Evolutionary Agroecology: developing high density, communal crop plants for weed suppression and increased sustainability
Wibke Wille,
dept. Agriculture & Ecology, Copenhagen University
Recent advances in our understanding of the role of size differences in competition among plants suggest that the potential for many crops to suppress weed is greater than generally appreciated. Increasing crop density and uniformity of spatial distribution reduces significantly weed growth and increases cereal yield under weed pressure. This potential can be further enhanced by developing varieties for such an environment, allowing farmers to drastically reduce or eliminate herbicides and energy-intensive forms of weed control.
One hypothesis is that certain forms of phenotypic plasticity that increase individual fitness, specifically the “shade avoidance response”, reduce the potential for weed suppression and high yield in high-density high-uniformity cereal cultivation systems. To test this hypothesis we have grown chemically mutated seeds of spring wheat under green shading selecting for plants deficient in shade avoidance as a potential source of genes to be introduced into high-yielding varieties for crowded, spatially-uniform cropping systems.
A second hypothesis is that there is a large potential for high-density weed-suppressing wheat ideotypes in the existing wheat germplasm, though the genetic characteristics optimizing this potential may have been lost over the past century of breeding cereals grown in rows at low density with mechanical or chemical weed control. We are testing this by growing a large collection of wheat lines from international cultivars and landraces in our high-density high-uniformity system to seek and document natural variation in weed suppression under these conditions.
Wibke Wille,
dept. Agriculture & Ecology, Copenhagen University
Recent advances in our understanding of the role of size differences in competition among plants suggest that the potential for many crops to suppress weed is greater than generally appreciated. Increasing crop density and uniformity of spatial distribution reduces significantly weed growth and increases cereal yield under weed pressure. This potential can be further enhanced by developing varieties for such an environment, allowing farmers to drastically reduce or eliminate herbicides and energy-intensive forms of weed control.
One hypothesis is that certain forms of phenotypic plasticity that increase individual fitness, specifically the “shade avoidance response”, reduce the potential for weed suppression and high yield in high-density high-uniformity cereal cultivation systems. To test this hypothesis we have grown chemically mutated seeds of spring wheat under green shading selecting for plants deficient in shade avoidance as a potential source of genes to be introduced into high-yielding varieties for crowded, spatially-uniform cropping systems.
A second hypothesis is that there is a large potential for high-density weed-suppressing wheat ideotypes in the existing wheat germplasm, though the genetic characteristics optimizing this potential may have been lost over the past century of breeding cereals grown in rows at low density with mechanical or chemical weed control. We are testing this by growing a large collection of wheat lines from international cultivars and landraces in our high-density high-uniformity system to seek and document natural variation in weed suppression under these conditions.
