GENETIC-VARIATION FOR MAYSIN AND ITS ANALOGS IN CROSSES AMONG CORN INBREDS

The isolation and identification of maysin and two of its analogues, 3 '-methoxymaysin and apimaysin (3'M+A), in the silks of corn, Zea mays L., has given plant breeders a new tool for reducing damage by larvae of the corn earworm, Nelicoverpa tea (Boddie). This study was initiate d to examine the inheritance of these compounds so that a logical cour se for developing germplasm with high concentrations can be determined . Incorporation of the compounds into corn hybrids for the southern US A can then proceed. Twelve inbred lines were crossed in all combinatio ns and evaluated for maysin and the sum of 3'-methoxymaysin plus apima ysin concentrations in their silks. Analysis of data from 2 yr by Grim ing's Method 3 Model I revealed that reciprocal and maternal effects m ere not significantly different from zero. Subsequent pooling of recip rocal crosses in a Gardner-Eberhart Analysis If gave significant main effects (P < 0.01) and Sears x entries interactions (P < 0.05). Furthe r partitioning of the variation established additive effects as the pr edominant source of genetic variation among the 66 crosses evaluated. Selection for increased maysin and (3'-methoxymaysin plus apimaysin) c oncentrations in corn silks should be successful by means of a simple backcrossing procedure or routine recurrent selection within a populat ion. One or two inbreds, among the 12 tested, appear to be good candid ates for establishing a selection program because they have both good general and specific combining ability. Maysin concentration and the s um of its analogues 3'-methoxymaysin and apimaysin are closely correla ted in corn silks (r = 0.81, P < 0.01).