Abstract
Management of black scurf disease through determining levels of susceptibility in 12 germplasm lines and varieties of potato was investigated by using Rhizoctonia solani AG 3 isolate SL-41, previously characterized according to anastomosis group and pathogenicity against eight disease producing symptoms (parameters) of black scurf disease viz., eyes germination, number of sprouts, sprouts killed, stem girdling, stem canker, stolon canker, black scurf incidence and severity. Overall, statistically non-significant differences between inoculated and non-inoculated treatments were found in varieties SH-5, SH-20 and germplasm ,line CIP-9605 except black scurf incidence (37.33%) in var. SH-20, black scurf severity of 1.86 in var. SH-5 on rating scale of 0-5 and number of sprouts in line CIP-9605, where significant differences were found between inoculated and non inoculated treatments. Varieties SH-5, SH-20 and line CIP- 9605 were found resistant to the disease causing fungus when compared with the remaining lines and varieties. Faisalabad white was found to be the most susceptible variety as statistically, significant differences for eyes germination, number of sprouts, sprouts killed, black scurf incidence and severity were found. As it is susceptible to black scurf disease pathogen, therefore, it could not be grown as a resistant variety against R. solani particularly in agro-ecological zone 2 comprising of Sahiwal, Pakpatan, Okara, Sialkot, Narowal, Jhang and Faisalabad districts, where the disease is already a problem.
