Die Bodenkultur - Journal for Land Management, Food and Environment
V. NAPLAVA, H. WEINGARTMANN and J. BOXBERGER:
Quality research of seed maize during drying and conditioning
Part 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 stress cracks than hybrid Helga (dent corn character). This fact was demonstrated with the laboratory tests too. The increased number of stress cracks caused a lower germinative faculty and reduced germinating power (mean quality). The most important parameters for the stress crack formation found by the laboratory tests were the initial drying temperature and the drying rate during the first ten hours. The hybrid Helga showed an increase in stress cracks formation at the temperature of 36 "C, the hybrid Dea only at 40 'C. The large-round kernels showed the highest number of stress cracks in both hybrids.
The higher number of stress cracks cause the decrease of strength of the kernels.
The seeds with stress cracks break by lower compressive force (none stress cracks - from 200 N to 730 N, multiple stress cracks - from 102 N to 284 N), their deformation curves are flater and they do not exhibit a clear bio-yield point. High number of stress cracks increase the quantity of damaged corn caused by dynamic drag (shelling, transit, etc.).
Key-words: maize, drying of seedcorn, stress cracks, breaking point.