Cafeeiros potencialmente tolerantes ao déficit hídrico na fase de formação da lavoura

Abstract

The aim of this study was to select coffee trees that are potentially tolerant to water deficit during the crop formation phase. A group of 17 genotypes (16 cultivars and 1 progeny) was evaluated under natural conditions at the Epamig Oeste Experimental Field, Patrocínio - MG, using 24 physiological, anatomical and growth characteristics, as well as differential gene expression of aquaporins and candidate drought-related genes (Gs). Two experiments were carried out with the arabica coffee genotypes, one under rainfed conditions and the other under drip irrigation during the dry season. Both experiments were in a randomized block design with 17 genotypes, each with four replications. The experimental plot consisted of eight plants, with the three central plants being the useful plot for the evaluations. The evaluations were carried out five months after the seedlings were planted in the field. The experimental period was 75 days, with three evaluations in the field. After the agronomic and physiological characterization of the 17 genotypes, nine genotypes were pre-selected for anatomical characterization, and then five genotypes were pre-selected to evaluate differential gene expression using qPCR. Multivariate analyses were carried out to distinguish between the genotypes and the relevant variables. There was a difference between the performance of the genotypes evaluated. In short, the genotypes with the greatest potential for tolerance to water deficit were MGS Ametista, MGS Aranãs, MGS Paraíso 2, IAC 125 RN, IAC Catuaí SH3 and Acauã Novo, which showed greater maintenance of water potential associated with good water efficiency, positively impacting gas exchange and initial growth during water deficit in field conditions. The IAC Catuaí SH3 and MGS Paraíso 2 genotypes showed efficient molecular responses in water transport and water potential conservation during the dry season. The PIP 1:3 genes, CaGolS3 and CaDHN1, showed greater relative gene expression under water deficit in Coffea arabica genotypes.