Analysis of Yield Components of F1 Hybrids of Crosses between Spring and Winter Wheat Types (Triticum aestivum L.)

Sa？etak F1 hybrids were produced using the German spring wheat variety Remus as a female parent and eight Croatian wheat varieties (six winter and two spring types) as male parents. The heterosis (MP-mid parent, BP-better parent) for five yield components was investigated in eight cross combinations. Data are based on field trial. All the combinations tested gave average heterosis (MP, BP) for 1000-grain weight (14.38%, 6.12%) and grain weight per spike (11.47%, 3.68%). The highest heterosis (MP, BP) was found for 1000-grain weight (35.27%, 28.42%) in the hybrid Remus/Sivka and for grain weight per spike (20. 45%, 19.1%) in the hybrid Remus/Dukat. These data showed that the spring wheat variety Remus could be used in cross combinations for improvement of yield through higher 1000-grain weight and grain weight per spike