A detached leaf technique for screening beans (Phaseolus vulgaris L.) in vitro against anthracnose (Colletotrichum lindemuthianum)

Se desarrollo un metodo alternativo efectivo para seleccionar frijol blanco por resistencia a la antracnosis (Colletotrichum lindemuthianum) utilizando hojas o foliolos desprendidos. El inoculo se cepillo sobre el enves de las hojas y foliolos desprendidos. Las hojas inoculadas se colocaron, con el lado inoculado hacia arriba, en varias capas de toallas de papel humedo en una bandeja que luego se cubrio con una cubierta transparente o plastica para mantener la alta humedad. Las bandejas se mantuvieron a 22 mas o menos 1 grado centigrado con 9 h de luz diarias durante 6 dias para el desarrollo de sintomas. Con este metodo, se puede evaluar 1 planta varias veces, ya sea por la misma raza o por razas diferentes del patogeno. Esto ultimo es especialmente importante cuando la resistencia a diferentes razas involucra diferentes genes. (RA-CIAT) spa

An effective alternative method of screening white beans for anthracnose (Colletotrichum lindemuthianum) resistance was developed using excised leaves of leaflets. The inoculum was brushed on the underside of the excised leaves and leaflets. The inoculated leaves were placed, inoculated side up, on several layers of wet paper towels in a tray that was then covered with a transparent lid or plastic to maintain high humidity. The trays were kept at 22 plus or minus 1 degree Celsius with 9 h light daily for 6 days for symptom development. With this method 1 plant can be assayed several times either for the same race or for different races of the pathogen. The latter is particularly important when resistance to different races involves different genes. (AS) eng