Résumé
The objective of the study was to evaluate the adaptation of different genotypes of Coffea canephora to the irrigated crop system of the Cerrado from Planalto Central at Brazil, after the period of suspension of the irrigation, through analysis of the water potential and stomatal conductance. Genotypes of Coffea canephora (8V, 8, 30, A1, 14 and 22) that were allocated at Embrapa Cerrados in Planaltina were evaluated. Planting was done in rows per material, using a spacing of 3.7 x 1.0 m in a central pivot irrigation system, with irrigation suspension management during the dry season, for a period of 63 days (June 30 to 31 of August). The evaluations were performed at the end of this period in two times of the day, in fully expanded leaves, of the third or fourth pair, in the middle third of the plagiotropic branches. Leaf water potential (MPa) was measured in the pre-dawn period (Ψam) (3:00 a.m. to 5:00 a.m.) and midday (Ψmd) (12:00 a.m. to 1:00 p.m.) using a Scholander-type pressure chamber. Evaluation of the leaf stomatal conductance (gs-μmol m-2s-1) was performed using a porometer in the abaxial surface of the leaves, in the morning (gs-morning) (08: 30 a.m. to 9:30 a.m.) and at midday (gs- midday) (12:00 a.m. to 1:00 p. m.). Genotype 8 showed a similar behavior to the tolerant clone 14, with higher values of water potential and gs, whereas the 8V genotype maintained an intermediate behavior to clones 14 and 22. Genotypes A1 and 30 showed a behavior similar to or lower than the sensitive clone 22 with lower values of water potential and stomatal conductance. Considering the variables water potential and stomatal conductance, it is concluded that different adaptation strategies to the Cerrado irrigated cultivation system after the irrigation suspension period are observed in the evaluated genotypes. Genotypes 8 and 14 adapt keeping the highest values of water potential and stomatal conductance compared to the other genotypes. Already genotypes A1, 30 and 22 adapt presenting the lowest values of water potential and consequently, lower stomatal conductance. The 8V genotype, in turn, adapts with intermediate behavior when compared to the other genotypes, in relation to the studied variables.