Yield potential of spring malting barley (Hordeum vulgare L.) varieties in the growing conditions of south-western Slovakia

The field experiment was set up as a block plot design with four replications on the experimental base of the Central Controlling and Testing Institute in Agriculture situated in south-western Slovakia during 2011-2012. Spring malting barley varieties were growing after sugar beet and spring barley forecrops. Besides the year condition, the forecrop value significantly influenced the variability of grain yield. Interaction of forecrop with year condition contributed significantly to the overall variability of yield and was higher than that of the interaction of variety and year. Due to the balanced set of genotypes, variability of yield influenced by varieties was relatively low in both very contrasting years. Two year average yield was in relatively narrow range of 6.05 t*ha-1- 6.66 t*ha-1. Due to the very dry condition in 2012, mainly during crucial period of yield formation, average yield of evaluated genotypes decreases by 43% with comparison to 2011. The phenotypic plasticity of evaluated genotypes was reflected in less favourable weather condition of 2012 in range of 0.97 t*ha-1 grain or 1.14 t*ha-1 grain in good growing conditions of the year 2011, respectively. Better forecrop value of spring barley with comparison to sugar beet was confirmed in both evaluated year. Significantly higher yield (7.10 t*ha-1) of grain was achieved after spring barley forecrop with comparison to 5.38 t*ha-1 of grain after sugar beet forecrop. For better interpretation of forecrop value it is proposed Environmental index for “forecrop gain” or “forecrop lost”, calculated separately as share of increasing or decreasing grain yield due to the forecrop for at least two agronomically different years