Identification of quantitative trait loci influencing aerial morphogenesis in the model legume Medicago truncatula

• Published in: Theoretical and applied genetics 2007-05, Vol.114 (8), p.1391-1406
• Main Authors: Julier, Bernadette, Huguet, Thierry, Chardon, Fabien, Ayadi, Radia, Pierre, Jean-Baptiste, Prosperi, Jean-Marie, Barre, Philippe, Huyghe, Christian
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cell differentiation, maturation, development, hematopoiesis; Cell physiology; Chromosome 7; Chromosome Mapping; Chromosomes, Plant - genetics; Classical genetics, quantitative genetics, hybrids; CONSTANS (CO) gene; Crops; Digestibility; Dry matter; Flowering Tops - genetics; Flowering Tops - growth & development; Fundamental and applied biological sciences. Psychology; Gene mapping; Genetic diversity; Genetics; Genetics of eukaryotes. Biological and molecular evolution; Inbreeding; Legumes; Life Sciences; Medicago truncatula; Medicago truncatula - anatomy & histology; Medicago truncatula - genetics; Medicago truncatula - growth & development; Molecular and cellular biology; Morphogenesis; Phenotypic variations; Plant Components, Aerial - genetics; Plant Components, Aerial - growth & development; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Stems - genetics; Plant Stems - growth & development; Pteridophyta, spermatophyta; Quantitative Trait Loci; Quantitative Trait, Heritable; Vegetals
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-007-0525-1

In many legume crops, especially in forage legumes, aerial morphogenesis defined as growth and development of plant organs, is an essential trait as it determines plant and seed biomass as well as forage quality (protein concentration, dry matter digestibility). Medicago truncatula is a model species for legume crops. A set of 29 accessions of M. truncatula was evaluated for aerial morphogenetic traits. A recombinant inbred lines (RILs) mapping population was used for analysing quantitative variation in aerial morphogenetic traits and QTL detection. Genes described to be involved in aerial morphogenetic traits in other species were mapped to analyse co-location between QTLs and genes. A large variation was found for flowering date, morphology and dynamics of branch elongation among the 29 accessions and within the RILs population. Flowering date was negatively correlated to main stem and branch length. QTLs were detected for all traits, and each QTL explained from 5.2 to 59.2% of the phenotypic variation. A QTL explaining a large part of genetic variation for flowering date and branch growth was found on chromosome 7. The other chromosomes were also involved in the variation detected in several traits. Mapping of candidate genes indicates a co-location between a homologue of Constans gene or a flowering locus T (FT) gene and the QTL of flowering date on chromosome 7. Other candidate genes for several QTLs are described.