Phenotyping progenies for complex architectural traits: a strategy for 1-year-old apple trees (Malus x domestica Borkh.)

Abstract

International audienceThe aim of this study was to define a methodology for describing architectural traits in a quantitative way on tree descendants. Our strategy was to collect traits related to both tree structural organization, resulting from growth and branching, and tree form and then to select among these traits relevant descriptors on the basis of their genetic parameters. Because the complexity of tree architecture increases with tree age, we chose to describe the trees in the early stages of development. The study was carried out on a 1-year-old apple progeny derived from two parent cultivars with contrasted architecture. A large number of variables were collected at different positions and scales within the trees. Broad-sense heritability and genetic correlations were estimated and the within tree variability was analyzed for variables measured on long sylleptic axillary shoots (LSAS). These results were combined to select heritable and not correlated variables. Finally, the selection of variables proposed combines topological with geometric traits measured on both trunks and LSAS: (1) on the trunk, mean internode length, and number of sylleptic axillary shoots; (2) on axillary shoots, conicity, bending, and number of sylleptic axillary shoots born at order 3. The trees of the progeny were partitioned on the basis of these variables. The putative agronomic interest of the selected variables with respect to the subsequent tree development is discussed

Comparison of tree architecture using tree edit distances: application to 2-year-old apple hybrids

“…The 50 genotypes were replicated three times by grafting onto 'Pajam 1' rootstock. These 150 trees were implanted in March, 2003 at the Melgueil INRA experimental station (Segura et al 2006). …”

“…This sub-sample was selected from a partition of the whole population obtained from the following heritable and uncorrelated quantitative traits: number of axes per tree, mean diameter of the second annual growth of the trunk, trunk mean internode length, LPAS conicity and LSAS orientation (Segura et al 2006). On the basis of these traits, hybrids were clustered into six groups and the three trees at the centre of each group were selected to constitute a sub-sample of 18 trees.…”

“…From a fine phenotyping at a juvenile stage, we have already shown that many geometric and topological traits displayed high heritability and strong genetic control (Segura et al 2006(Segura et al , 2007. Moreover, to investigate how the architectural traits segregate and recombine within progenies and to contribute to the definition of architectural ideotypes (Lespinasse 1992;Dickman et al 1994), several apple classifications have already been proposed.…”

“…This classification displayed a continuum from trees with a few short branches to trees with many long branches. We have also proposed a classification of 1-year-old apple hybrids on the basis of heritable and uncorrelated traits (Segura et al 2006). However, in these studies, the topological organisation of the trees was poorly exploited.…”

Reconstrução de maquetes 3D e manipulação da arquitetura de espécies perenes cultivadas no Brasil

“…Godin (2000) define a arquitetura vegetal como "qualquer descrição individual baseada na decomposição de plantas em componentes, que especifica o seu tipo biológico, sua forma, sua localização/orientação no espaço e a maneira como eles são fisicamente relacionados uns aos outros". A análise topológica dos módulos vegetais e de sua distribuição espacial (topológico-geométrica) aplica métodos estatístico-matemáticos complexos na avaliação de suas inter-relações (Louarn et al, 2007), e define as leis botânicas na determinação de maneiras de construção da arquitetura vegetal (Costes & Guedon, 2002) ou de variabilidade genética e arquitetura vegetal (Segura et al, 2007). Além disso, a modelagem funcional-estrutural agrupa diversas combinações entre os modelos baseados nos processos ecofisiológicos (alocação de carbono, transporte de água etc.)…”