Inheritance of sterility mosaic disease resistance to Bangalore and Patancheru isolates in pigeonpea (Cajanus cajan (L.) Millsp.)

Sterility mosaic disease (SMD), is an important biotic constraint in pigeonpea (Cajanus cajan (L.) Millsp.) in Indiansubcontinent. It is caused by a virus and transmitted by eriophyid mites, Aceria cajani Channabasavanna. A comprehensive studyof variability in the sterility mosaic pathogen revealed the occurrence of five different isolates in India. Amongst them, threedistinct isolates have been characterised, viz., Bangalore, Patancheru and Coimbatore. Studies were conducted at Bangalore andPatancheru to determine the inheritance of resistance to Bangalore and Patancheru isolates of the SMD involving a resistant (ICP7035) and susceptible (TTB 7) genotypes. Observations in parents, F1 indicated dominance of susceptibility over resistance. Thedisease reaction of the individual F2 plant derived F3 families for Patancheru isolate was controlled by two genes with dominanceepistasis and for Bangalore isolate, absence of resistant plants indicate action of two or more genes in controlling resistance toSMD.