Photosynthetic Efficiency in Juvenile Stage and Winter Barley Breeding for Improved Grain Yield and Stability

Different winter barley cultivars showed various levels of genetic tolerance when they were exposed to different stress conditions. Therefore, investigations of interaction among genotypes (cultivars) and environments give useful information concerning yield stability and quality in barley (Blum, 1989; Ceccarelli et al., 1998, 2000; Lalić et al., 2007, 2009). Drought conditions frequently give characteristic of environments that cause stress effect on plant with unfavorable influence to physiological and morphological characters and to grain yield of agricultural plants. Bray et al. (2006) reported that the abiotic stress can decrease the grain yield of barley up to 75.4 % of record yield in the world. In the period from 1982 to 2009 (data of State Bureau for Statistics, Zagreb), the average grain yield of barley in the Republic of Croatia varied from 2.5 t/ha (2003) to 4.3 t/ha (2008). The lowest grain yield of barley was obtained in 2003, the extremely dry year. This is why