Ideotype construction from an architectural model of pea
Résumé
There is an increasing need for growing legume species in Europe in order to reduce dependency on
imported vegetable proteins. Currently, pea (Pisum sativum) is the principle source of vegetable
proteins. However, the productivity rate of pea crop is still under its potential mainly due to fungal
foliar diseases. The most damaging ones are caused by Ascochyta pisi, Mycosphaerella pinodes and
Phoma medicaginis.
Dynamics of such diseases have been shown to depend on plant architecture e.g. Leaf Area Index
(LAI), plant height, internode length (Le May et al., 2009). Virtual models of canopy architecture
therefore appear as suitable tools for studying and modelling plant–pathogen interactions and diseases
dispersal.
We have developed a 3D architectural model of pea growth based on the L-system formalism and
developed on the L-Py platform (Boudon et al., 2010). Initial parameters were based on data from a
field-grown crop of winter pea cv Lucy. The above ground architecture is represented as a succession
of phytomers emitted by main stems and branches. Phytomers are considered as a collection of organs
encoded as modules that support their state i.e. age, length, topology and geometry. The rate of
phytomer emission was set for main stems and branches. The number of branches and their time of
emergence are attributes of each node of stems.
Coupled with epidemiologic models, this simulator can be used as a conceptual framework for
studying the effects of pea architectural parameters on disease development and dispersal. Indeed, the
present model is able to build contrasted canopies of ideotypes with regard to LAI and its spatial
distribution (plant density, phytomer number, branching ability, axis orientation, leaf growth), plant
height (internode growth), foliage orientation (leaf geometry) and dynamics of growth (rate of
phytomers and branch emission, organ growth kinetics). Moreover, the formalism chosen in the
present study also allows to assess the benefits of intercropping systems, comprising pea-wheat
mixtures, towards disease pressure such as the wheat/Septoria tritici pathosystem (Robert et al., 2008).
Domaines
Biologie végétale
Fichier principal
BarillotR-ECA_1.pdf (22.88 Ko)
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24_L-pea_ECA_030712_3.pdf (2.1 Mo)
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ECA_2012_2.pdf (65.64 Ko)
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