A linkage map of maize x teosinte Zea luxurians and identification of QTLs controlling root aerenchyma formation

The objectives of this study were to construct a linkage map and identify quantitative trait loci (QTLs) controlling root aerenchyma formation in drained soil conditions using 195 F-2 individuals derived from a cross between maize inbred line B73 x teosinte Zea luxurians. A 107 SSR marker based map covering 1,331 cM across all ten chromosomes was developed. One significant difference between the parents utilized in the study was that under non-flooding conditions, B73 exhibits a minor capacity to develop root aerenchyma, whereas Z. luxurians exhibits a high tendency to form aerenchyma. Linkage analysis indicated segregation distortion regions on chromosomes 2, 4 and 8, and severe recombination suppression on the long arm of chromosome 4. Multiple interval mapping analysis suggests that five QTLs for aerenchyma formation in non-flooding conditions are located on chromosomes 2, 3, 5, 9 and 10, and these explained 36.3% of the total phenotyphic variance. The Z. luxurians alleles in all five QTLs increased the capacity to form aerenchyma and the locations of these QTLs did not overlap those previously identified in the teosinte Z. nicaraguensis. By transferring aerenchyma-forming QTLs from both Z. luxurians and Z. nicaraguensis, it may be possible to pyramid these genes and develop a maize line with exceptional aerenchyma formation and a high level of tolerance to flooding conditions.