Growth and biomass-allocation responses of arabica coffee young plants subjected to the interactive effects of root deformation and light availability

The root deformation at the time of pricking out is a well-recognized problem that interferes with coffee crop productivity. Considering that coffee cultivation under shade of agroforestry systems in the tropics is an important way of reconciling crop production and environmental services, we conducted an experiment to assess the effects of root deformation and light availability on growth and biomass allocation of Coffea arabica young plants. Seedlings of cultivar Catucaí Amarelo 24–137, without and with root deformation, were cultivated in pots for 110 days under daily light integral (DLI) of 20, 10, and 1 mol photons m⁻² day⁻¹ (corresponding to about 60%, 30% and 3% of full sunlight). Regardless of the light treatments, root deformations had unfavorable effects on plant growth. The relative growth rate (RGR) and net assimilation rate (NAR) were severely affected by the lowest light availability (3% of full sunlight). Plants cultivated above 30% of full sunlight allocated more biomass to the roots, and plants cultivated under 3% of full sunlight allocated more biomass to the stems and leaves. The synergistic effect of light and root deformation negatively impacted RGR and the ratio between height and stem diameter (H/D). We demonstrated that errors in the pricking out process interfere with the biomass allocation, affecting the quality and growth performance of C. arabica seedlings at contrasting light availabilities.