Effect of Sulphur Fertilization on Breadmaking Quality of Three Winter Wheat Varieties
For study of the effect of sulphur and nitrogen on breadmaking
quality of three varieties of wheat, four field experiments were carried
out at four sites in north and northeast of Iran. This research carried
out as factorial experiment based on randomized complete block design
with three factors and four replications. Factors to be studied were,
wheat varieties of Tajan, Falat, Sardari and sulphur at the rate of 0,
20 and 80 kg ha-1 in the form of gypsum and nitrogen at two
rate of 180 and 230 kg ha-1 in the form of urea. Results showed
that sulphur increased the loaf volume significantly and decreased the
N:S ratio in grain. Grain S concentration had high correlation coefficient
with grain protein percent. Sulphur increment caused increase in loaf
volume, better breadmaking quality, which may be due to gluten in protein.
Nitrogen fertilizer application increased protein concentration of grain,
but it had no significant effect on loaf volume.
It has been established that the sulphur (S) nutrition of wheat has an
important influence on the breadmaking quality of flour (Thomason et
al., 2007). This is due to the essential role of disulphide bonds
in maintaining gluten functionally in flour (Shewry and Tarham, 1997).
Although the essential role of S for plant growth and development has
long been recognized, deficiency of S in agricultural crops was rare in
world until about a decade ago. A considerable decrease in the inputs
of S from atmospheric deposition since the early 1970s, coupled with increased
crop yields and a change from the use of S-containing fertilizers to S-free
fertilizers, has contribute to increased S deficiency over the last decade
(Zhao et al., 1999a). Cereal crops require only a moderates amount
of S (15-20 kg ha-1) for optimum growth, although yield increases
in response to the addition of S fertilizers have been reported by Zhao
et al. (1999a). In the future the need for S fertilizers is predicted
to increase as atmospheric deposition of S is likely to decrease further
in industrialized countries (Al-Eid, 2006; Shewry and Tarham, 1997). In
wheat, deficiency of S can result not only in yield decreases, but also
in low breadmaking quality. In the 1980s Australian researchers demonstrated
that S deficiency in wheat had a profound effect on the composition of
gluten proteins in wheat grain, with increased synthesis of S-poor proteins
(ω-gliadins and High-Molecular-Weight (HMW) subunits of glutenin)
at the expense of S-rich proteins (z-and y-gliadins and low-molecular-weight)
(LMW) subunits of glutenin (Shewry and Tarham, 1997; Fullington et
al., 1987; Tea et al., 2004; Lerner et al., 2006; Mason
et al., 2007; Thomason et al., 2007). These compositional
changes were associated with decreased extensibility and increased elasticity
of dough. Field experiments conducted in England before 1990 showed that
breadmaking quality, as measured by loaf volume, was not affected significantly
by the applications of S fertilizers (Salmon et al., 1990; Kettelwell
et al., 1998), probably because S deficiency was rare at that time.
Grain protein content is the most commonly studied parameter of wheat
quality (Mason et al., 2007).
However, there was some evidence that when a large amount of nitrogen
(N) was applied late to wheat, the quality of gluten proteins for breadmaking
deteriorated owing to an imbalance of N and S (Al-Eid, 2006; Timms et
al., 1981). It is important that the effect of S nutrition on the
breadmaking quality of field-grown wheat are fully understood. Several
recent reports suggest that environmental conditions could quantitatively
affect storage protein components (Al-Eid, 2006).
This research forms part of a systematic study to evaluate the responses
of breadmaking quality parameters of winter wheat to the addition of S
fertilizer under field conditions in the major wheat-growing area of north
and northeastern of Iran. This study further compares the responses of
three breadmaking wheat varieties to S application in field experiments.
MATERIALS AND METHODS
Field experiments condition: Four field experiments were conducted
during 2002-2003 growing season at two sites in Golestan and two sites
in Khorasan provinces. Soil properties at each experimental site are shown
in Table 1. Soil samples were collected from 0-30 and
30-60 cm depth in early autumn prior to fertilizer application. There
were 18 treatments in each experiment, consisting of all factorial combinations
of three varieties of winter wheat (Triticum aestivum L.), the
varieties included Tajan, Falat and Sardari, three S levels (0, 20 and
80 kg ha-1 in the form of gypsum) and two N levels (180 and
230 kg ha-1 in the form of urea). Urea applied in two splitting
and gypsum applied in spring at anthesis stage. All experiments were conducted
as factorial based on randomized complete block design with four replications.
Fungicides and pesticides applied according to standard practices whenever
needed. Plot size were 30 m2 at each plot at different sites.
At maturity, crops were harvested using one square meter quadrate with
three replications from each plot. About 5 kg of grain from each plot
was used for the determination of bread making quality parameter. Grains
were dried at 80°C for 16 h and milled and passed through 0.5 mm sieve.
The concentration of N was determined titrimetrically after Kjeldahl digestion
with copper catalyst (Withers et al., 1995). For determination
of S, samples were digested with a mixture of HNO3 and HClO4
(Zhao et al., 1994) followed by measurement of S in solution using
spectrophotometer (Massoumi and Cornfield, 1963). The concentration of
N and S are expressed on a dry matter basis, whereas grain protein concentration
was calculated on an 86% dry matter basis. Grain N:S ratio was calculated
from the N and S concentrations.
Milling and breadmaking test: Grain samples were milled on a Buhler
MLU 202 mill to produce straight-run white flour. The additional flour
produced was blended with the straight-run white flour for quality testing.
The amount of gel protein in white flour and its elastic modulus were
determined by the method of Pritchard and Brock (1994). Flour (10 g) was
defatted with 25 mL of petroleum ether (at 40-60°C) for 1 h, filtered
and dried. Defatted flour (5 g) was stirred with 90 mL of 1.5% sodium
sulphate for 10 min at 10°C before being centrifuged at 4x104
g for 40 min. The protein was measured using a 10 mg protein dissolved
in 0.063 molar HCl in 6.8 and determined with HPLC. Sulphur extracted
concentration determined with spectrophotometer (Massoumi and Cornfield,
1963). Total S in soil determined using Butters and Chenery (1959). Analysis
of variance (ANOVA) was preformed on all data sets. Data from all sites
were combined in correlation and regression analysis. The statistical
package Minitab12 and Excel were used.
RESULTS AND DISCUSSION
Grain yield: Grain yields and crop S uptake data showed significant
(p<0.01) yield increase in response to S application at all sites (data
were not presented) but there were more response to S application in irrigated
fields of both provinces. Application of N and S significantly increased
flour production especially in Tajan in irrigated field of Golestan province
with 0.4% at 95% level (data were not shown). Soil physico-chemical properties
were presented in Table 1. The ANOVA results for all
flour parameters tested are shown in Table 2. It is
clear that the treatments effects varied between the four sites and interactions
between variety, S and N treatments were not significant except in four
cases (Table 2).
Grain protein, S concentration and N: S ratio: Results of this
study showed the effects of N treatment on grain protein percent and also
grain S concentration was significant (Table 2). Mean
concentrations of grain protein were 12.6, 12.5 and 12.2 for Tajan, Falat
and Sardari, respectively. Increasing the N rate from 180 to 230 kg ha-1
increased grain protein concentration significantly (Table
3), although the effect was much greater at irrigated farms than at
non-irrigated farms. Significant differences were observed between the
three varieties for above traits, in the order of Tajan>Falat>sardari
in Golestan irrigated fields. Application of S increased grain protein
concentration significantly with an average increase of 0.3% in both S20
and S80 over the S0 treatment (Table
2-4). There were significant differences between the three varieties
in the concentrations of S in grain (Table 2, 4,
5). Application of S increased grain S concentration
significantly at all fields, the response being much greater at irrigated
field of Golestan province. Increase the N rate also increased grain S
concentration. Grain N: S ratio was significantly affected by variety
and S treatments (Table 2).
Grain N: S ratio in plots received N and S fertilizes was below the 16
and Grain N: S ratio decreased significantly in other treatments compared
to control (Table 2). Significant mean differences between
varieties were found only in Sardari compare two other varieties (Table
3, 4). Loaf volume was increased significantly by
variety, S and N addition in all farms except GPNI in later case (Table
||Soil physical and chemical properties of study sites
GPI: Irrigated field of Golestan,
GPNI: Non-irrigated field of Golestan, KPI: Irrigated field of Khorasan,
KPNI: Non-irrigated field of Khorasan
||Levels of significance of treatment effects on grain
and flour properties and breadmaking quality of wheat
*Significant at 0.05% level, **Significant
at 0.01% level, ***Significant at 0.001% level, NS: Not Significant
|| Effect of S and N treatments on grain S concentration,
grain N: S ratio and some breadmaking quality of wheat fields of Golestan
The results showed application of S significantly increased the loaf
volume in all treatments, due to the fact that increased grain S concentration
cased greater grain protein (Al-Eid, 2006; Zhao et al., 1999b).
Application of S in early spring increased the grain S concentration which
decreased the grain N:S ratio in all as shown in (Table
5) sites especially in irrigated field of both provinces. Although
the effect of S on breadmaking quality is significant, but increased 50
kg ha-1 N application from 180 to 230 kg ha-1 has
no significant effect on breadmaking quality of the grain (Table
2). Apart from being an indicator of the quantity of protein in grain,
the S concentration also reflects the quality of proteins. This is demonstrated
by the profound influence of S nutrition on the concentration of gluten
proteins similar result were obtain by Al-Eid (2006) and Zhao et al.
(1999a). An imbalance of N and S in wheat grain, as indicated by a grain
N: S ratio of more than 16 in this study reflects the poor breadmaking
quality. A slightly higher critical N: S ratio of 17 was reported by Byers
et al. (1987).
||Effect of S and N treatments on grain S concentration,
grain N: S ratio and some breadmaking quality of wheat in fields of
The three varieties used in this study differed greatly in the properties
of gel protein and dough rheology. Tajan contain larger amounts of gel
protein than Falat and Sardari (data were not shown). Despite these differences,
the responses of loaf volume to S application were similar among all three
varieties at all sites. On average, there were some small differences
in loaf volume between the three varieties, but these differences were
not consistent at all sites.
Table 5 shows simple correlation coefficient between
grain S concentration, Grain N:S ratio, Grain protein percentage, Loaf
volume and grain gluten protein, using the whole data set of all varieties
pooled from the four sites. There were close and significant correlation
between S concentration of grain and grain protein percentage (Table
5). Because more than 90% of the total S in wheat grain is bound in
organic forms, mainly as protein (Byers et al., 1987), it is not
surprising that the concentration of S correlated strongly with grain
protein concentration. Positive correlations were observed between grain
S concentration and loaf volume and also with grain gluten protein (Table
In conclusion, an increase in grain S concentration in response to S
fertilization benefited the breadmaking quality of three wheat varieties,
whereas application of an extra 50 kg ha-1 N increased a little
grain protein concentration without improving breadmaking quality. This
study revealed that addition of S fertilizer is required in many wheat-growing
area of north and northeastern of Iran to maintain breadmaking quality.
Al-Eid, S.M., 2006. Effect of nitrogen and manure fertilizer on grain quality, baking and rheological properties of wheat grown in sandy soil. J. Sci. Food Agric., 86: 205-211.
Direct Link |
Butters, B. and E.M. Chenery, 1959. A rapid method for the determination of total sulphur in soils and plants. Analyst, 84: 239-245.
CrossRef | Direct Link |
Byers, M., S.P. McGrath and R. Webster, 1987. A survey of the sulphur content of wheat grown in Britain. J. Sci. Food Agric., 38: 151-166.
Fullington, J.G., D.M. Miskelly, C. Wwrigley and D.D. Kasarda, 1987. Quality-related endosperm proteins in sulphur-deficient and normal wheat grain. J. Cereal Sci., 5: 233-245.
Kettelwell, P.S., M.W. Griffiths, T.J. Hocking And D.J. Wallington, 1998. Dependence of wheat extensibility on flour sulphur and nitrogen concentrations and the influence of foliar-applied sulphur and nitrogen. J. Cereal Sci., 28: 15-23.
Lerner, S.E., M.L. Seghezzo, E.R. Molfese, N.R. Ponzio and M. Coglitti et al., 2006. N- and S-fertilizer effects on grain composition, industrial quality and end-use in durum wheat. J. Cereal Sci., 44: 2-11.
Direct Link |
Mason, H., H. Navabi, B. Frick, J. O’Donovan and D. Niziol et al., 2007. Dose growing canadioan western hard red spring wheat under organic management alter its breadmaking quality. Renewable Agric. Food Syst., 22: 157-167.
Direct Link |
Massoumi, A. and A.H. Cornfield, 1963. A rapid method for determination sulphate in water extracts of soils. Analyst, 88: 321-322.
Pritchard, P.E. and C.J. Brock, 1994. The gluten fraction of wheat protein: The importance of genetic background on its quantity and quality. J. Sci. Food Agric., 65: 401-406.
Salmon, S.E., P. Greenwell and P.M.R. Dampney, 1990. The effect of rate and timing of late nitrogen applications to breadmaking wheats as ammonium nitrate or foliar urea-N and the effect of foliar sulphur application. II. Effect on milling and baking quality. Aspects Applied Biol., 25: 242-253.
Shewry, P.R. and A.S. Tatham, 1997. Disulphide bonds in wheat gluten proteins. J. Cereal Sci., 25: 207-227.
Tea, I., T. Genter, N. Naulet, V. Boyer and M. Lummerzheim et al., 2004. Effect of foliar sulfur and nitrogen fertilization on wheat storage protein composition and dough mixing properties. Cereal Chem., 81: 759-766.
CrossRef | Direct Link |
Thomason, W.E., S.B. Phillips, T.H. Pridgen, J.C. Kenner and C.A. Griffey et al., 2007. Managing nitrogen and sulfur fertilization for improved bread wheat quality in humid environments. Cereal Chem., 84: 450-462.
CrossRef | Direct Link |
Timms, M.F., R.C. Bottomley, J.R.S. Ellis and J.D. Schofield, 1981. The baking quality and protein characteristics of a winter wheat grown at different levels of nitrogen fertilization. J. Sci. Food Agric., 32: 684-698.
Withers, P.J.A., A.R.J. Tytherleigh and F.M. O’Donnel, 1995. Effect of sulphur fertiliser on grain yield and sulphur content of cereals. J. Agric. Sci., 125: 317-324.
Zhao, F.J., M.J. Hawkesford and P.S. McGrath, 1999. Sulphur assimilation and effects on yield of wheat. J. Cereal Sci., 30: 1-17.
Zhao, F.J., S.E. Salmon, P.J.A. Withers, E.J. Evans and J.M. Monaghan et al., 1999. Responses of breadmaking quality to sulphur in three wheat varieties. J. Sci. Food Agric., 79: 1865-1874.
Zhao, F.J., S.P. McGrath and A.R. Crosland, 1994. Comparison of three wet digestion methods for the determination of plant sulphur by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Commun. Soil Sci. Plant Anal., 25: 407-418.