Comparison of the morphogenesis of three genotypes of pea (Pisum sativum) grown in pure stands and wheat-based intercrops

In intercropping systems, plant morphology highly determines the amount of resources captured by each component species. However, morphogenesis of cultivated species has been mainly described in mono-specific growing conditions, although plasticity can occur in multi-specific stands. This paper reports on the variability of the morphogenesis of three pea genotypes grown in pure stands and mixed with wheat. Most morphogenetic parameters of pea were dependent on the genotype. However, there was low variability of pea morphogenesis between sole and mixed stands, except for plant height and branching of the long cycle cultivar.

Cereal–legume intercrops represent a promising way of combining high productivity and agriculture sustainability. The benefits of cereal–legume mixtures are highly affected by species morphology and functioning, which determine the balance between competition and complementarity for resource acquisition. Studying species morphogenesis, which controls plant architecture, is therefore of major interest. The morphogenesis of cultivated species has been mainly described in mono-specific growing conditions, although morphogenetic plasticity can occur in multi-specific stands. The aim of the present study was therefore to characterize the variability of the morphogenesis of pea plants grown either in pure stands or mixed with wheat. This was achieved through a field experiment that included three pea cultivars with contrasting earliness (hr and HR type) and branching patterns. Results show that most of the assessed parameters of pea morphogenesis (phenology, branching, final number of vegetative organs and their kinetics of appearance) were mainly dependent on the considered genotype, which highlights the importance of the choice of cultivars in intercropping systems. There was however a low variability of pea morphogenesis between sole and mixed stands except for plant height and branching of the long-cycle cultivar. The information provided in the present study at stand and plant scale can be used to build up structural–functional models. These models can contribute to improving the understanding of the functioning of cereal–legume intercrops and also to the definition of plant ideotypes adapted to the growth in intercrops.