Uncovering the genetic basis of competitiveness, and the potential for cooperation, in plant groups

Crop productivity was transformed by incorporating dwarfing genes that made plants smaller and less competitive (more cooperative). Beyond such major shifts in plant size, however, it is not clear how much variation in competitiveness remains and how to find its genetic basis. We performed plant density experiments, using 484 lines of the Arabidopsis thaliana Multi-parent Advanced Generation Inter-Cross (MAGIC) population, to compare methods for mapping the genetic basis of plant competitiveness. We first found that a major dwarfing gene, the erecta allele, caused reduced competitiveness and higher group productivity. Then, measuring competitiveness more generally, we found: (i) extensive variation in generic measures of competitiveness that extended beyond the effects of the erecta allele; (ii) a novel genomic region underlying variation in competitiveness; and (iii) that some measures of competitiveness were more useful than others. Our results show how modern genomic resources, including multi-parent populations, could uncover hidden genes for more cooperative crop plants.

Methods
We collected data from greenhouse experiments with the Arabidopsis MAGIC lines in an automated greenhouse at the National Plant Phenomics Centre (University of Aberystwyth, UK).

We present raw data and least-squares mean trait values calculated for each MAGIC line. 

The 'full' dataset includes all 484 lines included in the study.  The 'reduced' dataset excludes some replicates, as explained in the paper.