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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #79150
Title: GENETIC VARIATION FOR MAYSIN AND TWO OF ITS ANALOGUES IN CROSSES AMONG TWELVE CORN INBREDS

Author
item Widstrom, Neil
item SNOOK, M.

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Chemicals have been identified in corn silks that inhibit growth of the corn earworm larvae, namely maysin, 3'methoxymasin and apimaysin. We studied the inheritance of these compounds to learn how they can be incorporated into silks of corn hybrids grown in the South. Twelve inbred lines and their crosses were evaluated and analyzed using two methods for determining the action of genes controlling concentration of the compound in silks. Differences in concentration were not detected between reciprocal crosses, but large differences among inbreds and crosses were attributable to additive genetic variation. The results suggest that silk concentrations of inbreds would be increased by a simple backcrossing procedure and recurrent selection would be similarly effective in plant populations. One or two inbreds had exceptionally good combining abilities for maysin and sum of 3'methoxymasin plus apimaysin. The concentration of these chemicals are closely related in silks of the lines we tested.

Technical Abstract: The isolation and identification of maysin and 2 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 the corn earworm, Helicoverpa zea (Boddie). This study was initiated to examine the inheritance of these compounds so that a logical course for developing germplasm with high concentrations can be incorporated into corn hybrids for the Southern Corn Belt. Twelve inbred lines were crossed in all combinations and evaluated for maysin and the sum of 3'M+A concentrations in their silks for 2 years. Analysis using Griffing's Method 3 Model I revealed that reciprocal and maternal effects were not significantly different from zero. Subsequent pooling of reciprocal crosses in a Gardner- Eberhart Analysis II gave significant main effects (P < 0.01) and years x entries interactions (P < 0.05). Further partitioning of the variation established additive effects as the predominant source of genetic variation among the 66 crosses evaluated, and that selection for increased maysin and (3'M+A) concentrations in corn silks would be successful through a simple backcrossing procedure or routine recurrent selection within a population. One or 2 inbreds, among the 12 tested, appear to be good candidates for establishing a selection program because they have good general and specific combining ability. Maysin and the sum of its analogues 3'M+A have a close relationship in corn silks (r = 0.81, P < 0.01).