Inheritance of the resistance of Krish sorghum to sugarcane mosaic virus

Abstract

When two plants of Krish sorghum resistant to sugarcane mosaic virus were selfed or used in crosses with susceptible inbred lines, the segregation patterns of the S₁, F₁, bc₁F₁, F₂ and F₃ populations indicated that resistance is controlled by a single gene, with resistance dominant. One of the parents of Krish, i.e. Q12117 introduced from Coimbatore, India, as 'Sorghum halepense 2n = 20', is probably the source of the gene for resistance; tests of Q12117 revealed that three out of 34 seedlings were resistant after being inoculated with the virus four times. The relationship of the Krish gene with the N gene, which controls the mosaic and necrotic reactions in sorghums infected with the Australian Johnson grass strain of sugarcane mosaic virus, has not been definitely established, but it could be either closely linked or an additional allele at the N locus.

The Krish gene for resistance has been transferred by means of a backcrossing program into several commercial sorghum breeding lines without losing its effectiveness against Australian and some overseas strains of sugarcane mosaic virus.