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Three polycross populations of smooth bromegrass (Bromus inermis Leyss.) derived by recurrent phenotypic selection for high seed weight averaged higher in seed weight and seedling vigor and lower in fertility index than five check varieties. Selection for high seed weight had little effect on mean performance or variability for traits other than seed weight and seedling vigor. Seed and forage yields were maintained at high levels.In average seed weight over 2 years, the three successive selected populations were, respectivdy, 6, 20, and 30% higher than the mean of two check clones selected to represent the mean of the initial material. Close agreement was obtained between space‐planted and seeded‐row tests for relative seed weight (r = .98). Phenotypic variance for seed weight increased with each successive cycle of selection.Selection for increased seed weight resulted in superior seedling vigor as measured by ability to emerge from a 5‐cm planting depth, weight per seedling, and seedling yield per unit area. The seedling vigor advantage of large‐seeded strains was greatest during early stages of seedling growth. Topcross progenies of 50 plants selected for high seed weight and seed set from cycle 3 were 45% higher in average weight per seedling 1 month after planting in the field than were five check varieties.

A small‐sample particle size indexing procedure was altered to require only 2.0 g of wheat (Triticum aestivum L. em Thell.) meal per determination. Particle size index (PSI) values were determined on a wide range of materials over a series of experiments and years. High repeatability in duplicate determinations, high correlations between locations, ability to differentiate lines of proven quality acceptance, and relatively low environmental influence indicated its reliance as a measure of kernel texture. A correlation of 0.83 between 56 selected F2 plants and their F3 bulk progenies grown in the subsequent season indicated a high heritability. The divergence of F3 population means resulting from selection of F2 extremes indicated a high degree of response to selection for PSI in early segregating generations. Application of the particle size indexing procedure to breeding materials in the MSU (Michigan State Univ.) hybrid wheat breeding program indicated a large genetic potential for selection. Genotypic and environmental correlations between PSI and protein percentage were small. The possibility of breeding higher protein pastry‐quality soft winter wheat cultivars is discussed.

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