Variability and nutritional balance among genotypes of Coffea canephora (Rubiaceae) in drought versus adequate water supply

We examined the effect of water availability on the nutritional balance of 15 genotypes of the clonal cultivar “Conilon BRS Ouro Preto” of Coffea canephora grown in two contrasting environments in terms of water availability. Biomass production and nutritional balance parameters, based on the deviance from the standard ratio among nutrients for the species, were estimated after 170 days of cultivation in these contrasting environments. The variability of responses among genotypes indicated a favorable for identifying diversity among these genotypes and for selection aiming to explore their nutritional parameters, especially for the concentration of phosphorus and magnesium in green tissues. Cultivation in the environments with low water supply caused losses up to 29% in the biomass production of the young plants (with most severe losses observed for the aerial part); the magnitude of these losses varied among genotypes. Genotypes 125 and 155 accumulated significantly higher amounts of biomass when compared to the others, regardless of the water supply. Overall, the nutritional indexes of the tested genotypes showed greater metabolic inflexibility towards water stress than what is reported for other cultivars of Robusta coffee.