Formation of crop struc­ture of corn hybrids at different seeding dates

Purpose. To determine the features of the formation of biometric indicators of the corn hybrids yield at diffe­rent sowing dates in the conditions of the Forest-Steppe of Ukraine. Methods. Field experiments were laid on a plot of the experimental field of the research and production bree­ding enterprise LLC “Rasava” (Pustovarivka village, Skvyrskyi district, Kyiv region), located in the Right-Bank Forest-Steppe of Ukraine. Economically valuable and morpho-biological parameters of corn hybrids were studied according to a unified method for determining the indices of suitability for distribution in Ukraine. Results. The morphometric indices of the plant productivity formation and the yield of corn hybrids (plant height, length of the ear, number of grain rows, number of grains per row, grain yield from the ear) at the different dates of sowing (April 25, 10 and 25) were the most stable at the early term (April 25). The early-ripe hybrid ‘Richka SV’ provided the highest yield at sowing on April 25 – 11.6 t/ha, which is 1.5 t/ha more than at the traditionally accepted date of sowing – the first decade of May (May 10). The medium early hybrid ‘Richka S’, also at an early sowing date (April 25), produced yields of 11.3 t/ha, which is 0.6 t/ha more than during sowing on May 10. Conclusions. The morphometric indices of the formation of plant productivity and the timing of seeding affect the yield of corn hybrids in the conditions of the Forest-Steppe of Ukraine.