Development of in Vitro Screening Technique in Pigeonpea Against Dry Root Rot Disease Caused by Macrophomina Phaseolina (Tassi) Goid

The fungus Macrophomina phaseolina, which causes dry root rot, is a relatively recent danger to the global supply of pigeonpea.Because this pathogen is a polyphagic necrotroph, it remains viable in the soil for several years, making disease management challenging.Using resistant cultivars in an integrated approach is one of the most cost-effective ways to manage dry root rot in pigeonpea.Having a reliable and repeatable screening protocol is pre requisite for resistance breeding programme.Availability of an in vitro screening protocol further reduces the time, efforts, space and expenditure in screening large population against the disease.The present investigation was undertaken to standardise the in vitro screening method for pigeonpea to identify the resistance against M. phaseolina causing dry root rot (DRR) and screening of 27 pigeonpea genotypes and entries against the pathogen.The results were compared with the field screening of all these entries and genotypes against the DRR disease in sick plot.Out of 27 genotypes screened in vitro following paper towel technique, only four genotypes (GRG-811, KRG-33, GRG-152 and ICP-8863) were found moderately resistant.Where as in sick plot, five genotypes were found moderately resistant: GRG-811, KRG-33, GRG-152, ICP-8863, and NAM-2282.The remaining genotypes showed susceptible reaction.Results showed maximum reliability and repeatability of in vitro paper towel method standardised in the study for screening against M. phaseolina.The method shall be used for screening large number of pigeonpea populations in short time, space and cost with high accuracy and repeatability.Further the entries identified moderately resistant to DRR in the present study shall be used for commercial cultivation in disease prone areas and may be used in breeding programmes also.