the effect of the
interaction between sowing dates and wheat cultivars was found to be non significant
in the all biological traits. Concerning GCPC it was found that th highest value
was obtained by early sowing on 1st October. Delay sowing date up to 1st November
was accompanied with increase of GCPC. It was also noticed that grains of wheat
cultivar Gemmiza 9 is characterized by higher GCPC (14.1%).
The interaction between wheat cultivars and sowing dates on techno-logical
quality properties were studied and the data are shown in Table
6. The data cleared that test weight, 1000-grain weight and vitreosness
were significantly varied among cultivars and sowing dates. Wheat cultivar Gemmiza
9 exhibited the highest value of test weight on 1st November being 850 g L-1,
1000-grain weight (53.9 g) and vitreosness (53.5%). In addition, delaying sowing
date had positive effect on test weight and negative effect on 1000-grain weight