Assessment of resistance to Fusarium wilt disease in sesame (Sesamum indicum L.) germplasm

Inherently low genetic yield potential and susceptibility to biotic and abiotic stresses contribute to low productivity in sesame. Development of stress resistant varieties coupled with high yield is the viable option to raise the genetic yield ceiling. 35 sesame germplasm accessions obtained from diverse agro-climatic regions of India were screened both under natural field and greenhouse conditions to identify disease reaction to the pathogen Fusarium oxysporum spp. sesami. Pathogen was isolated from infected plants and identified fungus inoculum was used to confirm disease reaction. All the accessions displayed some percent infection rate and none could be described as immune. Accessions NSKMS 260, NSKMS-267, NSKMS-261 and TMV-3 were found to be resistant with infection rates of 13.1, 14.6, 15.1 and 15.7% respectively. Accessions RT-54, TMV-4, and NSKMS-115 were found to be moderately resistant. Rest others were found to be moderately susceptible or susceptible or highly susceptible with infection percent ranging from 44.7% to 94.11%. Of all the susceptible ones, TKG-22 and VRISV-1 showed severe infection percent of about 94.1 and 92.3 respectively. Though all the accessions studied were categorized into various classes based on percent disease infection, statistically there is no significant difference in majority of the accessions except NSKMS accessions 260, 261 and 267 and TMV-3. The accessions identified in the present study may be considered in crop improvement programmes involved in developing wilt resistant varieties, however further efforts need to be concentrated on identifying highly resistant genotypes with the inclusion of vast germplasm in screening procedures.