original research paper Acta Agriculturae Serbica, Vol. XV, 30 (2010) 117-123 Impact of Precipitation and Temperature on Wheat (Triticum Aestivum L.) Yields in Eastern Croatia Marija Marijanovi, Antonela Markulj, Monika Tkalec, Anita Jozi, Vlado Kovaevi University J. J. Strossmayer in Osijek, Faculty of Agriculture, Osijek, Croatia Abstract: Wheat after maize is the most commonly cultivated field crop in Croatia. In 2005-2007, it was cultivated on 165,721 ha/year or on about 20% of arable land. The majority of wheat acreage (about 76 %) is located in eastern Croatia. Considerable yield variations among years are mainly caused by weather characteristics, especially precipitation and temperature regimes. For example, during three favorable growing seasons (MFS: years of harvest 1984, 1988 and 1989), the mean yield of wheat in eastern Croatia was 5.53 t/ha, while during the three less favorable years (LFS: 1978, 1980 and 1982) it was 4.22 t/ha or 24% lower. Precipitation values (the data of Osijek Weather Bureau) during the growing season (a = October –June; b = November + December) were higher in LFS (a =522 and 463 mm, b = 146 mm and 79 mm, for LFS and MFS, respectively). During 1996-2007, differences in wheat yield in the region ranged from 3.62 to 5.00 t/ha. Precipitations during the growing season (a = October- June; b = November + December of the previous year: 3-year means in Osijek) were higher in the LFS, especially during November + December period (a =522 and 463 mm, b = 146 mm and 79 mm, for the LFS and MFS, respectively). Wheat yields in Vukovar- Syrmium and Osijek-Barannya Counties were 12 % (mean 4.61 t/ha) higher than in Virovitica-Podravina and Brod-Posavina Counties (mean 4.12 t/ha). Irrespective of the complex relationship between wheat yields and weather characteristics (precipitation and mean air-temperatures), there are indications that moderate well-distributed precipitation coupled with mild winter are more favorable for wheat growing than excess precipitation, especially in autumn, and colder winters. Key words: precipitation, temperature, wheat yield, Croatia. This paper was presented and approved for publication at the 6 th Conference of Agronomy Students held in aak, 27-29 August 2009