Identification of QL-3 Sorghum, a Source of Resistance to Peronosclerospora sorghi. R. J. Williams, International Crops Research Institute for the Semi-Arid Tropics, Patancheru P.O., Andhra Pradesh 502 324, India. S. R. S. Dange, L. K. Mughogho, and K. N. Rao, International Crops Research Institute for the Semi-Arid Tropics, Patancheru P.O., Andhra Pradesh 502 324, India. Plant Dis. 66:807-809. Accepted for publication 13 July 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-807.

In 3 yr of testing in India, Botswana, Venezuela, and the USA, a selection of the Australian sorghum (Sorghum bicolor) line QL-3 has remained free from symptoms of sorghum downy mildew when exposed to oospores and conidia of Peronosclerospora sorghi in field trials. In addition, the QL-3 resistance has remained effective when inoculated with conidia of the fungus by four techniques that resulted in the breakdown of resistance of other field-resistant cultivars. QL-3 was developed first in Australia for resistance to the sugarcane mosaic virus, but this resistance to the virus has also been effective in Asia, Europe, and the Americas. Thus the QL-3 selection represents a valuable source of combined resistance to two important pathogens of sorghum.

Keyword(s): multilocational testing.