| Hybridization of Triticum with 3 Agropyron
species J. SCHULZ - SCHAEFFER1/ Department of Plant and Soil Science Montana State College Bozeman, Montana, U. S. A. In a system of grassland - wheat farming there is a reluctance to plow established grass stands and to establish new stands of grass. Easily established grasses would remove some of the hazards involved and provide greater flexibility in shifting from small grain to grass. The small seed of present dryland grasses may limit the coditions under which satisfactory stands can be obtained. A program was initiated in an effort to improve tall, intermediate, and pubescent wheatgrass by intergeneric crossing with wheat. The objectives are to develop wheatgrass strains with large, free-threshing seeds with reduced tendency for sod binding. An initial phase of this program was to establish hybrids between Triticum and Agropyron species, During the summer of 1961 plants of 8 wheat species were crossed with plants of 2 Agropyron intermedium strains, one A. trichophorum strain, and 3 A. elongatum strains. The seed sources of these wheat and wheatgrass strains are listed alphabetically in Table 1. The crossing results are recorded in Table 2. The percentage of crossability is based on the appearance of the F1 plants in the greenhouse. Only grass - like plants are considered to be true hybrids. Plants with typical annual characteristics and wheat - like morphology are considered to have originated from selfed seed. It is realized that this procedure may not account for some of the resulting hybrids. The hybrids are listed in this table according to their percentage of crossability. The most successful crosses were T. persicum x A. trichophorum and T. timopheevi x A. elongatum. For the evaluation of crossing results in intergeneric hybridisation it is extremely important to consider the conditions and techniques used. For hand emasculation and pollination of the 1961 Bozeman crosses untrained labor (high school girls) was used. The crosses were accomplished during the 18 day period of July 7 to July 24, 1961. The range of maximum daily temperatures was 75 to 90oF with a mean maximum of 83.8oF. Minimum relative humidity was down to 25% with a range of minimum relative humidity of 25 - 40%. The low humidity may account in part for the low crossability. ZENNYOZI 1959 (WIS 9 - 10) and others reported higher percentages of crossability in similar intergeneric crosses. |