Long-Term Grazing Effects on Genetic Variability in Mountain Rough Fescue

Abstract

Festuca campestris Rydb. (mountain rough fescue) is a dominant grass species in the montane grasslands of western Canada. Little is known about the genetic diversity of this plant and the effects of long-term grazing on the genetics of populations. The amplified fragment length polymorphism (AFLP) technique was applied to compare the genetic diversity of fescue plants at adjacent grazed and protected areas for 3 populations spread across a longitudinal range: Stavely in the foothills, Milroy in the Rocky Mountain trench, and Goose Lake on the interior plateau. Five AFLP primer pairs were used to screen the tiller samples of about 39 plants in each grazed (or ungrazed) area, and 139 polymorphic AFLP bands were scored for each individual sample. These scored bands had frequencies ranging from 0.03 to 0.98 with an average of 0.56. About 81% of the total AFLP variation resided within the populations. The Goose Lake population had the lowest level of AFLP variation, but genetically was the most distinct. Four AFLP bands were possibly associated with chromosomal segments significant for grazing resistance. Comparisons of AFLP variation between grazing and nongrazing samples revealed variable and relatively small impacts of the long-term grazing on the genetic diversity of the grazed populations. The AFLP variation of grazed samples was 1.5% lower at Goose Lake, 2.2% higher at Milroy, and not different at Stavely. If developing diverse germplasm for rangeland seedings is desired, one should sample across geographic space rather than combining materials with and without historical grazing pressure. Resumen Festuca campestris Rydb. (''Mountain rough fescue'') es una especie de gramínea dominante de los pastizales montañ osos del oeste de Canadá. Poco se sabe acerca de la diversidad genética de esta planta y los efectos del apacentamiento a largo plazo sobre la genética de las poblaciones. Se aplicó la técnica de polimorfismo de la longitud de los fragmentos amplificados (AFLP) para comparar la diversidad genética de plantas de ''Fescue'' de á reas adyacentes apacentadas y sin apacentar (protegidas) para tres poblaciones distribuidas a lo largo de un gradiente longitudinal: Stavely en el pie de la montañ a, Milroy en la trinchera de las Montañ as Rocallosas y Goose Lake en la meseta interior. Cinco pares de primers AFLP fueron usados para examinar las muestras de hijuelos de aproximadamente 39 plantas de cada á rea, apacentada y sin apacentar y en cada muestra individual 139 bandas polimó rficas AFLP fueron calificadas. Estas bandas calificadas tuvieron frecuencias que variaron de 0.03 a 0.98, con un promedio de 0.56. Aproximadamente 81% de la variació n total de AFLP residió dentro de las poblaciones. La població n de Goose Lake tuvo el menor nivel de variació n de AFLP, pero genéticamente fue la mas distinta. Cuatro bandas AFLP posiblemente estuvieron asociadas con segmentos cromosó micos significativos para la resistencia al apacentamiento. Comparaciones de la variació n de AFLP entre muestras apacentadas y no apacentad...

Genetic Risk Assessment of a Threatened Remnant Population of Hairy Prairie-Clover (Dalea villosa var. villosa) in the Canadian Prairie

“…are both highly outcrossing, being pollinated by a diversity of bee and fly species [45]. Such a high level of AFLP polymorphism is expected for an outcrossing plant species [46] and is compatible with those AFLP findings reported in other outcrossing plant species native to North America [27][28][29]47,48]. …”

“…The AFLP markers [25], although scored dominantly (i.e., without distinction between homozygotes and heterozygotes) and not always homologous [26], has been widely applied to assess genetic variability in many plant species and is a robust, highly effective tool for poorly known plants [27][28][29]. The specific objectives of this study were: (1) to assess genetic variation and spatial structure within the remnant hairy prairie-clover population and (2) to evaluate the associations of genetic variation with patch characteristics such as patch size and perimeter.…”

Heavy grazing effects on stem elongation and internode allometry: Insights from a natural pasture grass

“…Our findings that LHG dramatically reduces the ultimate individual size, specifically the length of each internode, during the peak‐growth season are consistent with the results of previous studies conducted in multiple types of grasslands (James et al., ; Koerner, Collins, Blair, Knapp, & Smith, ). Theoretically, plant phenotypic plasticity, such as the decrease in stem elongation induced by LHG, is an important mechanism for grazing avoidance in plants that experience grazing (Fu, Thompson, Willms, & Mackay, ; McKinney & Fowler, ).…”

Genetic variation in remnant Festuca hallii populations is weakly differentiated, but geographically associated across the Canadian Prairie

“…After electrophoresis of the amplified DNA fragments, the gel was transferred to Whatman 3MM paper, dried on a gel dryer for 2 h at 80°C and exposed to Kodak BIOMAX film at −80°C for 1–7 days depending on the signal intensity. Based on previous AFLP analysis of Festuca campestris (Fu et al. 2005; Qiu et al.…”