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Drought stress and tropical maize: QTL-by-environment interactions and stability of QTLs across environments for yield components and secondary traits

Messmer, Rainer ; Fracheboud, Yvan ; Bänziger, Marianne ; Vargas, Mateo ; Stamp, Peter ; Ribaut, Jean-Marcel

In: Theoretical and Applied Genetics, 2009, vol. 119, no. 5, p. 913-930

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    Title
    • Drought stress and tropical maize: QTL-by-environment interactions and stability of QTLs across environments for yield components and secondary traits
    Author
    • Messmer, Rainer. ETH Zurich, Institute of Plant Sciences, Universitaetstrasse 2, 8092, Zurich, Switzerland
    • Fracheboud, Yvan. ETH Zurich, Institute of Plant Sciences, Universitaetstrasse 2, 8092, Zurich, Switzerland
    • Bänziger, Marianne. International Maize and Wheat Improvement Center (CIMMYT), Village Market-00621 ICRAF House, United Nations Avenue, P.O. Box 1041, Nairobi, Kenya
    • Vargas, Mateo. International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600, Mexico, DF, Mexico
    • Stamp, Peter. ETH Zurich, Institute of Plant Sciences, Universitaetstrasse 2, 8092, Zurich, Switzerland
    • Ribaut, Jean-Marcel. Generation Challenge Programme, International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600, Mexico, DF, Mexico
    Document Type
    • Postprint
    Classification
    • Agriculture, Agronomy
    OAI-PMH Identifier
    • oai:doc.rero.ch:314410
    Summary
    A recombinant inbred line (RIL) population was evaluated in seven field experiments representing four environments: water stress at flowering (WS) and well-watered (WW) conditions in Mexico and Zimbabwe. The QTLs were identified for each trait in each individual experiment (single-experiment analysis) as well as per environment, per water regime across locations and across all experiments (joint analyses). For the six target traits (male flowering, anthesis-to-silking interval, grain yield, kernel number, 100-kernel fresh weight and plant height) 81, 57, 51 and 34 QTLs were identified in the four step-wise analyses, respectively. Despite high values of heritability, the phenotypic variance explained by QTLs was reduced, indicating epistatic interactions. About 80, 60 and 6% of the QTLs did not present significant QTL-by-environment interactions (QTL×E) in the joint analyses per environment, per water regime and across all experiments. The expression of QTLs was quite stable across years at a given location and across locations under the same water regime. However, the stability of QTLs decreased drastically when data were combined across water regimes, reflecting a different genetic basis of the target traits in the drought and well-watered trials. Several clusters of QTLs for different traits were identified by the joint analyses of the WW (chromosomes 1 and 8) and WS (chromosomes 1, 3 and 5) treatments and across water regimes (chromosome 1). Those regions are clear targets for future marker-assisted breeding, and our results confirm that the best approach to breeding for drought tolerance includes selection under water stress