Format: ORAL

Rafael Rubio de Casas1, Irene Martn-Brull1, 2, Francisco J. Ocaa-Calahorro1

1 Departamento de Ecología, Universidad de Granada – UGR, Granada, Spain 2 EEAD-CSIC, Zaragoza, Spain.

One of the open questions regarding the relationship between humans and plants is why some taxa are domesticated and become crops while other ecologically and morphologically similar relatives are not. In all likelihood, this is mediated by functional differences between crops and their wild relatives. The identification of this key traits requires accounting for the divergence in ecological and demographic settings between natural populations and crop fields, in which interspecific density is much higher and diversity lower. Traits facilitating growth and survival under these conditions might have thus been relevant for domestication. Using a phylogenetically controlled experiment, we investigated whether domestication might be facilitated by functional traits that increase survival and growth under high density, hyper-competitive conditions. We picked three important annual legume crops, lentil (Lens sp.), grasspea (Lathyrus sp.) and vetch (Vicia sp.) and measured traits that determine competition (lodging; growth rate), resource acquisition (plant height; total aerial and root biomass) and yield (fruit no.). Bayesian models were fitted to these data to quantify the effects of evolutionary divergence between close wild and domestic relatives, as well as between natural and crop (landraces) populations of domesticated taxa. Our results showed important taxonomic differences, likely reflective of different selection pathways. Nevertheless, wild relatives consistently differed from their domesticated congeners in competition and resource acquisition. Never-domesticated taxa consistently produced smaller, slower-growing plants that were more prostrated and allocated less biomass to roots. Conversely, the effect of selection under domestication on vegetative traits was largely negligible, although it appeared to have led to an increase in yield. We conclude that, although domestication processes are always complex and case-dependent, they might indeed favor taxa that are particularly competitive and more effective in resource capture. Subsequent selection under domestication may have targeted reproductive traits (i.e., fruit and seed production).