384 AJCS 4(6):384-389 (2010) ISSN:1835-2707 Effect of organic and inorganic fertilizers on grain yield and protein banding pattern of wheat Tayebeh Abedi, Abass Alemzadeh* and Seyed Abdolreza Kazemeini Department of Crop Production and Plant Breeding, School of Agriculture, Shiraz University, Shiraz, Iran *Corresponding author: alemzadeh@shirazu.ac.ir Abstract In order to evaluate the effects of different levels of inorganic (0, 80, 160 and 240 kg Nitrogen ha -1 ) and organic (0, 30 and 60 Mg municipal waste compost ha -1 ) fertilizers on wheat grain yield, gluten content, protein variability and protein banding pattern on polyacrylamide gel in different growth stages of irrigated wheat, a field experiment was conducted at research station of the School of Agriculture, Shiraz University at Bajgah in 2007. Results indicated that the highest wheat grain yield was achieved when the plants were fertilized with 160 kg N ha -1 and 30 Mg compost ha -1 . Among yield components, spikes plant -1 , seeds spike -1 and 1000 kernels weight were significantly increased with increasing the level of nitrogen. However, there was no significant difference between 160 and 240 kg N ha -1 . There was no significant effect of N fertilization on seed protein and gluten content, however the highest amount of seed protein was obtained in 60 Mg compost ha -1 at all levels of nitrogen. The SDS-PAGE was performed to investigate differences between proteins banding pattern in different growth stages under different levels of N and compost. Protein banding pattern showed no polymorphism in tillering and stem elongation stages. However, in ear emergence in 160 kg N ha -1 and in the all compost levels, density of a 50 kDa band was increased specifically in 60 Mg compost ha -1 . Furthermore, seed water soluble proteins, Albumin and Globulin, showed no polymorphism. All in all, it is possible to obtain maximum grain yield, protein and gluten, just in 160 kg ha -1 nitrogen level. Thus, it shows the positive impact of compost application on reduction of chemical fertilizer use. Keyword: Compost, Gluten, Grain yield, Nitrogen fertilization, Protein, Wheat. Introduction Cereals are an important dietary protein source throughout the world, because they constitute the main protein and energy supply in most countries (Bos et al. 2005). Wheat is one of the major cereal crops with a unique protein, which is consumed by humans and is grown around the world in diverse environments. Wheat seed-storage proteins according to their solubility properties are traditionally classified into four classes; albumins, globulins, prolamins and glutelins. Gluten, the most abundant wheat endosperm protein, is a large complex mainly composed of polymeric and mono- meric proteins known as glutenins and gliadins, respectively (MacRitchie 1994). It has already been known that gluten proteins have a premier role in wheat flour quality. It is recognized that variation in protein content and composition significantly affect wheat quality with a subsequent influence on baking properties (Borghi et al. 1995; Daniel and Triboi 2000; Johansson and Svensson 1999; Johansson et al. 2001; Wooding et al. 2000). Wheat protein content and baking quality highly depend on genetic background and environm- ental factors, especially influence of drought and heat stress, during the grain filling period and nitrogen availability (soil N, rate and time of N application) (Altenbach et al. 2002; Dupont and Altenbach 2003; Luo et al. 2000; Ottman et al. 2000; Rharrabti et al. 2001; Tea et al. 2004). Nitrogen rate, type of nitrogen, and timing of its application are important factors to increase wheat yield (Garrido-Lestache et al. 2005; Grant et al. 2001; López -Bellido et al. 1998). Furthermore, N fertilization is useful to enhance the baking quality parameters such as protein content and protein quality (Grant et al. 2001). Some studies showed that N fertilization increases the total quantity of flour proteins, resulting in an increase in both gliadins and glutenins (Dupont and Altenbach 2003; Johansson et al. 2001; Johansson et al. 2004; Martre et al. 2003; Triboi et al. 2000). The use of chemical fertilizers has been increased worldwide for cereal production (Abril et al. 2007) due to availability of inexpensive fertili- zers (Graham and Vance 2000). The continued use of chemical fertilizers causes health and environmental hazards such as ground and surface water pollution by nitrate leaching (Pimentel 1996). So, reducing the amount of nitrogen fertilizers applied to the field without a nitrogen deficiency will be the main challenge in field management. One of the possible options to reduce the use of chemical fertilizer could be recycling of organic wastes. Compost as the organic waste can be a valuable and inexpensive fertilizer and source of plant nutrients. Positive effects of organic waste on soil structure, aggregate stability and water-holding capacity were reported in several studies (Jedidi et al. 2004; Odlare et al. 2008; Shen and Shen 2001; Wells et al. 2000). Furthermore, compost has a high nutritional value, with high concentrations of especially nitrogen, phosphorus and potassium, while the contamination by heavy metals and other toxic substances are very low (Asghar et al. 2006). Previous studies showed that the combination of compost with chemical fertilizer further enhanced the biomass and grain yield of crops (Sarwar et al. 2007; Sarwar et al. 2008;