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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #64812
Title: ALLELIC FREQUENCY CHANGES IN THE MOSCSSS MAIZE SYNTHETIC IN RESPONSE TO BI-DIRECTIONAL RECURRENT SELECTION FOR RIND PENETROMETER RESISTANCE

Author
item HEREDIA-DIAZ, OSCAR - U OF MO ; MYCOGEN PLANT
item ALSIRT, A - U OF MO; CARGILL SEEDS
item Darrah, Larry
item Coe Jr, Edward

Submitted to: Maydica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Stalk lodging continues to be a major limiting factor in production of maize. Production under intensive conditions, including high plant density and soil fertility, often results in increased stalk lodging. Selecting populations by using a stalk rind penetrometer has improved stalk strength. Use of DNA markers allowed identification and quantification of specific chromosome regions favored by selection with the rind penetrometer. Following six cycles of selection, changes observed in the frequency of nine DNA markers on 12 arms of different chromosomes were significantly associated with selection for rind penetrometer resistance. Analysis and dissection of complex traits, like stalk strength, are of interest to the maize breeder in that high yielding hybrids require relatively strong stalks, but not so much in excess that competition with grain yield occurs. The use of DNA markers to identify specific chromosomal regions responsible efor stalk strength will allow a better understanding and more efficient manipulation of this trait.

Technical Abstract: Stalk lodging continues to be a limiting factor in maize production. Intensive cropping practices, including high plant density and fertility, often result in increased stalk lodging. The stalk rind penetrometer has been successfully used to improve stalk strength. Use of DNA markers allows identification and analysis of specific regions of the genome favored by phenotypic selection. Objectives of this study were: i) to identify frequency changes associated with DNA markers in a synthetic maize population following six cycles of bi-directional selection for rind penetrometer resistance (RPR), ii) to identify chromosomal regions associated with RPR and correlated responses to selection for RPR, and iii) to find predictive models for DNA marker frequency changes in response to selection for RPR. Frequency changes of nine DNA markers were significantly associated with selection for RPR. Chi-square tests were used to determine whether observed changes in DNA marker frequencies acros cycles of selection were due to direct selection or other causes. Eight loci were identified as having changed in response to selection under these tests. Ninety-nine percent of the response to RPR over six cycles of bi-directional selection was accounted for by a linear model including DNA markers umc166, bnl15.45, and umc27. The identification of chromosomal regions responsible for stalk strength will allow better understanding and manipulation of this stalk trait.