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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #110290
Title: MOLECULAR MARKERS TO INCREASE CORN EARWORM RESISTANCE IN A MAIZE POPULATION.

Author
item BUTRON, A - SPANISH MINISTRY OF EDU.
item LI, R - UNIV. OF GA
item Guo, Baozhu
item Widstrom, Neil
item SNOOK, M - UNIV. OF GA
item Cleveland, Thomas
item Lynch, Robert

Submitted to: Maydica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2001
Publication Date: 3/14/2001
Citation: Butron, A., Li, R.G., Guo, B., Wilson, D.M., Snook, M.E., Cleveland, T.E., Lynch, R.E. 2001. Molecular markers to increase corn earworm resistance in maize population. Maydica. 46:117-124.

Interpretive Summary: Aflatoxin, a byproduct of mold growth in a wide range of commodities, is considered to be the most potent naturally-occuring carcinogen. These fungi can be found virtually everywhere in the world, but prefer to grow on high nutrient seeds. In the field, corn ear damage due to insects can enable the molds to invade the seeds and contaminate the grain with aflatoxin, expecially in the Southeastern U.S. Thus, the development of strategies to reduce or eliminate aflatoxin contamination in food and fiber is a research priority in ARS. Our efforts on this problem have focused on natural resistance in the host plant by combining different resistant traits together. Maysin, predominantly, and maysin related compounds such as apimaysin 3'-methoxymaysin, and chlorogenic acid have been identified as the most important antibiotic compounds against corn earworm. In this study we intended to obtain molecular markers associated with synthesis of maysin and related compounds in the mapping populations for resistance to Aspergillus flavus. Locus p1, on the short arm of chromosome 1, was identified as a major QTL for synthesis of maysin and related compounds in both populations. The presence of functional allele of p1 is necessary to activate the branch of the flavonoid pathway that leads to maysin, 3' methoxymaysin and apimaysin, and could also affect chlorogenic acid content. Locus p1 alone could be used as a molecular marker to select progenies with high silk maysin or total antibiotic compound in these populations and assists the pyramiding process in order to breed lines with resistance to ear-feeding insects and aflatoxin formation.

Technical Abstract: Maysin, predominantly, and maysin related compounds such as apimaysin, 3' -methoxymaysin, and chlorogenic acid are the most important antibiotic compounds against corn earworm (Helicoverpa zea Boddie). The objective of this work was to obtain molecular markers associated with synthesis of maysin and related compounds in our mapping populations for resistance to Aspergillus flavus. A total 102 probes were used to screen RFLP polymorphisms for two populations, each with 205 and 231 F2 individuals, respectively. F2:3 families were used for evaluation of silk flavonoid content. Locus p1, on the short arm of chromosome 1, was identified as a major QTL for synthesis of maysin and related compounds in both populations. The presence of functional allele of p1 is necessary to activate the branch of the flavonoid pathway that leads to maysin, 3' -methoxymaysin and apimaysin, but could also affect chlorogenic acid content. Locus p1 alone could be used as a molecular marker to select progenies with high silk maysin (above 2%) in these populations. The usefulness of p1 as a marker should be further tested in a wide range of germplasm, and conversion of RFLP-markers into PCR-based markers would make them much more user friendly.