Improvement of Seedling Vigor of Smooth Bromegrass (Bromus inermis Leyss.) by Recurrent Selection for High Seed Weight1
- C. R. Trupp and
- I. T. Carlson2
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .