Root architectural phenes enhancing topsoil foraging are important for phosphorus acquisition. Miguel et al. describe the utility of a novel phene, basal root whorl number (BRWN), that has significant effects on P acquisition in common bean (Phaseolus vulgaris). They define whorls as distinct tiers of basal roots that emerge in a tetrarch fashion along the base of the hypocotyl, and screen wild and domesticated bean taxa as well as a recombinant inbred line populations for BRWN and basal root number. The results indicate that BRWN is associated with increased phosphorus acquisition and that this trait may have value for selection of genotypes with better performance in low-phosphorus soils.
