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This article in AJ

  1. Vol. 73 No. 4, p. 716-720
     
    Received: Sept 29, 1980


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doi:10.2134/agronj1981.00021962007300040036x

Germination-Temperature Profiles for Idaho and Sheep Fescue and Canby Bluegrass1

  1. J. A. Young,
  2. R. A. Evans,
  3. R. E. Eckert and
  4. R. D. Ensign2

Abstract

Abstract

Sheep fescue (Festuca ovina L.), Idaho fescue (F. idahoensis Elmer), and Canby bluegrass [Poa canbyi (Scribn.) Piper] are valuable forage species native on western rangelands. The success of artificial or natural revegetation of degraded or disturbed rangeland with these native species is partially dependent on understanding their germination and seedbed ecology. Germination tests were conducted at 55 regimes of constant and alternating temperatures. Constant temperatures were at 0, 2, and 5 C degree increments from 5 through 40 C. Alternating temperature regimes consisted of 16 hours in 24 at each constant temperature and 8 hours in 24 at each higher constant temperature. The germination from these 55 temperature profiles was used to construct quadratic response surfaces giving estimated percent germination with confidence intervals for each seed source tested. A series of germination profile characteristics was generated from these response surfaces to help interpret the germination response of the seeds to temperature. There were significant (P=0.01) differences in mean germination among the seed sources tested. ‘Covar’ sheep fescue had the highest mean germination, with most of the Idaho fescue sources intermediate and ‘Canbar’ Canby bluegrass lowest in germination. Covar sheep fescue was the only source tested that germinated above 76% at many temperature regimes. Most of the sources tested had maximum germination in the 51 to 75% range. Optimum germination, defined as that not lower than the maximum and its confidence interval (P=0.01), occurred around 15/20 C (15 C for 16 hours and 20 C for 8 hours) for the Idaho fescue sources but extended to lower temperatures for Covar sheep fescue and Canbar Canby bluegrass. Synthetic varieties of Idaho fescue had higher germination at warmer and more widely fluctuating temperatures than the other two species. In relation to seedbed temperatures monitored in field studies, Covar sheep fescue had the highest germination at moderate and colder-than-moderate seedbed temperatures. The synthetic varieties of Idaho fescue had the highest germination at warmer-than-moderate seedbed temperatures.

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