Light sharing within virtual wheat-pea mixtures was influenced by the variability of
pea’s architectural parameters affecting LAI and height. Light capture was affected
by the development of leaflets, number of branches and phytomers and internode length.
Background and aims
Light interception is a key factor driving the functioning of wheat–pea
intercrops. The sharing of light is related to the canopy structure, which results from
the architectural parameters of the mixed species. In the present study, we
characterized six contrasting pea genotypes and identified architectural parameters
whose range of variability leads to various levels of light sharing within virtual
Virtual plants were derived from magnetic digitizations performed during the growing
cycle in a greenhouse experiment. Plant mock-ups were used as inputs of a radiative
transfer model in order to estimate light interception in virtual wheat–pea
mixtures. The turbid medium approach, extended to well-mixed canopies, was used as a
framework for assessing the effects of leaf area index (LAI) and mean leaf inclination
on light sharing.
Three groups of pea genotypes were distinguished: (i) early and leafy cultivars, (ii)
late semi-leafless cultivars and (iii) low-development semi-leafless cultivars. Within
open canopies, light sharing was well described by the turbid medium approach and was
therefore determined by the architectural parameters that composed LAI and foliage
inclination. When canopy closure started, the turbid medium approach was unable to
properly infer light partitioning because of the vertical structure of the canopy. This
was related to the architectural parameters that determine the height of pea genotypes.
Light capture was therefore affected by the development of leaflets, number of branches
and phytomers, as well as internode length.
This study provides information on pea architecture and identifies parameters whose
variability can be used to drive light sharing within wheat–pea mixtures. These
results could be used to build up the architecture of pea ideotypes adapted to
multi-specific stands towards light competition.