GENETICS OF ANTIBIOTIC-RESISTANCE IN CORN SILKS TO THE CORN-EARWORM (LEPIDOPTERA, NOCTUIDAE)

Antibiotic resistance in com, Zea mays L., silks results in the production of small larvae of Helicoverpa zea (Boddie), extends the development period and reduces the fecundity of the pest insect. The genetic basis of the antibiotic silk resistance was studied using silks from individual plants of resistant and susceptible inbreds and progeny in six generations (P1, P2, F1, F2, BC1, and BC2). Results of the scaling and chi-square tests for 'Ab18 (susceptible) x Zapalote Chico' (resistant) and 'GT114 (resistant) x GT119' (susceptible) indicated the additive-dominance model was unsatisfactory. The nature of the underlying genetic control of the antibiotic silk resistance to corn earworm in the two crosses appears to be more complicated and perhaps controlled by several pairs of genes at different loci.