QTL mapping of above-ground adventitious roots during flooding in maize x teosinte "Zea nicaraguensis" backcross population

Abstract

Quantitative trait locus (QTL) analyses were performed to map the genes controlling adventitious root formation on the soil surface (ARF-SS) under flooding conditions in seedlings of 317 BC₃F₁ individuals derived from a cross between elite maize Mi29 x teosinte Zea nicaraguensis. An SSR-based linkage map was developed using 94 markers, covering 896.3 cM of the ten chromosomes. The ability of ARF-SS under flooding conditions showed continuous variation in the BC₃F₁ population. By single point regression and interval mapping analyses, the QTLs for ARF-SS were located on chromosomes 3 (bin 3.04), 7 (bin 7.04) and 8 (bin 8.03). Alleles of Z. nicaraguensis, which has a high ability of ARF-SS, increased the level of ARF-SS for all the QTLs. By comparing chromosome positions of ARF-SS loci to previously reported loci, the region on chromosome 3 was shown to be unique to this teosinte. A possible application of the new QTL to breed flooding tolerant maize is discussed.