Combining Quantitative Trait Loci Analysis and an Ecophysiological Model to Analyze the Genetic Variability of the Responses of Maize Leaf Growth to Temperature and Water Deficit

• Published in: Plant physiology (Bethesda) 2003-02, Vol.131 (2), p.664-675
• Main Authors: Matthieu Reymond, Muller, Bertrand, Agnès Leonardi, Alain Charcosset, Tardieu, François
• Format: Article
• Language: English
• Subjects: Abscisic Acid - metabolism; Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Biological and medical sciences; Chromosomes; Corn; Crosses, Genetic; Ecology; Ecophysiology; Fundamental and applied biological sciences. Psychology; Gene mapping; Genetic Variation; Genetics; Genetics and breeding of economic plants; Growth chambers; Leaves; Life Sciences; Meristem - growth & development; Meristems; Modeling; Models, Biological; Moisture content; Parametric models; Plant Leaves - drug effects; Plant Leaves - genetics; Plant Leaves - growth & development; Plants; Plants genetics; Quantitative trait loci; Quantitative Trait Loci - genetics; Recombination, Genetic; Soil - analysis; Soil water; Soil water deficit; Temperature; Vapor pressure; Varietal selection. Specialized plant breeding, plant breeding aims; Water - pharmacology; Water deficit; Water vapor; Whole Plant and Ecophysiology; Zea mays - drug effects; Zea mays - genetics; Zea mays - physiology
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.013839

Ecophysiological models predict quantitative traits of one genotype in any environment, whereas quantitative trait locus (QTL) models predict the contribution of alleles to quantitative traits under a limited number of environments. We have combined both approaches by dissecting into effects of QTLs the parameters of a model of maize (Zea mays) leaf elongation rate (LER; H. Ben Haj Salah, F. Tardieu [1997] Plant Physiol 114: 893-900). Response curves of LER to meristem temperature, water vapor pressure difference, and soil water status were established in 100 recombinant inbred lines (RILs) of maize in six experiments carried out in the field or in the greenhouse. All responses were linear and common to different experiments, consistent with the model. A QTL analysis was carried out on the slopes of these responses by composite interval mapping confirmed by bootstrap analysis. Most QTLs were specific of one response only. QTLs of abscisic acid concentration in the xylem sap colocalized with QTLs of response to soil water deficit and conferred a low response. Each parameter of the ecophysiological model was computed as the sum of QTL effects, allowing calculation of parameters for 11 new RILs and two parental lines. LERs were simulated and compared with measurements in a growth chamber experiment. The combined model accounted for 74% of the variability of LER, suggesting that it has a general value for any RIL under any environment.