Resumen en inglés

Stevia (Stevia rebaudiana Bert.) is a natural sweetener with low-calorie steviol glycosides (GS) and medicinal properties that provide great health benefits. The University of Córdoba needs to characterize the plant genetic resources of S. rebaudiana to identify divergent genotypes and improve the species. The study was carried out in the year 2022 in the experimental area of the University of Córdoba, and for this purpose a randomized complete block design (DBCA) was established, with 87 treatments and 3 repetitions, evaluating 25 morphoagronomic characters based on the descriptor of UPOV. Principal component analysis was used to identify discriminant characters and analysis of genetic divergence using the UPGMA method based on Gower's distance. In addition, the gas exchange efficiency was evaluated using an open-flow portable infrared gas analyzer. The results demonstrated that the clones exhibited a wide range of genetic variability for the characteristics: initial flowering stage and leaf shape. Principal component analysis explained 69.57% of the variation with eight components and identified the variables with the most variation: CP1 with 19.65% in plant height, CP2 with 12.58% in the initial flowering stage, CP3 with 10.58% in flower size, CP4 with 7.04% in plant type, CP5 with 5.71% in the presence of anthocyanin in the stem, CP6 with 4.84% in number of nodes, CP7 with 4 80% in resistance to the southern blight disease and CP8 with 4.37% in incision of the leaf margin. The quantitative descriptors that most contributed to genetic diversity were vegetative propagation capacity, number of nodes and stem thickness; these traits were more efficient to explain the dissimilarity between genotypes. Through the cluster analysis, 4 groups were formed, of which they had 3, 1, 66 and 17 genotypes; where clone L052 was identified as a genotype apart from the others, because it does not present pubescence on the leaf, late flowering stage, pale green leaf color and a favorable trait of number of primary branches. The L020 and L102 genotypes of the first group presented desirable characteristics for biomass production, these being the most divergent and with favorable agronomic attributes. In addition, clone L020 has characteristics such as high efficiency in water use and high net photosynthesis, reflected in a greater 14 production of leaf area. The clones of group 3 were the earliest to flowering, short cycle and the lowest rates of dry yield, with clone L082 presenting the earliest flowering, which makes this group agronomically undesirable; while the last group has the genotypes with the smallest thickness of the stem and intermediate flowering represented by clone L057. These results allow the selection of clones L020 and L102 for their evaluation in the producing areas of the Caribbean region, through Agronomic Evaluation Tests and/or to be used as parents for the genetic improvement program.