Adel-maize and Adel wheat as tools for simulating the dynamics of 3D canopies

1. Adel-maize and Adel wheatas tools for simulating the dynamics of 3D canopies Bruno Andrieu and Christian Fournier INRA, UMR EGC 78850 Thiverval-Grignon Bruno.andrieu@grignon.inra.fr Christian.Fournier@grignon.inra.fr

2. Why models of plant architecture ? • Component of FSPMs • Tools to simulate the time curse of 3D canopy structure • Modelling the environment perceived by individual plant organs • Improving prediction of statistical variables • Intermediate approachs : eg 3D models interfaced with crop models

3. Specific aspects • Kinetics of development, extension and senescence of individual plant organs • Patterns of size of mature blade, sheaths, internodes • 3D geometry • Leaf geometry and orientation • Axe orientation

4. Adel-maize

5. Scheme of development

6. Schedule of organ extension

7. Size of mature leaves along the shoot

8. cx²+dy²+e=0 Ax²+bx Parametrisation of midrib curvature Phi ? Prévot et al, 1991

9. Measured vs simulated light interception

10. Exemple of application B. Andrieu, G. Popa, Y. Sohbi, C. Fournier • A field experiment was reproduced in silico, enabling incident PAR to be calculated for all individual leaf Final width of all laminas above 4 could be interpreted as the product of two simple functions : Wmax =f(n) *f(E) f(n) f(E) # ln(E) • Thus response of width of lamina to density appear to be a function of local light availability.

11. In progress • Ability to simulate a range of contrasted genotypes • More generic description of leaf geometry • Investigation on plasticity of architecture under contrasted environmental conditions (density, cold). Still far from mechanistic simulation But good progress in identifying the degree of freedom

12. Wheat architecture f8 f11 f 12 f 7 f7 f7 f 8 f 9 f 6 f 6 f 8 PHYTOMERE Entre-nœud T1 T1 Feuille T0 T0 Bourgeon axillaire D 250 D 70

13. Size of matures laminae along the shoot D 70 D 70 35 35 bm 30 t1 30 t2 25 t3 25 t4 20 t5 T0 20 t6 T1 Length of laminae (cm) 15 Length of laminae (cm) T2 15 T3 10 T4 10 T5 5 T6 5 0 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Relative phytomer number Phytomer

14. A unique shift applies to laminae, sheath and internodes

15. Kinetics of leaf extension follows a single pattern along the shoot See also Fournier et al New Phytol 2005

16. Prevot et al (1991) maize leaf fitted to wheat leaves

17. See also Fournier et al 2003 in PMA03 Evers et al, New Phytol 2005

18. In progress • with UCL (J. Watt, J. Hillier, P. Lewis) • Multi-genotype version • Duration of leaves • Use in Remote sensing • With WUR (J. Evers, J. Vos) • Extension to spring wheat • Tillering • Incorporating photosynthesis

19. After J. Watt Blade length Sheath length Internode length

20. To be further investigated • Still few is known about the quality of 3D representation for RT investigations • Tropism, shade avoidance <-> clumping • How far can we decrease the number in model parameters (due to low RT sensitivity, or stable patterns) • eg in describing leaf shape (in progress) • Genericity over a range of genotypes, species

21. Remaining to be modelled • Distribution and time curse of leaf exchange properties (Cab, H20, etc ..) and death to drive a leaf reflectance model • How kinetics of extension and mature size of organs is driven by environment (H20, Nitrogen, density) • Ear development and optical properties

22. In progress • with UCL (J. Watt, J. Hillier, P. Lewis) • Multi-genotype version • Duration of leaves • Use in Remote sensing • With WUR (J. Evers, J. Vos) • Extension to spring wheat • Tillering • Incorporating photosynthesis