Graduation date: 1981Three chemicals SD 55446, SD 55447 and WL 84245 were found to\ud induce male sterility in cultivars of wheat or triticale. Both SD 55446\ud and SD 55447 when applied at a concentration of 0.896 kg/ha resulted\ud in 90% male sterility. However, SD 55447 caused female sterility at\ud the same concentration either in single or split applications. Both\ud chemicals reduced plant height and grain yield and inhibited spike\ud emergence. The phytotoxic effects were reduced when the applications\ud were delayed until the early stage of spikelet formation.\ud A chemical x cultivar interaction was observed in both wheat and\ud triticale when the concentration of 0.67 kg/ha and/or 0.84 kg/ha of\ud SD 55446 were applied at the second node detectable of stem elongation\ud stage and the early stage of spikelet formation. The chemical induced\ud male sterility up to 98.8% depending on cultivars and concentrations\ud without influencing female fertility.\ud Using two genetic marker lines (blue aleurone) and two chemicals\ud SD 55446 and WL 84245, an estimate of the amount of induced and natural\ud out-crossing was obtained. Induced out-crossing was found to range\ud from 17% to 23% depending on the location. A higher percentage of out-crossing was noted with SD 55446 than WL 84245. Natural outcrossing\ud in two cultivars, Yamhill and Stephens, was found to be\ud less than one percent. The amount of induced and natural outcrossing\ud varied depending on the direction and distance from the\ud blue aleurone pollen source. No blue seed was obtained at a distance\ud beyond 20 meters from the pollinator.\ud All three chemicals induced more than 90% male sterility; however,\ud some female sterility was also observed. This latter factor, plus\ud other phytotoxicity, can be minimized by using optimum application\ud times and concentrations. However, these adverse effects coupled\ud with limited out-crossing in induced male sterile plots appear to\ud prohibit the use of these chemicals for large scale commercial hybrid\ud seed production
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