Abstract
In this study, 78 accessions from Chad, Central Africa and 20 photoperiod insensitive accessions from Uganda, East Africa were evaluated for downy mildew resistance in Ocotlan, Mexico in 2004 and 2005. Ninety-four of these accessions were also evaluated at two locations in Wharton County, Texas, USA, in 2005. Accessions were planted in a randomized complete block design with each sorghum accession replicated three times. Disease incidence was determined from natural infection. Disease incidence varied between locations, with the highest mean disease incidence observed for the Mexican evaluation. Germplasm from Chad also showed a higher mean disease incidence than germplasm from Uganda. Several sources of downy mildew resistance were identified. Three accessions PI282860, PI282864, and PI563505 from Chad were shown to possess high levels of downy mildew resistance in Mexico and Texas, whereas PI282843, PI282877, PI549196, and PI563438 also from Chad exhibited high levels of resistance to the disease in Texas. Accessions PI297210, PI576386 and PI576395 from Uganda also showed downy mildew resistance in Mexico and Texas. These sorghum accessions from Chad and Uganda can be utilized in breeding for downy mildew resistance in Mexico and Texas.
Zusammenfassung
In dieser Untersuchung wurden 78 Sorghum-Akzessionen aus dem Tschad und 20 photoperiodisch neutral reagierende Sorghum-Akzessionen aus Uganda hinsichtlich ihrer Resistenz gegenüber dem Falschen Mehltau in den Jahren 2004 und 2005 in Ocotlan, Mexiko, überprüft. Vierundneunzig dieser Akzessionen wurden 2005 auch in Wharton County, Texas, getestet. Die Akzessionen wurden in einer vollständig randomisierten Blockanlage mit drei Wiederholungen pro Akzession gepflanzt. Die Befallshäufigkeit wurde nach natürlicher Infektion bestimmt. Die Befallshäufigkeit variierte zwischen den Standorten, wobei die höchsten mittleren Werte in Mexiko beobachtet wurden. Tschadische Herkünfte wiesen höhere Befallshäufigkeiten auf als ugandische. Mehrere Resistenzquellen gegen den Falschen Mehltau wurden identifiziert. Die drei tschadischen Akzessionen PI282860, PI282864 und PI563505 zeigten hohe Grade von Mehltauresistenz in Mexiko und Texas, während die ebenfalls aus dem Tschad stammenden Akzessionen PI282843, PI282877, PI549196 und PI563438 hohe Resistenzgrade nur in Texas aufwiesen. Die ugandischen Akzessionen PI297210, PI576386 und PI576395 waren gegenüber dem Falschen Mehltau in Mexiko und Texas resistent. Diese Sorghum-Akzessionen aus Uganda und dem Tschad können daher zur Züchtung mehltauresistenter Sorghum-Sorten sowohl in Mexico als auch in Texas verwendet werden.
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Prom, L.K., Montes-Garcia, N., Erpelding, J.E. et al. Response of sorghum accessions from Chad and Uganda to natural infection by the downy mildew pathogen, Peronosclerospora sorghi in Mexico and the USA. J Plant Dis Prot 117, 2–8 (2010). https://doi.org/10.1007/BF03356326
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DOI: https://doi.org/10.1007/BF03356326