Sources of resistance to downy mildew in wild and weedy sorghums uri icon

abstract

  • Sorghum downy mildew (SDM), caused by Peronosclerospora sorghi Weston and Uppal (Shaw), is a serious disease of sorghum (Sorghum bicolor (U.) Moench) and maize (Zea mays U.). The wild relatives of sorghum, both cross compatible and cross incompatible with S. Bicolor, could provide alternate sources of resistance genes for the long-term control of SDM. The objective of this study was to assess the downy mildew reaction of several taxa of wild and weedy sorghums. One hundred three wild and weedy sorghums, and six cultivated types belonging to five sections, representing 17 species, originating from Asia, Australia, Africa, and the USA, were greenhouse tested for downy mildew resistance during the rainy seasons of 1998 and 1999 at ICRISAT. Patancheru, India. Forty-five accessions comprising 15 species from four sections, parasorghum, heterosorghum (S.Laxiflorum Bailey.), chaetosorghum (S. macrospermum Garber), and stiposorghum (S. Angustum S. T. Blake, S. Ecarinatum Lazarides, S. Extans Lazarides, S. Intrans F. Muell. Ex Benth., S. Interjectum Lazarides, S. Stipoideum (Ewart & Jean White) C. Gardener & C. E. Hubb.), including all accessions from Australia, exhibited immunity to downy mildew. Cultivated types and wild races of section Sorghum showed the greatest susceptibility (mean downy mildew infection of 62 and 46%, respectively), while accessions of S. Halepense (U.) Pers. Were comparatively less susceptible (36% mean downy mildew infection). Potential new sources of resistance genes from wild and weedy sorghums were identified that could be used to develop resistant cultivars to control downy mildew

publication date

  • 2002
  • 2002