This study aimed to establish a strategy for drought-tolerant selection in Arabica coffee genotypes in Brazil, combining field trials under natural conditions with controlled growth condition experiments. A group of genotypes was evaluated in the greenhouse using 28 morphological, anatomical, and physiological traits. In addition, the productivity of genotypes was evaluated in the field. Under water deficit in the greenhouse, 13 studied traits showed significant genetic variance. For these traits, the heritability coefficients estimated based on the progeny mean ranged from 65 to 92%. A selection index combined with predicted means was applied at these traits to select four progenies for drought tolerance under greenhouse conditions. Under field conditions, the selection applied to genetic values that favored positive genetic gains in four progenies, indicating the potential use of these cultivars for breeding advanced generations. The selection results of coffee plants under greenhouse conditions matched the selection results in the field in a water-deficit region by 50% based on productivity; thus, two genotypes (H419-3-3-7-16-11 and H516-2-1-1-7-2) were identified that have both the productivity and morpho-anatomical traits that confer greater drought tolerance. Finally, we discussed possible strategies for the development of drought-tolerant cultivars.

The adaptive potential of plants is commonly used as an indicator of genotypes with higher breeding program potential. However, the complexity and interaction of plant metabolic parameters pose a challenge to selection strategies. In this context, this study aimed to explore phenotypic plasticity within the germplasm of Hybrid Timor coffee. Additionally, we assessed the utility of the multivariate phenotypic plasticity index (MVPi) as a promising tool to predict genotype performance across diverse climatic conditions. To achieve this, we evaluated the performance of seven accessions from the Hybrid Timor germplasm in comparison to the Rubi and IPR 100 cultivars, known for their susceptibility and resistance to drought, respectively. The experiment took place in a greenhouse under two conditions: one with normal soil moisture levels near maximum capacity, and the other with a water deficit scenario involving a period of no irrigation followed by rehydration. Data on physiological and biochemical factors were collected at three stages: before applying the water deficit, during its imposition, and after rehydration. Growth data were obtained by the difference between the beginning and end of the experimental period Furthermore, field evaluations of the productivity of the same genotypes were carried out over two consecutive seasons. Based on physiological and biochemical assessments, the MVPi was computed, employing Euclidean distance between principal component multivariate analysis scores. Subsequently, this index was correlated with growth and productivity data through linear regressions. Our findings reveal that the plastic genotypes that are capable of significantly altering physiological and biochemical parameters in response to environmental stimuli exhibited reduced biomass loss in both aerial and root parts. As a result, this positively influenced their productivity. Enhanced plasticity was particularly prominent in accessions from the MG Germplasm Collection: MG 311—Hybrid Timor UFV 428-02, MG 270—Hybrid Timor UFV 377-21, and MG 279—Hybrid Timor UFV 376-31, alongside the Rubi MG 1192 cultivar. The MVPi emerged as a valuable instrument to assess genotype adaptability and predict their performance under varying climatic scenarios.

Climate change threatens the survival of commercial crops due to their narrow genetic base. One of the alternatives is the identification of plants with potential for abiotic stress tolerance. This study aimed to verify the physiological and anatomical adaptations to the drought period and the impacts on the yield of ‘Híbrido de Timor’ coffee tree accessions. The experimental design was randomized blocks, in a 7 x 2 factorial arrangement, being seven genotypes (UFV 377-21, UFV 377-21, UFV 442-42, BE 5 Wush-Wush x UFV 366-08, UFV 428-02, UFV 376-31 and UFV 427-55) and two seasonal periods (dry and rainy), with two replications. The stomatal conductance; predawn water potential; levels of hydrogen peroxide and malondialdehyde; activity of the enzymes catalase, superoxide dismutase and ascorbate oxidase; ascorbate content; cuticle thickness of the adaxial surface and leaf lamina; stomatal density; ratio between polar and equatorial diameter; phloem area; area, diameter and frequency of xylem vessels; relative hydraulic conductivity; vulnerability index; and yield were evaluated. The results showed acclimatization of the accessions to the dry period, with some of them maintaining higher water potential values in the predawn; induction of the antioxidant system with the increase in the activity of the superoxide dismutase enzyme and ascorbate levels; increase in the cuticle and leaf lamina thickness; and a higher ratio between polar and equatorial diameters. Most of the evaluated accessions showed a good productive performance, especially the ‘UFV 377-21’, ‘UFV 442-42’ and ‘UFV 376-31’, with adaptations to the dry period and yield potential.

Plants exhibit the capacity for adaptation through their metabolic processes to various changes in environmental conditions. Investigating these adaptations in current and future climatic scenarios is of great importance for ensuring productive agricultural crops. This adaptative potential is commonly employed as an indicator of genotypes with higher potential in breeding programs. However, the complexity and interaction of plant metabolic parameters pose a challenge to selection strategies. In this context, the aim of this study was to explore phenotypic plasticity within the germplasm of Hybrid Timor coffee. Additionally, we assessed the utility of the Phenotypic Plasticity Index (MVPi) as a promising tool to predict genotype performance across diverse climatic conditions. To achieve this, we evaluated the performance of seven accessions from the Hybrid Timor germplasm in comparison to the Rubi and IPR 100 cultivars, known for their susceptibility and resistance to drought, respectively. The experiment was conducted at greenhouse conditions, with two treatments: a control scenario, maintaining soil moisture near its maximum water-holding capacity, and a water deficit scenario involving irrigation cessation followed by rehydration. Data encompassing physiological, biochemical, and growth aspects were collected during three distinct stages: pre-application of water deficit, its imposition, and subsequent rehydration. Furthermore, field evaluations of the productivity of the same genotypes were carried out over two consecutive seasons. Based on physiological and biochemical assessments, the MVPi was computed, employing Euclidean distance between principal component multivariate analysis scores. Subsequently, this index was correlated with growth and productivity data through linear regressions. Our findings reveal that the more plastic genotypes, capable of significantly altering physiological and biochemical parameters in response to environmental stimuli, exhibited reduced biomass loss in both aerial and root parts, consequently positively influencing their productivity. Enhanced plasticity was particularly prominent in accessions from the MG Germplasm Collection: MG 311 - Hybrid Timor UFV 428-02, MG 270 - Hybrid Timor UFV 377-21, and MG 279 - Hybrid Timor UFV 376-31, alongside the Rubi MG 1192 cultivar. The MVPi emerged as a valuable instrument to assess genotype adaptability and predict their performance under varying climatic scenarios.

The development of more drought-tolerant cultivars is essential for the maintenance of global agricultural production. This study aimed to perform an early selection of drought-tolerant Coffea arabica genotypes by evaluating their functional divergence using morphological, anatomical and physiological analyses. Seedlings of 14 genotypes were subjected to the drought stress imposed by irrigation for 18 days. Growth and anatomical parameters, leaf water potential and gas exchanges were measured. Under irrigated conditions and prolonged drought (18 days), the divergence among the genotypes was determined mainly by morphological traits, such as leaf area, stem diameter and, consequently, shoot dry mass. Under moderate drought (14 days), parameters such as water potential, cuticle thickness, stomatal density, number of xylem vessels and water-use efficiency were important for the divergence of the group with the highest ability to maintain its water status. The genotypes 1, 2, 4, 11 and 12 have characteristics that contributed to the maintenance of water status, such as greater cuticle thickness, stomatal density, smaller number of xylem vessels and phloem thickness, bigger root length and greater water-use efficiency. The functional divergence combining morphological, anatomical and physiological analyses in response to the moderate drought indicated the early selection of the genotypes 1, 2,4, 11 and 12 as more drought tolerant during the seedling stage.