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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #57275
Title: ALLELIC FREQUENCY CHANGES IN RESPONSE TO SELECTION FOR RIND PENETROMETER RESISTANCE IN THE MAIZE SYNTHETIC MOSCSSS

Author
item HEREDIA-DIAZ O - UNIV OF MO
item Darrah, Larry
item Coe Jr, Edward
item XU, GUILIN - UNIV OF MO

Submitted to: NCR-167 Corn Breeding Committee Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/23/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The advent of DNA markers and development of RFLP maps allow for the identification and analysis of specific regions of the genome favored through selection. Rind penetrometer resistance (RPR) is a selection criterion successfully used to improve stalk strength in maize. Six cycles of bi-directional recurrent selection for high RPR (HRP), and for low RPR (LRP) have effectively separated a synthetic population into two significantly different sub-populations. Allelic frequencies for 16 RFLP loci, on 12 arms of different chromosomes, across the seven cycles grown (C6 HRP, C4 HRP, C2 HRP, C0, C2 LRP, C4 LRP, and C6 LRP) were analyzed for response to selection. Allelic frequency changes of nine RFLP loci on six chromosome arms, two on 4S, two on 5S, one on 6S, one on 6L, one on 9S, two on 9L, were significantly associated (P<=0.05) with selection for RPR. Significant changes in allelic frequencies were identified at loci mapped near or within regions of the genome where Mendelian factors affecting lignification of the stalk and plant height have been previously mapped. Ninety nine percent of the response to RPR over six cycles of bi- directional selection can be accounted for by a linear model including RFLP loci umc166, bnl15.45, and umc27. Histological analyses of stalks from plants representative of the extremes of selection showed important anatomical differences. High RPR stalks had thicker rind-parenchyma cells interlumen, more angular shape vascular bundles, denser vascular bundle sheath area, and greater deposition of lignin around vascular bundles as compared to LRP stalks.