Chiang Mai Journal of Science

     Agrobacterium-mediated transformation is a widely used method for modifying plant genomes, but it can lead to unintended effects on plant morphology and development. In this study, we examined the impact of this transformation technique on Cosmos sulphureus, focusing on the T3 generation of transgenic plants. Using anti biotic selection and molecular verificati on, the presence of the nptII gene was confirmed in 78.72% of the transformed population. Inheritance analysis showed deviations from expected Mendelian segregation ratios, possibly due to maternal effects. Phenotypic evaluation revealed significant morphological changes in transgenic lines, including reduced plant height and altered branching patterns. However, some floral traits, such as petal width and disc diameter, remained unaffected. To investigate the underlying causes of these changes, we analyzed the YABBY gene, known to influence organ development and leaf morphology. Molecular analysis of the YABBY gene segment showed atypical amplification patterns, suggesting potential alterations caused by random gene insertions. These findings highlight the unintended consequences of genetic transformation and underscore the need for comprehensive molecular and phenotypic assessments in plant genetic engineering.