RELATIVE STORABILITY OF HIGH–OIL AND BT CORN HYBRIDS COMPARED TO CONVENTIONAL HYBRIDS

Abstract

The objectives of this study were to compare relative storability for five pairs of normaloil content and highoilcontent corn (Zea mays) hybrids, and for five pairs of conventional and Bt corn hybrids, stored at 20.C (68.F) and at twodifferent moisture values (19% and 22%, wet basis). Paired hybrids had similar parent genetics. Carbon dioxide productionby corn samples was used to calculate dry matter loss (DML), and time to 0.5% DML was used as the primary indicator ofstorability. Change in the fat acidity content of normaloil and highoil corn hybrids was determined and used as anotherpossible indicator of relative storability.<br><br>The mean adjusted times to 0.5% DML for normaloil and highoil corn hybrids were significantly different at a 0.05probability level for all five hybrid pairs at 19% moisture, but time to 0.5% DML was significantly different for only two hybridpairs at 22% moisture. The deterioration rate for highoil corn was faster than for normaloil corn in most hybrid pairs atboth 19% and 22% moisture. Fat acidity values were significantly different at a 0.05 probability level for all hybrid pairs atboth moisture levels, both before and after storability tests. Fat acidity values for highoil corn hybrids were much higherthan for comparable normaloil content corn hybrids after the test. There was a strong positive correlation between oil contentand fat acidity after storability tests at both moistures. In general, the highoil corn hybrids had higher levels of damagedkernels (DKT) at the end of the storability tests, at both 19% and 22% moisture. Fat acidity and DKT results indicate that,at a given moisture content, some highoil corn hybrids might not store as well as normaloil content corn.<br><br>For conventional and Bt corn hybrids, the mean adjusted times to 0.5% DML were significantly different at a 0.05probability level for three hybrid pairs at 19% moisture and for four hybrid pairs at 22% moisture. In some cases, time to 0.5%DML was greater for the conventional hybrid, and in other cases, time to 0.5% DML was greater for the Bt hybrid. Differencesin fungal counts and DKT values after storability tests were small for comparable hybrid pairs of conventional and Bt cornat both moisture levels. These results do not allow any conclusions to be drawn about the relative storability of Bt corn hybridscompared to conventional hybrids.