Increasing Crop Yields by Breeding Plants to Cooperate
Published:09 Jan.2023    Source:PLOS
A simple breeding experiment, combined with genetic analysis, can rapidly uncover genes that promote cooperation and higher yields of plant populations, according to a new study publishing November 29 in the open access journal PLOS Biology, by Samuel Wuest of the University of Zurich and Agroscope, Switzerland, and colleagues. The results have the potential to quickly increase crop productivity through conventional breeding methods.
In classic evolutionary theory, individuals compete, and those with the most competitively advantageous genes create more offspring that bear the same winning genes. This poses a challenge for plant breeders, who are often faced with selecting plants that cooperate, rather than compete. In a dense monoculture stand of corn or wheat, overall yield may be improved if individuals avoid growing too tall or spreading their leaves too wide (the "Green Revolution" of the mid-20th century was largely dependent on the introduction of dwarfing alleles into major cereal grains).
Discovering the alleles (versions of genes that differ between individuals) that may promote cooperation is challenging, but the authors designed a system to reveal them. In alignment with game theory, the authors reasoned that the most cooperative genotype will perform best with similarly cooperative neighbors, but will do poorly when facing selfish, highly competitive neighbors. They used the model plant Arabidopsis to compare the performance of a given plant when grown with another genetically similar individual (modeling a monoculture) to its performance when grown with a set of "tester" genotypes, that varied in their growth strategies. By determining both the overall vigor of each plant (as measured by above-ground biomass) and the difference between its growth in the two situations, they could see which plants maximized both the ability to grow rapidly and the ability to cooperate with genetically similar individuals so that their neighbors also grew well.