Glyphosate is a broad-spectrum herbicide used for the control of weeds in glyphosate-resistant crops. Glyphosate inhibits 5-enolpyruvyl shikimate 3-phosphate synthase, a key enzyme in the synthesis of aromatic amino acids in plants, fungi, and bacteria. Studies with glyphosate-resistant wheat have shown that glyphosate provided both preventive and curative activities against Puccinia striiformis f. sp. tritici and Puccinia triticina, which cause stripe and leaf rusts, respectively, in wheat. Growth-chamber studies demonstrated wheat rust control at multiple plant growth stages with a glyphosate spray dose typically recommended for weed control. Rust control was absent in formulation controls without glyphosate, dependent on systemic glyphosate concentrations in leaf tissues, and not mediated through induction of four common systemic acquired resistance genes. A field test with endemic stripe rust inoculum confirmed the activities of glyphosate pre-and postinfestation. Preliminary greenhouse studies also demonstrated that application of glyphosate in glyphosate-resistant soybeans suppressed Asian soybean rust, caused by Phakopsora pachyrhizi.Phakopsora pachyrhizi ͉ Puccinia striiformis f. sp. tritici ͉ Puccinia triticina ͉ disease control

The WSMV-resistant germplasm, KS93WGRC27, contains a translocation from Thinopyrum intermedium Development of wheat (Triticum aestivum L.) cultivars resistant (Host) Barkworth and Dewey chromosomal arm 4J s to Wheat streak mosaic virus (WSMV) that remain productive in the absence of the disease would benefit wheat growers. A wheat that carries the resistance gene Wsm1 (Lay et al., 1971; germplasm (KS93WGRC27) carrying a Thinopyrum intermedium Friebe et al., 1991; Gill et al., 1995; Chen et al., 1998). (Host) Barkworth and Dewey chromosome 4J s translocation confer-The line is a BC 3 F 2 -derived line from the backcross of ring WSMV resistance was used to develop spring wheat populations the high yielding hard red winter wheat cultivar Karl segregating for WSMV resistance. Four populations, consisting of a with CItr 17884 (Gill et al., 1995). CItr 17884 is a 'Centotal of 22 translocation-positive (WSMV-resistant), 36 translocationturk' backcross derivative translocation line carrying negative (WSMV-susceptible), and eight parental lines, were grown Wsm1 and with good bread baking properties (Wells et as a randomized complete block with three replications at Bozeman al., 1982). Karl has excellent grain protein content, grain and Conrad, MT, in 1998 and 1999. Treatments were arranged as a milling, and baking quality (Sears et al., 1991). Because split plot with populations as main plots and progeny and parents as of the limited size of the alien gene translocation, as subplots. The agronomic performance of resistant and susceptible lines was compared under inoculated and noninoculated conditions detected by in situ hybridization, the lack of virus accuto assess the effectiveness of the WSMV resistance gene and to deter-mulation, and the acceptable quality of parental lines, mine the effects of the Thinopyrum translocation in the absence of KS93WGRC27 shows promise as a reliable source of disease. A small but significant decrease in yield was observed for resistance to WSMV in a background with acceptable noninoculated resistant lines in contrast to susceptible lines. However, end-use quality. the yield range of resistant entries suggests that the recovery of paren-The Montana spring wheat breeding program develtal yield was possible. The resistance source was highly effective in oped advanced spring wheat progeny with and without limiting virus accumulation and yield losses to WSMV, resulting in the 4J s translocation using a polymerase chain reaction only a 5% yield reduction in resistant lines under inoculated conditions

To minimize the damaging effects of these pathogens, producers should apply glyphosate at least 2-3 weeks before planting GR wheat, as currently advised for GS cereals.

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