Evaluation of groundnut genotypes for resistance to Sclerotium rolfsii under artificial field inoculated conditions

Stem and pod rot caused by Sclerotium rolfsii is the major constraint to groundnut production in manygroundnut growing regions of the world. Paucity of suitable field screening methods to identify sclerotiumresistant genotypes hinders the progress of resistance breeding. A sick plot with high inoculum load ofSclerotium rolfsii, was established. A total of 165 sergeants derived from TAG 24 (adopted but susceptiblevariety) . R 9227 (stem rot resistant variety) were screened for resistance to stem and pod rot. The Fs and F6generations were grown in the sick plot to confirm their reaction to stem and pod rot. Among differentparameters, variation was highly heritable for yield per plant, disease incidence parameters potential forselection under disease epidemics. Strong negative association between disease incidence and yield perplant revealed the importance of disease incidence in determination of yield per plant under epiphytoticconditions. The higher number of superior segregants observed for p0d weight per plant (26), oil content(21), test weight ( 19) and shelling percentage (8) and disease at harvest (6) were compared to both theparents. None of the genotypes showed complete resistance. It is unlikely that highly resistant genotypes toneurotropic pathogen like Sclerotium rolfsii would be identified. However information obtained ongenotypic variance, heritability, genetic advances and association of disease with yield and lines selectedwith considerable sclerotium resistance with good yield attributing characters (6) can be utilized in futurebreeding programs

S Pujer, P V Kenchangoudar, M V C Gowda, B N Motagi, 'Evaluation of groundnut genotypes for resistance to Sclerotium rolfsii under artificial field inoculated conditions', p.18, 2016