Management Effects on Kernel Breakage Susceptibility of Early Maturing Corn Hybrids

The tendency of corn (Zea mays L.) kernels to break during post-harvest handling causes problems for several user groups. Crop management factors have been reported to influence breakage susceptibility, but the effects of hybrid, plant density, harvest moisture content, and drying temperature on grain corn breakage susceptibility have not yet been investigated in a single study. To this end, a field experiment was established in May 1985, at the Arkell Research Station, Arkell, Ontario. Five commercial hybrids, Hyland HL2280, DeKalb XL11, Co-op 2645, First Line 1636, and Pioneer 3949, were grown at 5.6 and 7.1 plants w2, harvested at 310 and 240 g kg⁻¹ moisture content (wet basis) and dried at 30 and 80°C to approximately 150 g kg⁻¹ moisture content. A Wisconsin Breakage Tester was used to measure breakage susceptibility. In the breakage tests, the main effects were statistically significant, as well as the interactions of hybrid with plant density, harvest moisture, and drying temperature, and of harvest moisture with drying temperature. Of these, only the interaction of hybrid with drying temperature resulted in differences large enough to be commercially significant. Four hybrids were relatively resistant to breakage when dried at 30°C; when dried at 80 <C, increases in breakage susceptibility were much larger for two hybrids than for the other three. Of the other parameters measured, the degree of multiple stress cracking and kernel length were most strongly related to breakage susceptibility, but levels of severe kernel damage and fine broken corn (<4.76 mm), and kernel thickness were also related to breakage susceptibility. Test weight was not related to breakage susceptibility. Contribution from the Dep. ofCrop Sci., Univ. of Guelph. Part of the thesis submitted by the senior author in partial fulfillment of the M.Sc. degree.