Field Crops Research 121 (2011) 240–247 Contents lists available at ScienceDirect Field Crops Research journal homepage: www.elsevier.com/locate/fcr Do barley and wheat (bread and durum) differ in grain weight stability through seasons and water–nitrogen treatments in a Mediterranean location? C. Mariano Cossani a,∗ , Gustavo A. Slafer a,b , Roxana Savin a a Department of Crop and Forest Sciences, University of Lleida, Centre UdL-IRTA, Av. Rovira Roure 191, 25198, Lleida, Spain b ICREA (Catalonian Institution for Research and Advanced Studies 1 ), Spain article info Article history: Received 16 September 2010 Received in revised form 11 December 2010 Accepted 12 December 2010 Keywords: Triticum aestivum Triticum durum Hordeum vulgare Grain growth Grain filling duration Grain nitrogen content Canopy temperature abstract Under Mediterranean environments, farmers usually prefer to sow barley rather than wheat as it is generally believed that barley yields more under stressful conditions. As terminal stresses such as high temperature and water are common constraints in Mediterranean regions, higher grain weight stability may confer a clear advantage in order to maintain higher yields. The objective of the present study was to compare the stability in terms of grain weight and its components for barley, bread wheat, and durum wheat, exploring a wide range of nitrogen and water availabilities in experiments conducted in a Mediterranean region. Grain weight ranged from 23.8 to 47.7 mg grain -1 , being higher for durum wheat than barley and bread wheat. Durum wheat presented higher variability both in maximum grain filling rate and duration of grain filling period than bread wheat or barley. The three species responded similarly in terms of grain nitrogen content to changes in the environmental conditions explored. It is concluded that in terms of grain weight barley is as stable as bread wheat. However, durum wheat presented a lower stability than barley and bread wheat. © 2011 Elsevier B.V. All rights reserved. 1. Introduction The large variability in grain yields that frequently occurs under Mediterranean environments often determines conservative strategies by farmers (Sadras et al., 2003). Many of the strategies used by farmers to avoid risks are related to efficient input man- agements in order to reduce crop costs, to the choice of cultivars with higher grain yield stability or to the application of site specific management practices. In rainfed agricultural systems of Catalo- nia (NE Spain), as well as in many other Mediterranean regions, farmers usually grow barley continuously in drought-prone areas generating monoculture regions. This is based on the assumption that yield of barley is more stable than that of other cereals (but see arguments in Cossani et al., 2007) and consequently it is expected in these dryland conditions that barley would yield consistently more than wheat (Anderson and Impiglia, 2002; Ryan et al., 2008). Although grain number dominates grain weight in cereal yield determination (e.g. Peltonen-Sainio et al., 2007), grain weight still Abbreviations: Cv, cultivar; CV, coefficient of variation; CTD, canopy temperature depression; AGW, average grain weight; Ta, time from anthesis; MGFR, maximum grain filling rate; DGF, duration of grain filling. ∗ Corresponding author. Tel.: +34 973 70 2599; fax: +34 973 23 8264. E-mail address: mariano.cossani@pvcf.udl.cat (C.M. Cossani). 1 www.icrea.es. varies and, in conditions prone to terminal stresses, yield sta- bility would be expectedly related to more stable grain weights (Khanna-Chopra and Viswanathan, 1999; Royo et al., 2006). Even though the better performance of barley over wheat under stressed Mediterranean conditions has not been consistently found in some comparative studies (Simpson and Siddique, 1994; Palumbo and Boggini, 1994; Cossani et al., 2009), it has been indeed confirmed in others (e.g. López-Casta ˜ neda and Richards, 1994; Josephides, 1993). Based on these evidences it can be hypothesized that barley grain weight would be more stable than grain weight of other cereals under Mediterranean environments. The effect of high temperatures and/or water stress during grain filling period in small cereals has been well documented (e.g. Stone and Nicolas, 1994 in bread wheat; Savin and Nicolas, 1996 and Voltas et al., 1999 in barley, and Rharrabti et al., 2003 in durum wheat). Grain weight stability, as well as grain filling parameters (duration and rate of grain filling) of different cereals, has not been widely compared, particularly under Mediterranean condi- tions. Fischer and Wood (1979), in a study conducted in Mexico, found that grain weight sensitivity to drought was only 4% higher in bread and durum wheat than in barley. Simpson and Siddique (1994) showed a similar response of wheat and barley in grain weight to changes in soil type (fine textured vs. coarse textured soil) in Western Australia. The main objective of the present work was to compare grain weight stability and its components in bread wheat, barley and 0378-4290/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.fcr.2010.12.013