Figure 1

Frost episodes in Foradada (Spain, winter 2004/05) and Fiorenzuola (Italy, winter 2007/08). a. Daily maximum and minimum temperature from sowing to the end of March when cold tolerance was scored. The average mean minimum temperatures were −2.7°C and −1.1°C for Foradada (i) and Fiorenzuola (ii) trials respectively, while the absolute lowest temperatures were −12.7°C and −8.6°C for Foradada and Fiorenzuola trials respectively. An alternation of freezing and thaw periods was observed. b. Differential frost damage in winter barley plots (Foradada, Spain spring 2005). Cold injury was visually estimated on a 0–5 scale: 0. all plants killed; 1. whole plants yellowed and 50% of plant mortality; 2. whole plants yellowed and 20% of plant mortality; 3. fully yellowed basal leaves; 4. half yellowed basal leaves; 5. no damage.