Improving evaluation of potato resistance to Rhizoctonia solani infection by optimizing inoculum-based method combined with toxin-based assay

Rhizoctonia solani causes stem canker and significantly impacts potato production. Conventional assay to evaluate resistance using R. inoculum is time consuming. To establish an effective fast assay, 20 cultivars/lines were examined both AG2-1 as its derived toxin (RS toxin). In field trials of 2009 2010, wheat-bran-mediated was incorporated at either 0, 2, 3, 4 or 5 g per seed piece in the soil before sowing furrow. Stem evaluated sixty-five days after planting. Inoculation well distinguished cultivars/lines. For a quick screening, toxin-based method established by treating seedlings with RS AG2-1. prepared heating culture. Potato obtained through tissue culture grown Murashige Skoog medium. Seedlings stage 12 cm height transferred into agar amended incubated for eight days. The level inhibition caused positively correlated concentration. By evaluating various cultivars/liens that have different sensitivities toxin, from 33% 100% on stems sections 32% 148% seedlings. evaluation highly data pathogen (r = 0.731, P < 0.01). wheat bran-mediated 3 evaluations. improved efficiency disease evaluation. Both assays showed none completely resistant However, cultivar ‘Desiree’ had lowest disease, whereas ‘Atlantic’, ‘Favorita’, ‘Shepody’ most susceptible cultivars.