Method for early screening of fusarium wilt in pigeonpea [cajanns cajan (l.) millsp]

Pigeonpea [Cajanus cajan (L.) Millsp] is one of the important grain legume and is a rich source of protein. Though India ranks first in production, the productivity of pigeonpea is very low because of its vulnerability to a number of biotic stresses. Among these stresses the Fusarium wilt caused by Fusarium udum (Butler) is the most important limiting factor and is prevalent in all pigeonpea growing areas. Three methods namely root tip inoculation, piercing method and disease sick plot method were attempted. The first two methods were carried out at green house, Institute of biotechnology (IBT), Professor Jaya Shankar Telangana State Agricultural University (PJTSAU), Hyderabad, during Kharif 2013, and the third method was carried out at (Agriculture research station) ARS, Tandur during Kharif 2013. In all the three methods, the disease was observed and the levels of disease resistance/susceptibility among the RILs were comparable except for the difference in the total number of days taken for the complete expression of disease symptoms. In case of disease sick plot method, it took 150-180 days whereas in case of root tip inoculation a maximum of 60 days were sufficient for complete expression of disease symptoms and it took around 90-120 days in case of piercing method. Hence root tip inoculation method is ideal, as it takes less time for expression of the disease and hence it is possible to take up multiple screenings within a single season. This would also aid in effective and quicker identification of resistant and susceptible RILs for further crop improvement applications without waiting for next season. This is the first report, indicating that mechanical inoculation of Fusarium udum (Butler) by root tip inoculation is more effective method than other two methods for screening this disease.