Polyploidy is widely used in plant breeding to increase phenotypic variation and potentially improve stress-related traits; however, its effects in common bean remain poorly characterized. Here, colchicine-induced polyploidy was evaluated in Phaseolus vulgaris cv. Zorzal to determine whether tetraploid lines exhibit coordinated changes in stomatal anatomy, physiology, pigment composition, oxidative balance, and ploidy inheritance. Polyploidy was induced using different colchicine exposure regimes and confirmed by flow cytometry. Stomatal traits, gas-exchange parameters, photosynthetic pigments, oxidative stress markers, antioxidant capacity, and multivariate phenotypic relationships were subsequently analyzed in confirmed tetraploid lines. Colchicine treatments successfully generated tetraploid and mixoploid plants, although induction efficiency was highly variable among replicates. Tetraploid lines showed heterogeneous physiological responses, including increases in the photosynthetic rate and stomatal conductance in some genotypes, but no consistent reduction in stomatal pore area index. Pigment composition and antioxidant-related traits also varied among lines, without a uniform response pattern. Multivariate analyses revealed coordinated but highly divergent phenotypic profiles among tetraploid genotypes. Importantly, the induced tetraploids were not stably transmitted to the C1 generation, with a predominance of diploid progeny among the evaluated offspring. Overall, colchicine-induced polyploidization generated substantial physiological variability among independently derived tetraploid plants of P. vulgaris cv. ‘Zorzal’; however, the predominance of diploid individuals among the evaluated C1 progeny indicates limited transmission of the induced tetraploid state to the subsequent generation.

Blueberries are a fruit with an increasing global demand due to their phytochemical and bioactive compounds content. They are promoted worldwide because of their health benefits. For optimal growth and productivity, blueberry crops need acidic soil pH, specific chilling hours, and an adequate atmospheric temperature. This delicate production equilibrium is under severe threat from climate change, potentially leading to reduced yields and increased cultivation costs unless new cultivars are developed for each edafoclimatic zone. Therefore, considering varietal replacements with more productive cultivars offering higher quality and better adaptability to local conditions is imperative. In this study, we employ polyploidization and in vitro tissue culture to promote variability and lay the foundation for new cultivar development. We report the successful induction of octoploids in three blueberry cultivars, namely 'Biloxi,' 'Legacy,' and 'Duke', through whole-genome duplication. Leaves and microstem explants were exposed to 0.1% colchicine for 24 and 48 hours in in vitro culture. After analyzing the polyploid level of 160 regenerated shoots using DNA flow cytometry, we obtained a total of 18 mutants, consisting of 8 mixoploids and 10 octoploids. The number of chloroplasts in the stomata was analysed by fluorescence microscopy, revealing the duplication of these organelles in the induced octoploid plants. To our knowledge, this represents the first successful induction of octoploids in three blueberry cultivars -'Biloxi,' 'Legacy,' and 'Duke'- achieved by exposing leaves and microstem explants to colchicine in in vitro culture. This technique holds promise as a valuable tool for the development of improved blueberry cultivars.