1a.Objectives (from AD-416):
The objective of the cooperative research between Louisiana State University and the USDA Agricultural Research Service is to evaluate, identify, and develop sources of resistance to stem rust in wheat.
1b.Approach (from AD-416):
Louisiana State University will identify and obtain sources of stem rust resistance in cooperation with the USDA/ARS Plant Science Research Unit (PSRU), and other collaborating breeding programs. These sources of resistance will be used as parents in the breeding program to introgress stem rust resistance into advanced breeding lines of winter wheat. Top and/or backcrosses to adapted elite lines will be made to develop desirable segregating populations. When available molecular markers for known sources of stem rust resistance will be used to characterize parental lines and in marker assisted transfer and selection of resistance. Segregating populations developed from the introgressions will be inbred and advanced using traditional and/or marker assisted breeding methods when markers are available. Pure lines selected from advance breeding populations will be genotyped using available molecular markers and phenotypes for reaction to stem rust will be obtained in cooperative disease screening experiments conducted in field, greenhouse and/or growth chamber trials. Elite lines having stem rust resistance will be evaluated in regional and uniform yield nurseries, and superior lines will be released as cultivars. Data and germplasm will be shared between ARS, Louisiana State University, and other collaborating scientists.
This research relates to inhouse Objective 1: Identify sources of resistance to foliar fungal pathogens and introgress resistance into adapted wheat.
Stem rust resistant sources, developed by researchers in ARS-Raleigh, were introgressed into high yielding soft wheat lines from the Louisiana State University breeding program. Plants in segregating populations were selected for resistance to yellow rust and powdery mildew in North Carolina. These resistant lines were sent to Kenya for evaluation in the field to Ug99 wheat stem rust. A field-nursery was planted in Baton Rouge, LA for inoculation with an endemic, mildly virulent strain of wheat stem rust. Scores for resistance indicated new form of adult-plant resistance may be present in southern U.S. soft red winter wheats.