MON863 X MON810 X NK603 (OECD identifier: MON-ØØ863-5 x MON-ØØ81Ø-6 x MON-ØØ6Ø3-6) maize is an F1 hybrid resulting from the hybridization of the insect-resistant stacked maize inbred line MON863 X MON810 (MON-ØØ863-5 x MON-ØØ81Ø-6), and the herbicide tolerant inbred line NK603 (MON-ØØ6Ø3-6).  This F1 stacked hybrid is resistant to coleopterans, such as the Corn Rootworm, lepidopterans, such as the European Corn Borer, and is tolerant to the herbicide glyphosate.   MON863 X MON810 X NK603 is a product of traditional plant breeding, and therefore is not automatically subject to regulation in all jurisdictions as are transgenic plants resulting from recombinant DNA technologies. Certain jurisdictions may request notification in advance of the release of a stacked hybrid, or may request information to conduct an environmental and food safety assessment.  Examples of jurisdictions that require either notification or information about stacked hybrids prior to their release into the environment, and for use in human food and livestock feed are Canada and Japan.<br> <br>The stacked hybrid MON863 X MON810 X NK603 expresses two novel insecticidal proteins: Cry3Bb1, a delta-endotoxin which confers resistance to coleopterans such as the Corn Rootworm, and the delta-endotoxin Cry1Ab which confers resistance to lepidopterans, such as the European Corn Borer.  The stacked hybrid also expresses the novel protein CP4 EPSPS which confers glyphosate tolerance.  Cry3Bb1 is produced by the <i>cry</i>3Bb1 gene from MON863, and Cry1Ab, by the <i>cry</i>1Ab gene from MON810.  The CP4 EPSPS protein is produced by the <i>cp4epsps</i> gene from NK603.  The novel traits of each parent line have been combined, using traditional plant breeding methods, to produce this new hybrid.  For a full description of each parent line please refer to the individual product descriptions in the crop database for <a href="dbase.php?action=ShowProd&data=MON863&frmat=LONG"><b>MON863</b></a>, <a href="dbase.php?action=ShowProd&data=MON810&frmat=LONG"><b>MON810</b></a>, and <a href="dbase.php?action=ShowProd&data=NK603&frmat=LONG"><b>NK603</b></a>.<br>The inserted genes and their gene products have a history of safe use, and have undergone review and approval by several regulatory agencies.  No interactions among the gene products or negative synergistic effects are expected in the stacked hybrid.  Neither Cry1Ab, nor Cry3Bb1 are enzymes and therefore have no effect on plant metabolism. The CP4 EPSPS has high affinity for its substrates phosphoenolpyruvate (PEP) and shikimate-3-phosphate, which are part of the shikimate metabolic pathway.  CP4 EPSPS, Cry1Ab and Cry3Bb1 are therefore not expected to interact within, nor affect the metabolism of the stacked hybrid. <br>Studies were conducted to compare the resistance to coleopterans and lepidopterans in the stacked hybrid with each parental line.  There were no statistically significant differences in the levels of resistance to the target insects between the stacked hybrid and either of the parental lines, MON 863 and MON810.  Non-target insects that were found to be unaffected by the insecticidal proteins in MON863 and MON810 were also unaffected by the combination of the proteins in the stacked hybrid.  Thus, the hybridization of MON863 and MON810 did not affect the expression levels of the <i>cry</i>1Ab and <i>cry</i>3Bb genes, and there was no observed synergistic effect of simultaneous exposure to both proteins.  <br>Studies were also conducted to compare the tolerance to glyphosate between the stacked cotton line and each parental line.  There were no significant differences in the tolerance to applications of glyphosate in the stacked line, compared to the parental lines.<br>Heterosis is expected in F1 hybrids.  An example of heterosis is a substantial increase in yield in the F1 hybrid compared to the parental lines.  The stacked hybrid NK603 X MON810 is therefore expected to display heterosis, as would any conventional F1 hybrid.  Heterosis in this hybrid is not expected to be caused by the introduced genes, since the gene products are not expected to interact synergistically.