Genetic and environmental dissection of biomass accumulation in multi-genotype maize canopies.

Tsu-Wei Chen,Christophe Pradal,Simon Artzet,Llorenç Cabrera-Bosquet,Raphaël Perez,Santiago Alvarez Prado,Aude Coupel-Ledru,Christian Fournier,François Tardieu

doi:10.1093/jxb/ery309

Abstract

Multi-genotype canopies are frequent in phenotyping experiments and are of increasing interest in agriculture. Radiation interception efficiency (RIE) and radiation use efficiency (RUE) have low heritabilities in such canopies. We propose a revised Monteith equation that identifies environmental and genetic components of RIE and RUE. An environmental term, a component of RIE, characterizes the effect of the presence or absence of neighbours on light interception. The ability of a given plant to compete with its neighbours is then identified, which accounts for the genetic variability of RIE of plants having similar leaf areas. This method was used in three experiments in a phenotyping platform with 765 plants of 255 maize hybrids. As expected, the heritability of the environmental term was near zero, whereas that of the competitiveness term increased with phenological stage, resulting in the identification of quantitative trait loci. In the same way, RUE was dissected as an effect of intercepted light and a genetic term. This approach was used for predicting the behaviour of individual genotypes in virtual multi-genotype canopies. A large effect of competitiveness was observed in multi-genotype but not in single-genotype canopies, resulting in a bias for genotype comparisons in breeding fields.

Highlights

Light interception is a main determinant of the genetic variability of biomass accumulation, together with photosynthetic rate (Zhu et al, 2010; Reynolds et al, 2012)
We have first defined radiation interception efficiency at the plant level (RIEplant) as the ratio of the amount of light intercepted by a plant to the amount of incident light summed over a spatial domain centred on the plant and whose area equals the space allocated to each plant, i.e. the reciprocal of plant density
The non-uniform competition pressure (CP) inside the canopy reflects the fact that the relationship between LA and Radiation interception efficiency (RIE) is not linear, so the ratio tends to increase for higher leaf area in the considered window

Summary

Introduction

Light interception is a main determinant of the genetic variability of biomass accumulation, together with photosynthetic rate (Zhu et al, 2010; Reynolds et al, 2012). It is essentially linked to leaf area, itself subjected to tight genetic and environmental controls (Tardieu et al, 2014), but plant architecture largely contributes to light interception and plant performance as suggested by the success of breeding programmes affecting leaf erectness (Mantilla-Perez and Salas Fernandez, 2017).

Methods

Results

Conclusion