VISUAL SELECTION FOR FORAGE YIELD IN WINTER-WHEAT

Winter wheat (Triticum aestivum L.) is used as both a grain and forage crop in the southern Great Plains, but wheat breeding programs traditionally emphasize grain characteristics when evaluating experimental strains. Forage-yield tests of large segregating populations are expensive and often unfeasible due to limited seed supply in early generations. Therefore, accurate visual prediction of forage yield potential from small plots would appeal to breeders. The objectives of this study were to measure the response to bidirectional visual selection for traits associated with forage yield based on a season-long index, and to determine the correlated response in grain yield. Twelve lines were divergently selected (six lines in each direction) from each of three F4 populations in the field. Ratings were based on leaf size, tillering capacity, canopy height, and growth habit. A prostrate growth habit was interpreted as undesirable for forage yield potential. The 36 selections and their parents were tested in the F5 (1988-1989) and F6 (1989-1990) generations. The high-selection group exceeded the low-selection group for fall forage yield (measured prior to winter dormancy) in five of six population-years. That trend was not observed for winter forage yield measured between dormancy and jointing. Visual selection for traits associated with forage yield did not produce a correlated change in grain yield. This study supports fall forage yield as a useful selection criterion in winter wheat breeding programs.