Bacterial leaf streak of wheat, caused by Xanthomonas translucens pv. undulosa (Xtu), has become prevalent in Minnesota, South Dakota, and North Dakota over the past eight years. Bacterial leaf streak is currently considered the second most important disease of wheat in Minnesota. Managing bacterial leaf streak is difficult due to the lack of resistant cultivars and other effective tools, especially as fungicides are ineffective against this bacterial pathogen. Over the past eight years we have demonstrated the economic importance of bacterial leaf streak; obtained useful data on the responses of regionally adapted varieties and elite germplasm to Xtu; refined techniques to establish bacterial leaf streak in inoculated field nurseries; and established a regional collaborative nursery to screen elite and released germplasm for response to Xtu.
Our screening efforts have determined that the majority of wheat cultivars and many advanced lines from the regional breeding programs are at least moderately susceptible to bacterial leaf streak and that there is generally less resistance in the regionally available germplasm than is desirable. We plan to continue using screening nurseries to test wheat lines for their response to bacterial leaf streak and to expand the materials we are examining with the intent of identifying additional and/or improved sources of resistance. Previous studies suggest that resistance to bacterial leaf streak is governed by multiple genes and quantitatively inherited.
Information obtained on the response of released varieties and elite germplasm is being utilized by regional wheat breeding programs. Information on the response of released germplasm to bacterial leaf streak has been disseminated to the benefit of regional wheat growers.