Host plant resistance and epidemiology of sterility mosaic virus disease in pigeonpea (Cajanus cajan (L.) Millsp.)

Abstract

Field experiments were conducted to identify the resistant sources for Sterility Mosaic Disease (SMD) in pigeonpea at the experimental farm, Department of Pulses,Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University,Coimbatore. Out of 25 genotypes screened under field condition by infector row technique, three entries viz., BDN 2, IPA 8F and MA6 showed resistant reaction to SMD consistently for three years with the mean disease incidence of 8.3, 6.9 and 8.7 % respectively. Seven genotypes viz., BRG1, BRG3, BSMR 736, ICP 7035, ICP 2376, IPA 15F and KPL 44 were categorized as moderately resistant genotypes with the disease incidence ranging from 14.8 - 19.2 %. Six genotypes exhibited moderately susceptible reaction, seven genotypes were susceptible and the remaining two genotypes were highly susceptible to the disease. The susceptible checks viz., CO5 and ICP8863 recorded the SMD incidence of 85.3 and 93.6 % respectively. All the 25 pigeonpea genotypes were also evaluated under glass house for their reaction against SMD by leaf stapler technique. The genotypes, viz., BDN 2, IPA 8F and MA6 also exhibited resistance to SMD under artificial inoculation condition, whereas the susceptible checks viz., CO5 and ICP 8863 recorded 100 % SMD incidence. Wide variations were found between resistant and susceptible pigeonpea genotypes for SMD symptom expressions. The resistant genotypes would be of great value for development of pigeonpea cultivars with SMD resistance. In the present study, results of the experiment on epidemiology of SMD indicated that SMD incidence and mite population were negatively correlated with temperature and positively correlated with relative humidity. The average temperature of 29 - 29.2o C and the RH of 89 - 92.5 % was found to favour the SMD incidence in pigeonpea. The results from this study would be helpful to take timely decision for management of SMD.