Factors influencing Agrobacterium tumefaciens-mediated genetic transformation of plants have been widely reported: type and concentration of antibiotic, co-culture period, concentration of bacteria, concentration of acetosyringone, and of course, the type and age of the explants, as well as temperature conditions. However, it is not yet understood how these factors interact and how they affect the efficiency of the final transformation. The aim of this work was to evaluate the interaction of the three main factors affecting the transformation of chrysanthemum (Dendranthema grandiflora) var. Micromargara. A 2 3 factorial design was used with central points, in which three concentrations of A. tumefaciens (1.0, 1.5. and 2.0 of D.O. 600 ), three concentrations of acetosyringone (50 μM, 75 μM and 100 μM), and three co-culture periods (1, 2 and 3 days) were evaluated. The transformation was verified by GUS staining and by means of RT-PCR amplification and sequencing of fragment of the genes uidA, aph3 II and act-cr. The results show that, among the factors evaluated, only the concentration of A. tumefaciens presented a statistically significant effect (p< 0.05) on transformation efficiency, without interaction with the factors of acetosyringone concentration and co-culture period. It is concluded therefore that an A. tumefaciens concentration of D.O 600 : 2.0 is determinant for greater transformation efficiency in chrysanthemum var. Micromargara.

Podopterus mexicanus Humb. & Bonpl. Polygonaceae. "Rompe capa". Árboles o arbustos de 1.5-6.0 m de altura, ramas con espina terminal, braquiblastos, hojas fasciculadas, flores blancas a verdosas en fascículos, y frutos cubiertos por el perianto externo que forma alas delgadas y largamente decurrentes hacia el pedicelo. Crece en bosques tropicales caducifolios y bosques espinosos, sobre suelo rocoso negro derivado de rocas ígneas. En elevaciones de 550-760 m. Florece de abril a mayo y fructifica de junio a septiembre.