QTLs for the elongation of axile and lateral roots of maize in response to low water potential

• Published in: Theoretical and applied genetics Vol. 120; no. 3; pp. 621 - 631
• Main Authors: Ruta, N., Liedgens, M., Fracheboud, Y., Stamp, Peter, Hund, A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2010; Springer; Springer Nature B.V
• Subjects: Agriculture; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Classical genetics, quantitative genetics, hybrids; Corn; Drought; Drought resistance; Fundamental and applied biological sciences. Psychology; Genetic aspects; Genetics of eukaryotes. Biological and molecular evolution; Growth; Identification and classification; Life Sciences; Models, Genetic; Original Paper; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant Roots - anatomy & histology; Plant Roots - drug effects; Plant Roots - genetics; Plant Roots - growth & development; Plant-water relationships; Population Dynamics; Pteridophyta, spermatophyta; QTL; Quantitative trait loci; Quantitative Trait Loci - genetics; Root growth; Roots (Botany); Triticum aestivum; Vegetals; Water - pharmacology; Water potential; Zea mays; Zea mays - drug effects; Zea mays - genetics; Zea mays - growth & development; Zea mays L; Drought resistance; Root growth; QTL; Corn; Drought; Water potential; L; Agronomic character; Root; Quantitative character; Lateral; Genetics; Agriculture; Elongation
• ISSN: 0040-5752; 1432-2242; 1432-2242
• DOI: 10.1007/s00122-009-1180-5

Changes in root architecture and the maintenance of root growth in drying soil are key traits for the adaptation of maize ( Zea mays L.) to drought environments. The goal of this study was to map quantitative trait loci (QTLs) for root growth and its response to dehydration in a population of 208 recombinant inbred lines from the International Maize and Wheat Improvement Center (CIMMYT). The parents, Ac7643 and Ac7729/TZSRW, are known to be drought-tolerant and drought-sensitive, respectively. Roots were grown in pouches under well-watered conditions or at low water potential induced by the osmolyte polyethylene glycol (PEG 8000). Axile root length ( L Ax ) increased linearly, while lateral root length ( L Lat ) increased exponentially over time. Thirteen QTLs were identified for six seedling traits: elongation rates of axile roots (ER Ax ), the rate constant of lateral root elongation ( k Lat ), the final respective lengths ( L Ax and L Lat ), and the ratios k Lat /ER Ax and L Lat / L Ax. While QTLs for lateral root traits were constitutively expressed, most QTLs for axile root traits responded to water stress. For axile roots, common QTLs existed for ER Ax and L Ax . Quantitative trait loci for the elongation rates of axile roots responded more clearly to water stress compared to root length. Two major QTLs were detected: a QTL for general vigor in bin 2.02, affecting most of the traits, and a QTL for the constitutive increase in k Lat and k Lat /ER Ax in bins 6.04–6.05. The latter co-located with a major QTL for the anthesis-silking interval (ASI) reported in published field experiments, suggesting an involvement of root morphology in drought tolerance. Rapid seedling tests are feasible for elucidating the genetic response of root growth to low water potential. Some loci may even have pleiotropic effects on yield-related traits under drought stress.