The inheritance of the red leaf reaction of grain sorghum to sugarcane mosaic virus infection

Abstract

The hypothesis that the necrotic red leaf and red stripe reactions of grain sorghum to sugar-cane mosaic virus – Johnson grass strain infection are independently inherited was tested. Five F₁ and 15 F₂ populations and one bc₁F₁ population were grown under both high (26.6–23.8°C) and low (15.5°) temperature regimes following manual inoculation with the virus. The results were consistent with the hypothesis that the presence of a homozygous recessive allele, termed rlf, conditions the expression of the necrotic red leaf reaction following exposure of plants to low temperatures. Plants express only mosaic symptoms in the presence of the dominant allele RLF and the absence of the N gene. The previously reported N gene and the rlf gene were shown to be independently inherited.