Estudio del control del hongo colletotrichum sp. en semillas de chocho (lupinus mutabilis s.) con radiaciones ionizantes generadas por un acelerador de electrones.

Abstract

The fungus Colletotrichum sp. causes anthracnose in sweet lupin (Lupinus mutabilis Sweet). The use of ionizing radiations generated by an electron accelerator was evaluated for the control of this pathogen in lupin seeds. The fungus was isolated from pods that showed symptoms of the disease, and pure strains were obtained through a monosporic culture. The pathogen was inoculated in Petri dishes with Potato Dextrose Agar (PDA), and the plates were irradiated with radiation doses of 1.2, 1.5, 2.0, and 4.0 kGy in an ELU-6U linear electron accelerator beam. The surviving colony-forming units were counted to build a mortality curve. The decimal reduction (D10) was found to be 0.7 kGy. Next, germination and vigor were evaluated 12 days after sowing of seeds irradiated with doses of 1.2; 1.5; 2.0; 4.0; 8.0; and 16.0 kGy. Since a dose higher than 2.0 kGy was required to completely control the pathogen, and a value lower than 4.0 kGy was necessary for an adequate survival of the plants, 2.5 kGy was selected as the best dose (BD). Subsequently, the initial development of the plants and the incidence of the pathogen at 30 days after sowing were analyzed, with seeds irradiated at the best dose. Although the resulting plants were shorter (12.40 cm for BD and 24.61 cm for the control), the germination and vigor rates were high (96.0% and 92.8%, respectively), and the number of infected plants was zero.