Identification of resistance sources against root rot, Macrophomina phaseolina in castor genotypes

摘要

Castor (Ricinus communis L.j root rot caused by Macrophomina phaseolina is one of the most destructive disease and causes severe losses in yield. Therefore, the present investigation was undertaken to screen different genotypes/varieties for their resistance to root rot which can be used in cultivar improvement. Thirty-two genotypes/varieties of castor were evaluated for locating new and better sources of resistance against root rot under sick plot conditions. Out of that, four genotypes JI-357 (4.95%), JHB-1022 (6.66%), JHB-1013 (17.62%) and SHB-982 (17.62%) regarded as resistant. While seventeen genotypes found moderately resistance with 32.72% to 21.11% disease incidence. None of the entries were completely free from root rot infection and all the genotypes were more or less affected by the disease. The genotypes identified as resistant are of great value and may be exploited in the breeding program for developing high yielding resistant varieties.