QUALITY RESEARCH OF SEED MAIZE DURING DRY ING AND CONDITIONING .2. DRYING OF SEEDCORN AND STRESS CRACKS

During the experiments it was determined that after drying the hybrid Dea (dent corn character) showed a significantly lower number of stres s cracks than hybrid Helga (dent corn character). This fact was demons trated with the laboratory tests too. The increased number of stress c racks caused a lower germinative faculty and reduced germinating power (mean quality). The most important parameters for the stress crack fo rmation found by the laboratory tests were the initial drying temperat ure and the drying rate during the first ten hours. The hybrid Helga s howed an increase in stress cracks formation at the temperature of 36 degrees C, the hybrid Dea only at 40 degrees C. The large-round kernel s showed the highest number of stress cracks in both hybrids. The high er number of stress cracks cause the decrease of strength of the kerne ls. The seeds with stress cracks break by lower compressive force (non e stress cracks - from 200 N to 730 N, multiple stress cracks - from 1 02 N to 284 N), their deformation curves are flater and they do not ex hibit a clear bio-yield point. High number of stress cracks increase t he quantity of damaged corn caused by dynamic drag (shelling, transit, etc.).