title: Root-ABA1, a major constitutive QTL, affects maize root architecture and leaf ABA concentration at different water regimes.
abstract: Near-isogenic hybrids (NIHs), developed from crossing maize (Zea mays L.) backcross-derived lines (BDLs) differing for the parental alleles at a major QTL for leaf ABA concentration (L-ABA), were field-tested for 2 years under well-watered and water-stressed conditions. Differences among NIHs for L-ABA and other morpho-physiological traits were not affected by water regimes. On average, the QTL allele for high L-ABA markedly reduced stomatal conductance and root lodging. To elucidate the effects of the QTL on root architecture and L-ABA, root traits of two pairs of BDLs were measured in plants grown in soil columns at three water regimes. Differences among BDLs were not affected by water regimes. Across water regimes, the QTL confirmed its effect on L-ABA and showed a concurrent effect on root angle, branching, number, diameter, and dry weight. Based on these results, it is concluded that the QTL affects root lodging through a constitutive effect on root architecture. In addition, there is speculation that the QTL effects on root traits and L-ABA are probably due to pleiotropy rather than linkage and a model is proposed in which the QTL has a direct effect on root architecture, while indirectly affecting L-ABA.
authors.affiliation: Department of Agroenvironmental Science and Technology (DISTA), University of Bologna, Viale Fanin 44, I-40127 Bologna, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Giuliani
authors.forename: Maria Corinna
authors.initials: MC
authors.lastname: Sanguineti
authors.forename: Roberto
authors.initials: R
authors.lastname: Tuberosa
authors.forename: Massimo
authors.initials: M
authors.lastname: Bellotti
authors.forename: Silvio
authors.initials: S
authors.lastname: Salvi
authors.forename: Pierangelo
authors.initials: P
authors.lastname: Landi
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D003433:Crosses, Genetic; D006824:Hybridization, Genetic; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D014867:Water; D000040:Abscisic Acid