Linkage mapping of domestication loci in a large maize teosinte backcross resource.
An ultimate objective of QTL mapping is cloning genes responsible for quantitative traits. However, projects seldom go beyond segments <5 cM without subsequent breeding and genotyping lines to identify additional crossovers in a genomic region of interest. We report on a QTL analysis performed as a preliminary step in the development of a resource for map-based cloning of domestication and improvement genes in corn. A large backcross (BC)1 population derived from a cross between maize (Zea mays ssp. mays) and teosinte (ssp. parviglumis) was grown for the analysis. A total of 1749 progenies were genotyped for 304 markers and measured for 22 morphological traits. The results are in agreement with earlier studies showing a small number of genomic regions having greater impact on the morphological traits distinguishing maize and teosinte. Despite considerable power to detect epistasis, few QTL interactions were identified. To create a permanent resource, seed of BC1 plants was archived and 1000 BC2S6 BC1-derived lines are in development for fine mapping and cloning. The identification of four BC1 progeny with crossovers in a single gene, tb1, indicated that enough derived lines already exist to clone many QTL without the need to generate and identify additional crossovers.
Briggs
William H
WH
Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA. william.briggs@syngenta.com
McMullen
Michael D
MD
Gaut
Brandon S
BS
Doebley
John
J
D001947:Breeding; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D003434:Crossing Over, Genetic; D004843:Epistasis, Genetic; D035264:Flowers / Q000254:growth & development; D005819:Genetic Markers; D005838:Genotype; D010641:Phenotype; D040641:Quantitative Trait Loci; D013045:Species Specificity; D003313:Zea mays / Q000145:classification / Q000235:genetics* / Q000254:growth & development
D005819:Genetic Markers