Inheritance of Resistance to Sterility Mosaic Virus in Pigeonpea

To study the inheritance of resistance to sterility mosaic in pigeonpea, [Cajanus cajan (L). Millsp]., five resistant (Pant A3, ICP 3783, ICP 6997, ICP 7035 and ICP 7119) and three susceptible (Pant A2, UPAS 120 and T 21) lines were crossed in all possible combinations. The F₁, F₂, BC₁ and BC₂ generations were planted in the field under artificial inoculation using ‘PSMV sick-plot’ and ‘leaf-stapling’ procedures. Resistance to sterility mosaic virus appeared to be governed by four independent non-allelic genes. The presence of atleast one dominant and one recessive gene was necessary for resistance. The symbols, Sv₁, Sv₂, sv₂ and sv₄ were assigned to the four resistance genes. Sv₁ and Sv₂ showed duplicate dominant epistasis whereas SV₃ andsv₄ shows duplicate recessive epistasis for resistance. Resistant lines, TCP 3783’, TCP 7035’ and TCP 7119’ had one dominant and two recessive genes (Sv₁, SV₃ and sv₄) whereas TCP 6997’ had one dominant and one recessive gene (Sv₁, SV₃) and Pant A3 had another dominant and one recessive gene (Sv₂, SV₃) for resistance. The susceptible lines, involved in the present study, did not have any gene for resistance to PSMV in pigeonpea.