Stability of ‘Saratoga’ Bromegrass Populations from Different Breeder Seed Syntheses, Locations of Seed Production, and Seed Maturities at Harvest1
- C. M. Rincker,
- J. G. Dean and
- R. G. May2
Information is not available on the extent of population shifts, if any, in synthetic cultivars of smooth bromegrass resulting from seed multiplication in diverse environments, methods of breeder seed synthesis, or seed maturity at harvest. Objectives of our research were to determine effects of two methods of breeder seed syntheses, three diverse locations of seed production, and three seed maturities at harvest upon the population stability of ‘Saratoga’ smooth bromegrass (Bromus inermis Leyss.). Polycross seed was produced in vegetatively established nurseries at Shafter and Tehachapi, Calif., and Prosser, Wash. At each location two breeder seed lots were synthesized using 1) equal parts of pure live seed from each of the 5 parental clones, or 2) portions equivalent to relative seed yields. These lots, plus similar blends produced at Ithaca, N.Y., were used to plant four isolated increase blocks at the three western locations to produce second generation seed harvested at early, optimum, or late maturity. The second generation seed lots, including the original breeder seed blends, were evaluated in a space-planted nursery at Prosser in 1978 and 1979. Four plant characteristics were measured: heading date, anthesis date, plant height, and rhizome spread after 2 years. Plants from second generation seed produced at Shafter tended to be taller with less rhizome spread than those from Prosser or Tehachapi. Otherwise there were no consistent trends to indicate that methods of synthesizing breeder seed or location of production affected the population characteristics. Maturity of seed at harvest had no effect on plant characteristics. Based on these results we concluded that even though the parental clones were significantly different, the Saratoga bromegrass synthetic, and perhaps other bromegrass synthetics, would be very stable under differing management and environmental conditions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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