Obtenção de plantas poliplóides de Stylosanthes guianensis via cultura de calos

Abstract

This study aimed to induce polyploidy in Stylosanthes guianensis through the application of colchicine as an antimitotic agent in calli cultured in vitro. S. guianensis is a leguminous species of great agricultural relevance, widely used in grazing systems and for the recovery of degraded soils. It is notable for its adaptability to acidic and nutrient-poor soils, as well as for its efficient biological nitrogen fixation, which improves soil fertility and benefits associated plant species. In the experiment, calli were exposed to different concentrations of colchicine (0.01% and 0.05%) for 6 and 12 hours. All concentrations proved effective in producing polyploid individuals; however, the concentration of 0.01% applied for 12 hours yielded the highest number of polyploids, resulting in successful DNA duplication (5.8 picograms) and an increased chromosome number (2n = 4x = 40). Morphological analyses of leaves and stomata showed significant differences between diploid and tetraploid plants, with increased leaf and stomatal dimensions in the polyploid individuals, indicating phenotypic changes associated with chromosome duplication. The induction of polyploidy in S. guianensis showed potential for obtaining plants with greater biomass, contributing to the development of more nutritious cultivars. The results provide valuable insights for genetic improvement programs in tropical forage species and highlight the importance of plant biotechnology in sustainable agriculture.