Ecophysiological differentiation for drought tolerance in Coffea arabica (L.) genotypes

The aim of this study was to define easily recordable and accurate ecophysiological parameters for quick differentiation between genotypes of Arabica coffee (Coffea arabica L.). A nursery trail was set up with two contrasting varieties ('IAPAR 59' and 'Catuaí'). Twenty-one-months-old pot plants were submitted to 0-3-...18 days of drought followed by normal irrigation. The differentiation between stressed and controlled plants, in both varieties, was observed starting from 3rd day for stomatal conductance (gs), plant relative weight, and transpiration (E); from 9th day of drought treatment for leaf water potentials. 'Catuaí' showed greater sensitivity than 'IAPAR 59', and differences in genotype responses were recordable from 9th to 15th day for E and gs and from 9th to 12th day for water potential components. Therefore gs, E or/and water potential component measurements can be used, after nine days of drought in nursery conditions, in classifying Arabica coffee genotypes for drought tolerance, thus allowing screening of great number of plants for association or mapping studies. (Résumé d'auteur