Art03_Erekul.indd Journal of Applied Botany and Food Quality 85, 17 - 22 (2012) 1Department of Crop Science, Adnan Menderes University, Aydin, Turkey 2Department of Crop and Animal Science, Humboldt-Universität zu Berlin, Berlin, Germany Effect of sulphur and nitrogen fertilization on bread-making quality of wheat (Triticum aestivum L.) varieties under Mediterranean climate conditions O. Erekul1, K.-P. Götz2, Y.O. Koca1 (Received November 18, 2011) Summary Turkey has applied for EU-membership, but still faces problems of lacking quality standards for bread wheat. Studies on the infl uence of S-fertilization on grain yield and bread-making quality of wheat (Triticum aestivum L.) in the region haven’t been carried out until today. This research was conducted for two growing seasons (2008- 2009 and 2009-2010) at Adnan Menderes University Research and Experimental Farm located in the Western Turkey (Aegean region) at 37º 44’ N 27º 44’ E in order to determine the effects of nitrogen (0, 70, 140, 210 kg ha-1) supplemented with sulphur (0 or 40 kg ha-1) with respect to yield and bread-making quality of the varieties Golia and Sagittario, grown primarily in Western Turkey. S-fertilization had positive effects on grain yield and some quality parameters under Mediterranean conditions; however, signifi cant differencess were rather rare. Particularly the gluten-index and the sedimentation value promoted by S fertilization were among the tested parameters. Therefore, S-fertilization in improving bread-making quality of wheat in the region should not be disregarded. Grain yield and quality could be promoted simultaneously with increasing N-doses. Introduction The area cultivated with wheat (Triticum spp. L.) has reduced in the last years in Turkey and today covers approximately 8.0 million ha (FAO, 2010). About 75% of the wheat produced in Turkey is bread wheat type. In the Aegean region of western Turkey, the wheat yield is mostly higher than the other wheat-cultivated areas (DINC and EREKUL, 2010). Despite the large extent of wheat cultivation in Turkey the locally produced wheat hardly achieved suffi cient yield and barely met the standards of food processing industry, thus high quality wheat has to be imported (EREKUL et al., 2009). Yield and bread-making quality is infl uenced by genotype, growth conditions and fertilization regime (JOHANSSON et al., 2004). Responses of wheat to nitrogen application alone have been well recognized for many varieties under different climates (EREKUL et al., 2009; TEA et al., 2007; GUARDA et al., 2004; JOHANSON et al., 2004). Besides nitrogen, the essential role of sulphur in plant growth and development is well known (ZHAO et al., 1999a; STEINFURTH et al., 2012). Deficiency of sulphur can decrease grain yield but has a stronger infl uence on bread-making quality (FULLINGTON et al., 1987; SHAHSAVANI and GHOLAMI, 2008), due to the essential role of disulphide bonds in maintaining gluten functionality (ZHAO et al, 1999b). Function of N and S are closely interrelated and an optimal N/S ratio improves bread-making quality. Interactions of nitrogen and sulphur fertilization have not been widely investigated (ZHAO et al., 1999c; TEA et al., 2007). Although wheat require only a modest amount of sulphur (about 15-30 kg/ha) for optimum growth and grain yield (ZHAO et al., 1999a; ZHAO et al., 1999b), defi ciency of sulphur has become increasingly widespread in Europe in recent years (SCHNUG, 1991; ZHAO et al., 1999c). Reports on the response of cereals to sulphur nutrition, especially in the Mediterranean climate, are not numerous. This research was conducted for two growing seasons, (2008-2009 and 2009-2010) fi rstly to determine to our knowledge in Aegean region about the effects of different doses of nitrogen combined with sulphur fertilizing under fi eld conditions with respect to yield and bread- making quality of two wheat varieties, widely grown in western parts of Turkey. Materials and methods Trials were performed in 2008-2009 and 2009-2010 at Adnan Menderes University Research and Experimental Farm located in western Turkey at 37º 44’ N 27º 44’ E and at 65 m above sea level. Mean annual precipitation and temperature (1970-2005) was 648.9 mm and 17.6 ºC, respectively. Average monthly temperatures were lower in 2008-2009 than in 2009-2010 with 14.8 ºC and 15.4 ºC, resp. The soil texture is classifi ed as a sandy loam and the soil type is a Calcaric Fluvisol (FAO-classifi cation). Soil samples were taken to determine the amount of extractable sulphate-S (Tab. 1), which was extracted with 0.016 M KH2PO4 and determined with ion chromatography (ZHAO and GRATH, 1994). Total N was determined by Kjeldahl method (BREMNER and MULVANEY, 1982), available P by the method of OLSEN et al. (1954) and available K was analyzed in 1M NH4OAc extract by fl ame emission. The experimental design was a split-split plot with randomized complete block and four replications. Wheat (Triticum aestivum L.) varieties Golia and Sagittario were sown between mid-November and the beginning of December (04.12.2008; 26.11.2009) with a rate of 500 seeds m-2. For the phenological growth stages, the BBCH-scale was used (BBCH MONOGRAPH, 2001). N treatments (Ammonium nitrate) were 0 kg ha-1 N, 70 kg ha-1 N (at sowing), 140 kg ha-1 N (70 kg sowing, + 35 kg beginning of tillering, + 35 kg beginning of shooting) and 210 kg ha-1 N (70 kg sowing, + 70 kg, beginning of tillering, + 70 kg beginning of shooting). Sulphur treatment 0 and 40 kg ha-1 S were applied as gypsum be- Tab. 1: Chemical properties of soil (Ap-horizon) at the study site in Aydin Soil Texture (%) Horizon Sand Silt Clay N P K Ca Mg S1 OM2 pH (%) (ppm) (ppm) (ppm) (ppm) (mg/kg) Ap 65.2 23.2 11.6 0.13 18.0 383 2897 379 6.3 1.50 8.0 1 Available sulphur 2 Organic matter 18 O. Erekul, K.-P. Götz, Y.O. Koca tween the end of February and the beginning of March (beginning to end of tillering). Further fi eld management (P and K fertilization, weed control and pest management) were carried out in accordance to the nutrient state of the soil and crop development. The sampling area for grain yield was 4.8 m2 in the centre of the plot (plot size: 12.0 m2, grain test weight was measured on a 250 g sample and expressed as kg hl-1). Grains were milled by the AMG (Ardic Medical Gida, Ankara, Turkey) laboratory mill. Grain N-content was determined by Kjeldahl method. Starch content was determined on a dry weight basis by near infrared refl ectance spectroscopy (NIRS), using a Perten DA-7200 instrument (Perten Co., Huddinge, Sweden). Bread-making quality analyses were evaluated by the Standard Method of the International Association of Cereal Chemistry (ICC, 1986): wet gluten and gluten index by ICC 137, 155 and 158, using a Glutomatic 2200 instrument; sedimentation values by Zeleny Sedimentation Test (ICC 116); the falling number according to ICC 107. The data were analysed by using statistical software SPSS, version 14.0, univariate model and Least Signifi cant Difference (LSD) among means of cultivars and N and S doses in each year were tested at the P<0.05 level of probability. Results and discussion Nitrogen and year as main effect showed a signifi cant infl uence on yield (univariate model; data not shown). However, the main effect yield was not different between the cultivars and independend from the sulphur application. The grain yield ranged in 2009 from 2590 kg ha-1 for the control to 4081 kg ha-1 for the highest N- application for Golia and for Sagittario from 2909 kg ha-1 to 4172 kg ha-1 (Tab. 2). The applied sulphur resulted in higher yield up to 4322 and 4379 ha-1 for Golia and Sagittario, resp., but the increase was not signifi cant. The grain yield was higher in 2010 and ranged from 3015 kg ha-1 for the control to 4698 kg ha-1 for Golia and for Sagittario from 2963 kg ha-1 to 4627 kg ha-1. No remarkable benefi ts were noticed at a higher yield level in 2010. In Aegean Region, grain yield average under rain fed conditions is 1,5 times higher than the average of Turkey. The difference in effectiveness of nitrogen and sulphur fertilization in the two years was fi rstly and primarily caused by different weather conditions during the growth periods. In this study the varieties remained below their yield potential of about 8000 to 9000 kg ha-1 (DINC and EREKUL, 2010). Intensive rains in 2009 particularly in January and February (total 428.2 mm) caused reducing effects during tillering period (BBCH 20- BBCH 29) and later on ear density (ears m-2; data not shown). Also the amount and distribution of rain in Aegean Region in May can affect the yield formation remarkably. This was more advantageous in May 2010, rain which were higher than 2009, led to remarkably higher yield than 2009. Positive effects of sulphur fertilizer on wheat yield have been noticed also in other studies (RASMUSSEN and KRESGE, 1986; ZHAO et al., 1999c). Although in this study, which is the fi rst study in our region in terms of the effects of nitrogen and sulphur fertilization and its combinations on quality parameters of wheat, gave progressive results, the acquired differences haven’t found to be statistically signifi cant. Similar results in terms of yield were mentioned in a study by PAULSEN (1999). When both years were compared, it can be concluded that Sagittario is more susceptible to sulphur fertilization than Golia. The measured parameter of the internal grain quality, like grain protein, fl our protein, gluten index, sedimentation value, falling number, with the exeption of the gluten content, were signifi cantly infl uenced by the cultivar, nitrogen application and year. Considerably infl uenced by the sulphur application was the protein content in the fl our, the gluten index and the sedimentation value (univariate model; data not shown). As one of the bread making qualities, protein content in both wheat varieties increases in paralel with the increasing nitrogen application. These increases are signifi cant especially between the control (0 kg ha-1 N) and 70/140 kg ha-1 N and 210 kg ha-1 N (Tab. 3). Protein content ranged between 11.5% and 16.1% and between 12.3% and 15.3 %, in 2009 and 2010, resp., without any distinctive effect of sulphur fertilization. In Aegean Region decreasing rainfall in the second half of May and increasing temperatures triggers shortening of grain fi lling period (BBCH 61-BBCH 87), decreasing carbohydrate accumulation, thus increasing the protein content (GOODING et al., 2003; EREKUL et al., 2011). When compared to results of other studies in Mediterranean climates (GUARDA et al., 2004), the protein contents determined in our investigation were either similar or higher. The protein content in fl our is the main quality criterion for wheat, especially for bread making (TRIBOI et al., 2006) and is generally lower than the amount in the grain (ZHAO et al., 1999b). The protein content in the fl our was about 0.4% to 1.3% lower than the protein content in the whole grain and ranged between 10.8% and 15.3% in 2009 and 2010. Effects of increasing nitrogen doses on protein content in fl our have been similar to the effect on protein content in grain. The application of sulphur did not affect the protein content; therefore our results are in accordance with STEINFURTH et al., 2012 and ZHAO et al., (1999b), but not with SHAHSAVANI and GHOLAMI (2008). The effect of sulphure fertilizer on fl our protein content in comparison with the grain protein content was principally the same in Sagittario however the differences are not signifi cant. Different nitrogen doses led to the known effect on protein content (BORGHI et al., 1997). Sulphur fertilization can have a comparatively low and unstable effect on wheat fl our protein content (JÄRVAN et al., 2008). When the protein content in fl our has been examined it can be seen that sulphure application in both wheat varietes is more distinctive Tab. 2: Effect of nitrogen and sulphur fertilization on grain yield of two wheat varieties. Year/ Year/ Year/ 2009 2010 Variety Golia Sagittario Golia Sagittario Grain yield (kg ha-1) N / S Doses 0 40 0 40 0 40 0 40 (kg ha-1) 0 2590 2923 2909 2978 3015 3016 2963 3383 70 3481 3634 3397 3534 4218 4006 3890 4026 140 3854 4242 3846 3955 4540 4280 4240 4196 210 4081 4322 4172 4379 4698 4615 4627 4813 LSD (0.05) = 432 LSD (0.05) = 464 LSD (0.05) = 432 LSD (0.05) = 464 Sulphur and nitrogen fertilization of wheat (Triticum aestivum L.) performance under Mediterranean climate 19 than on grain protein content and the differences in some cases have been recorded signifi cant (TEA et al., 2007). The grain quality is a complex of physical and chemical characteristics and its expression depends on their genetic potential and is infl uenced by environmental conditions (JOHANSSON, 2002; JOHANSSON et al., 2004). In our study, there is found to be no dilution effect between protein content and grain yield (ACUNA et al., 2005; EREKUL et al., 2009). In 2009 and 2010 starch content ranged between 60.1-64.8% (data not shown), which is in the range of values for wheat given by GOODING and DAVIES (1997) and JOHANSSON (2002). It is known that in developed kernels proteins occur fi rst and thereafter starch is produced (SOWERS et al., 1994). Therefore, high crude protein contents were accompanied by lowering starch content in both cereal varieties. Protein and starch contents were found to be inversely correlated, which is in line with GOODING and DAVIES (1997) and VISWANATHAN and KHANNA-CHOPRA (2001). Wet gluten content ranged between 27% and 33.9 % in 2009 (Tab. 4). Increasing nitrogen have caused signifi cant increases in wet gluten contents which was also found by PECHANEK et al. (1997). Application of sulphure in 2009 has caused increase in wet gluten content in the doses of 70 kg ha-1 N, 140 kg ha-1 N and 210 kg ha-1 N in Golia and in the doses of 140 kg ha-1 N and 210 kg ha-1 N in Sagittario. However these increases have not been signifi cant in general. Wet gluten content in Sagittario was higher than in Golia in 2009. These differences are signifi cant in the control (0 kg ha-1 N) with and without sulphur. Increase in nitrogen fertilization in 2010 led to higher wet gluten content but not as pronounced as the amount in 2009. S-fertilization resulted in the variety Golia in all N levels in higher gluten content, however the differences were not signifi cant. In Sagittario variety ultimately the opposite was observed at all nitrogen levels. The decreases occured here have not become in signifi cant levels. In the second year as well, Sagittario general produced more wet gluten than Golia however in any case, the difference was not signifi cant. Tab. 3: Effect of nitrogen and sulphur fertilization on protein content in grain and fl our of two wheat varieties Year / Year / Year / 2009 2010 Variety Golia Sagittario Golia Sagittario Grain protein content (%) N / S Doses 0 40 0 40 0 40 0 40 (kg ha-1) 0 12.0 11.5 13.1 12.4 12.3 12.7 13.0 12.5 70 14.0 14.3 14.4 14.0 13.8 13.5 13.8 14.2 140 15.2 14.9 15.1 15.7 14.2 14.4 14.0 14.8 210 15.8 15.9 15.9 16.1 14.9 15.1 15.1 15.3 LSD (0.05) = 0.9 LSD (0.05) = 0.9 LSD (0.05) = 0.6 Protein content fl our (%) 0 40 0 40 0 40 0 40 0 11.1 10.8 12.2 11.8 11.8 11.9 12.6 11.9 70 13.2 13.3 13.1 13.6 13.0 12.8 13.2 13.7 140 14.2 14.1 14.5 14.8 13.2 13.9 13.2 14.0 210 14.5 15.0 15.0 15.3 13.7 14.3 14.3 14.6 LSD (0.05) = 0.8 LSD (0.05) = 0.8 LSD (0.05) = 0.4 Tab. 4: Effect of nitrogen and sulphur fertilization on wet gluten content and gluten index of two wheat varieties Year / Year / Year / 2009 2010 Variety Golia Sagittario Golia Sagittario Wet gluten content (%) N / S Doses 0 40 0 40 0 40 0 40 (kg ha-1) 0 27.4 27.0 30.7 28.9 28.9 29.0 29.3 29.1 70 30.1 31.8 31.9 30.4 30.2 31.2 31.6 30.9 140 31.6 32.4 32.1 32.8 30.6 31.8 32.4 31.7 210 32.8 33.1 33.5 33.9 31.9 32.5 33.3 33.1 LSD (0.05) = 1.2 LSD (0.05) = 2.0 Gluten index (%) 0 40 0 40 0 40 0 40 0 85 86 76 79 86 86 79 80 70 88 88 80 81 88 90 80 85 140 90 90 82 81 91 92 83 83 210 89 90 80 81 90 91 81 82 LSD (0.05) = 1.8 LSD (0.05) = 1.9 Year / Year / LSD (0.05) = 1.2 LSD (0.05) = 2.0 20 O. Erekul, K.-P. Götz, Y.O. Koca Generally, we found wet-gluten to be mostly over 28%, which we assume to be between high and very high values (EREKUL and KÖHN, 2006). The effect of sulphur fertilizing on wet gluten content has not been so distinctive when both years have been considered but much rather the increases of wet gluten content have been found in Golia after sulphur fertilizing. WIESER et al. (2004) concluded that the effect of the sulphur fertilizer on gluten proteins in pot experiments were not remarkable. However the results of JÄRVAN et al. (2008) are in accordance with our study. Gluten index which indicates the quality of the gluten has ranged between 76% and 90% in 2009. The increasing doses of nitrogen in both wheat varieties have caused the gluten index parameters to increase up to 140 kg ha-1 N (Tab. 4). These increases are almost signifi cant at all N-levels. Application of 210 kg ha-1 N had no infl uence on the gluten index. Application of sulphur fertilizer have resulted positively in both wheat varieties, but except for one N application obtained for Sagittario, all differences have not been found signifi cant. Similar results about the effi ciency of sulphur fertilizer application have been observed also in 2010. The gluten index reached the highest values when 70 kg ha-1 N and 140 kg ha-1 N was applied in 2010. Golia achieved signifi cantly higher gluten index values than Sagittario in terms of all nitrogen and sulphur doses and in both years. The gluten index has been recently introduced as a better measure of wheat processing quality, rather than wet gluten content (DENG et al., 2005). However the gluten index is a new, and yet seldom used parameter for wheat bread-making quality; little information is available on the relationship between the gluten index and other indices, or about the infl uence of environment on the gluten index (JOHANSSON et al., 2002). CURIC et al. (2001) reported optimum values between 75% and 90% for gluten-index of wheat. In our study in both years, the gluten index values have been above 76%. These results are in accordance with JOHANSSON et al. (2004). In the same fertilizing doses in both trial years the gluten index values of Golia have signifi cantly higher values than Sagittario. This implies that the gluten quality and its dough characteristics of Golia is higher (KAHRIMAN, 2007). It is stated that in many studies done with sulphur fertilizer application, the gluten index among the quality parameters is affected positively at most (SCHÄFER and HONERMEIER, 2007; JÄRVAN et al., 2008). The increasing nitrogen doses have brought signifi cant increases of sedimentation values in both wheat varieties and sulphure doses. In general there has been more impact of the application of sulphure fertilizer on sedimentation values in both wheat varieties and years (Tab. 5). The application of sulphure fertilizer has resulted in equal or higher sedimentation values in all nitrogen applications in both varieties and years. Compared to the gluten index, Sagittario has produced signifi cantly higher sedimentation value in all nitrogen doses than Golia. Impacts of the applications of nitrogen and sulphur on sedimentation values of both wheat varieties have been similar in the second year of the trial. Furthermore in the second year of the trial as well, the Sagittario variety has produced signifi cantly higher sedimentation values in all nitrogen and sulphur levels than the Golia variety. The sedimentation value of the wheat varieties, characterizing the swelling capacity of gluten, exceeded the nominal value (20 ml) for bread-making wheat in both years. In all applications in both years, the minimum limit of 20 ml has been eminently exceeded. The positive effect of the sulphur fertilizer has been seen more on sedimentation value rather than on gluten index parameter. SCHÄFER and HONERMEIER (2007) reported that sulphur application created positive effects on sedimentation value but the results obtained were also not signifi cant. WEBER at al. (2008) put forward that the effect of additional sulphur application on sedimentation value is extremely limited. The sedimentation value of the Sagittario has higher values in both years than the Golia and based mainly on genotypic characteristics. Increasing nitrogen doses caused the protein contents to increase and due to this, the sedimentation values increase signifi cantly in both varieties and in both years. Similar results have also been reported in previous studies (GOODING et al., 2003). The falling number has been measured in order to determine impacts of nitrogen and sulphur fertilizer on alpha amylase activity in wheat fl our. The falling number values ranged between 333 s and 396 s in 2009 (Tab. 5). In 2009, any distinct impact of nitrogen and sulphur fertilizer has not been determined on the falling number. Sagittario showed substantially lower falling number values than the Golia variety. In 2010 the falling number values have ranged from 298 s to 351 s and showed lower values than 2009 without impact of nitrogen and sulphur fertilizer. The falling numbers, which allow for conclusions to the enzymatic state of the grain, to the expected baking volume, and to the grade of outgrowth, have an optimum range of 220 to 250 s for winter wheat (DIEPENBROCK et al., 2005). Falling number values in both varieties and years have been above Tab. 5: Effect of nitrogen and sulphur fertilization on sedimentation value and falling number of two wheat varieties Year/ Year/ Year/ 2009 2010 Variety Golia Sagittario Golia Sagittario Sedimentation value (ml) N / S Doses 0 40 0 40 0 40 0 40 (kg ha-1) 0 26 28 29 33 27 28 30 32 70 30 30 35 35 30 31 33 35 140 31 33 38 38 32 33 36 36 210 36 37 40 42 34 36 37 39 LSD (0.05) = 1.6 LSD (0.05) = 2.0 Falling number (s) 0 40 0 40 0 40 0 40 0 373 352 347 333 324 298 312 323 70 389 348 361 371 347 340 304 329 140 358 381 343 340 329 351 324 311 210 370 396 353 387 341 338 339 333 LSD (0.05) = 17 LSD (0.05) = 24 LSD (0.05) = 1.6 LSD (0.05) = 2.0 Sulphur and nitrogen fertilization of wheat (Triticum aestivum L.) performance under Mediterranean climate 21 the optimum values. Falling number values are affected by the climate conditions during the grain fi lling period (BBCH 61-BBCH 87) and primarily by rainfall more than the fertilizing (GOODING et al., 2003). When evaluated from that perspective, decrease in rainfalls and increase in temperatures in grain fi lling period in our region caused the falling number values to increase. This situation has caused enyzme activity of the fl our obtained to decrease. Similar results have also been reported by JOHANSSON (2002) and GOODING et al. (2003). It may also be possible to see differences among genotypes (EREKUL et al., 2009). In our study, Sagittario generally has lower falling number values than Golia. No signifi cant effect of nitrogen and sulphur fertilizing applications on falling number values have been found and these fi ndings are in accordance with the results of WEBER et al. (2008). Conclusion Quality characters of bread wheat have not adequately been examined on varieties grown in Western Turkey. Due to lack of information, wheat varieties have not been classifi ed into quality groups which cause inability to compare them with international wheat varieties. Under more favorable climatic conditions the grain yield could increased up to 210 kg ha-1 N without substantially losses in the grain quality. The results indicate that S-fertilization showed benefi cal effects in grain yield and in some bread-making quality parameters. S-fertilization on protein content was more remarkable in fl our than in grain. The most benefi ted quality parameter by sulphur was the gluten-index and especially the sedimentation value. In this respect, S-fertilization in improving bread making quality of the region should not be disregarded. However, an S fertilization of > 40 kg ha-1 would be advisable to prove more clearly effects on yield and quality parameters. Acknowledgements The authors are grateful to Dr. R. Krause for her help on the quality part at the Humboldt University of Berlin. 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ZHAO, F.J., SALMON, S.E., WITHERS, P.J., EVANS, E.J., MONAGHAN, J.M., SHEWRY, P.R., MCGRATH, S.P., 1999a: Responses of bread-making quality to sulphur in three wheat varieties. J. Sci. Food Agric. 79, 1865- 1874. ZHAO, F.J., SALMON, S.E., WITHERS, P.J., MONAGHAN, J.M., EVANS, E.J., SHEWRY, P.R., MCGRATH, S.P., 1999b: Variation in the breadmaking quality and rheological properties of wheat in relation to sulphur nutrition under fi eld conditions. Journal of Cereal Science, 30, 19-31. ZHAO, F.J., HAWKESFORD, M.J., MCGRATH, S.P., 1999c: Sulphur assimilation and effects on yield and quality of wheat. J. Cereal Sci. 30, 1-17. Address of the authors: Assoc. Prof. Dr. O. Erekul1 (corresponding author; e-mail: oerekul@adu. edu.tr) and Dr. Y.O. Koca1, Department of Crop Science, Faculty of Agri- culture, Adnan Menderes University, 09100 Aydin, Turkey; Dr. K.P. Götz2, Department of Crop and Animal Science, Faculty of Agriculture and Hor- ticulture, Humboldt-Universität zu Berlin, Albrecht-Thaer-Weg 5, D-14195 Berlin, Germany.