SUMMARY

Over the period 1994-1997 investigations were conducted in oreder to study the effect of hybridson yield and yield components of corn. The investigations included 31 (1994) to 46 (1996) hybrids classified according to the length of the vegetation period into four FAO maturation groups (400, 500, 600 and 700). The highest average grain yield (14% moisture) was registered with the hybrids ot the maturation group 600 (8.60 t/ha). This proved to be higher by 0.35% only compared with the hybrid group 500: followed by 0.85% from the hybrid group 400 and cventually by 3.99% compared with the maturation group 700/1000-grain weight was highest in the hybrids of the maturation group 400 (344.01 g) and decreased evenly up to the maturation group 600 amounting to 316.77 g. The average moisture contentduring harvesting amounted to 23.63% in the hybrids of carliest maturation group and ranged up to 29.37% in the late maturing hybrids.

          Key words: corn, hybrids, grain yield, 1000-grain weight, moisture content.