PHOTOSYNTHETIC EFFICIENCY IN JUVENILE STAGE AND WINTER BARLEY BREEDING FOR IMPROVED GRAIN YIELD AND STABILITY

Photosynthetic efficiency parameters (Fv/Fm, ET0/ABS and PIABS) were investigated at the end of tillering stage of winter barley grown in stress environment (21.3% vol. water content of soil) and control (water content 30.4% vol.) in relation to grain yield per vegetative pot. The trial was conducted in vegetative pots according to the RBD method of two-factorial experiment with 10 winter barley cultivars (7 tworowed and 3 six-rowed) and 2 treatments in 3 repetitions. The stressed variant was exposed to water reduction three times (end of tillering stage, flag leaf to beginning of heading stage, grain filling stage). From sowing to maturity, the air temperature varied from -3.9°C to 32.9°C and water content from 16.4 % to 39.0 % of soil volume in vegetative pot. Significant differences were found for grain yield among the cultivars. The short-term drought stress caused significant reductions in grain yield per pot. The photosynthetic efficiency parameters were significant between cultivars, but significant effects for treatments and interaction were only detected for the Fv/Fm parameter. Photosynthetic efficiency parameters did not have significant correlation coefficients with grain yield and its stability in both treatments. Stability indexes of the parameters PIABS and Fv/Fm had positive but not significant correlations with grain yield in stressed variant (0.465 and 0.452) and stability index of grain yield (0.337 and 0.481).