Development of sweet corn hybrids having resistance to ear feeding by the European corn borer (ECB) (Ostrinia nubilalis, Hübner) would save growers millions of dollars annually. Sweet corn breeding lines have been developed which show resistance to ear feeding. To determine whether resistance in these lines was heritable, testcrosses were made between 6 resistant lines and 2 susceptible inbreds. The testcrosses, resistant lines, susceptible inbreds, and Jubilee, a standard susceptible hybrid, were planted in randomized complete blocks replicated 8 times at each of 2 locations. Primary ears were infested, on the ear tip, at mid-silk (R3) with approximately 50 neonate larvae and were evaluated for damage 25 - 30 days later using a 9 point scale. The resistant parents and their testcrosses had 15% to 64% more resistant ears (less than 1% kernel damage at the tip only) than Jubilee. The inbreds and their commercial hybrid did not differ in resistance from Jubilee. Resistance to ECB appears to be polygenic and it has been suggested that some level of non-additive gene action is important. While the specific traits responsible for ear resistance are not known, the resistance of the breeding lines was transmitted to the testcrosses.
SWEET CORN EAR RESISTANCE TO THE EUROPEAN CORN BORER (Ostrinia nubilalis, Hubner) AND ITS RESPONSE IN SINGLE CROSSES.