1. Vegetative development : the morphogenesis of plant organs -- 2. Carbon acquisition at the crop level in pea -- 3. Dilution curve -- 4. Carbon and nitrogen fluxes within the plant -- 5. The seed number -- 6. Abiotic stresses -- 7. Biotic stresses -- 8. A model which integrates knowledge on pea crop physiology and agronomic diagnosis -- 9. Proposal for a diagnostic approach to analyse yield variations in peas -- 10. Genotype x environment interaction for yield and protein concentration.