Screening of Groundnut Varieties, Cultivars, Elite Lines against Sclerotium rolfsii Sacc

Groundnut (Arachis hypogaea L.), is one of the most popular oil seed crops grown throughout the world. During last few years stem/pod rot disease incited by Sclerotium rolfsii Sacc. has attained its serious proportion, thereby inflicting heavy quantitative as well as qualitative losses in groundnut crop. The disease has been reported to cause yield losses of about 48–80 per cent (Mayee and Datar, 1988 and Rakholia et al., 2012). In Maharashtra state, groundnut crop is being grown round the year and the stem/pod rot disease has been found to be quite severe during Kharifas compared to Rabi and Summer grown crop. Under natural epiphytotic conditions (2011–12 and 2012–13), all the 75 groundnut entries exhibited different reactions against S. rolfsii. However, 44 and six test entries were found resistant with mean stem rot incidence in the range of 00.00 to 09.44 and 08.00 to 10.00 per cent, respectively during, 2011–12 and 2012–13. While 25 and 21 test entries were moderately resistant with mean stem rot incidence in the range of 10.38 to 19.35 and 11.55 to 19.75 per cent; 5 and 27 test entries were moderately susceptible with mean stem rot incidence in the range of 22.45 to 29.20 and 20.90 to 29.17 per cent and one and 17 entries were susceptible with mean stem rot incidence in the range of 30.50 to 47.05 and 32.05 to 48.00 per cent, respectively during, 2011–12 and 2012–13. None of the entry was found highly susceptible to the disease during, 2011–12; while, four entries were highly susceptible with mean stem rot incidence in the range of 52.80 to 57.15 per cent during, 2012–13. Under artificial epiphytotics of S. rolfsii (pot culture), all the 75 groundnut entries exhibited different reactions during 2012–13. However, six test entries were resistant with mean stem rot incidence in the range of 6.67 to 10.00 per cent; 20 entries were moderately resistant with mean stem rot incidence in the range of 14.04 to 18.34 per cent; 28 entries were moderately susceptible with mean stem rot incidence in the range of 21.67 to 29.17 per cent; 14 entries were susceptible with mean stem rot incidence in the range of 33.81 to 48.98 per cent; while seven entries were highly susceptible with mean stem rot incidence in the range of 55.00 to 63.33 per cent.