EFFECTS OF HYBRID AND DAMAGE ON MOLD DEVELOPMENT DURING LOW TEMPERATURE DRYING AND STORAGE OF HIGH MOISTURE SHELLED CORN

Several corn hybrids either resistant or susceptible to storage mold were harvested with a combine and stored at high moistures (19 to 24% moisture, wet basis) in 0.81 m³ (23 bu) bins nd in “mini-bins” containing 1200 g (2.6 lbs). For several hybrids, two damage levels were achieved by adjusting combine cylinder speed. Storage conditions were the same as those found in a low temperature drying bin. Mold growth in the bins and “mini-bins” was monitored by determining number of propagules, percent seeds fine material was removed from all hybrids tested in 1986, whereas in 1985 it was not removed. This probably improved the storability of the 198 6 corn and reduced the differences in mold invasion. Furthermore, the sporulation and growth of mold were lower and differences may not have had time to develop.

Bin and small scale tests were consistent in differentiating the relative resistance of hybrids and they agreed with results of laboratory studies (Friday, 19,87). Some of the observed differences can be attributed to physical damage. However, there was an incremental decrease in storability above that which could be explained by damage, which the authors believe was caused by the hybrid effect. FRB73 × Mol7 was consistently more resistant to storage molds than the other hybrids tested. FRB73 × Mol7 and FR35 × FR20 displayed a higher level of mold resistance in all storage tests while P3707 and P3377 were consistently more susceptible. (Authors note: not all Pioneer hybrids are more susceptible to storage molds as some Pioneer hybrids have been found to store well in laboratory tests.)

The agreement of the bin, small scale, and laboratory studies suggests that hybrids can be screened for mold resistance in the laboratory. Hopefully, this will encourage plant breeders to begin such screening. This would be even more feasible if the laboratory procedures could be simplified and if the incubation time prior to evaluation for mold invasion could be reduced.