Festuca Species Research Articles

Limited taxonomic value of palea intercostal characteristics in North American Festuca (Poaceae)

Morphology of the intercostal palea region of 34 Festuca species found in North America was investigated using scanning electron microscopy. Palea epidermal features are most diverse in the palea apical region and fully developed in florets approaching anthesis. The intercostal region has long cells 3–15 times longer than wide, with walls that vary from slightly to prominently thickened, and from almost straight to strongly undulate. This variation was observed among paleas collected from different locations and sometimes even on a single palea. The distribution of short cells, almost square in outline, among the long cells varied with species from solitary to paired and from abundant to sparse. Four forms of trichomes were recorded: papillae, hook trichomes, prickle hairs, and macrohairs, with one form usually predominating per species. Silicon was detected in some short cells and commonly in the tips of trichomes. A key to species groups is presented. Key words: scanning electron microscopy, palea, trichomes, silicon, epidermal features, Festuca.

Synaptonemal complex formation in two allohexaploid Festuca species and a pentaploid hybrid

Festuca arundinacea and Festuca gigantea are allohexaploids (2n=6x=42), that have bivalent pairing at metaphase I of meiosis. Analysis of the synaptonemal complexes of these species and of a pentaploid hybrid between F. gigantea and tetraploid Lolium perenne showed that initial synapsis in the allohexaploids is mostly between homologous chromosomes though some multivalents are formed, but in the hybrid most of the chromosomes associate as multivalents. It is concluded that the mechanism controlling bivalent formation in these species acts mainly at zygotene by restricting pairing to homologous chromosomes, but also at pachytene preventing cross-overs in the small number of homoeologous associations that have occurred. In the hybrid, where pairing control is ineffective, the mechanism fails at both stages.

TOLERANCE OF ORNAMENTAL GRASSES TO POSTEMERGENCE GRASS HERBICIDES

Ornamental grasses are popular landscape plants and often encounter turf encroachment or other grass weed problems. Several postemergence grass herbicides are available for use in turf and ornamentals and herbicide tolerance information is needed for ornamental grass species. Fifteen ornamental grasses including species from the genera Calamagrostis, Cortaderia, Eragrostis, Erianthus, Miscanthus, Sorghastrum, Spartina, Panicum and Pennisetum were field planted in Clemson, SC in May 1989 and Festuca species in November, 1989. Herbicide treatments were fenoxaprop-ethyl, fluazifop-P and sethoxydim at 0.4 kg a.i.·ha-1 applied 4 weeks after planting and an untreated control. Height and injury evaluations were taken at weekly intervals and plants were harvested 10 weeks after treatment. Fenoxaprop-ethyl treated Calamagrostis and Festuca species treated with all herbicides were the only treatments that were the same as untreated controls in terms of % injury, height and dry weight. Three ornamental Calamagrostis species were evaluated in a greenhouse study to determine the level of tolerance to fenoxaprop-ethyl at 0.4, 0.8, 1.6 and 3.2 kg a.i.·ha-1. No visual injury symptoms were seen on any treatments as compared to untreated controls but growth rates of the youngest leaves did vary among species shortly after treatment.

TOLERANCE OF ORNAMENTAL GRASSES TO POSTEMERGENCE GRASS HERBICIDES

Ornamental grasses are popular landscape plants and often encounter turf encroachment or other grass weed problems. Several postemergence grass herbicides are available for use in turf and ornamentals and herbicide tolerance information is needed for ornamental grass species. Fifteen ornamental grasses including species from the genera Calamagrostis, Cortaderia, Eragrostis, Erianthus, Miscanthus, Sorghastrum, Spartina, Panicum and Pennisetum were field planted in Clemson, SC in May 1989 and Festuca species in November, 1989. Herbicide treatments were fenoxaprop-ethyl, fluazifop-P and sethoxydim at 0.4 kg a.i.·ha-1 applied 4 weeks after planting and an untreated control. Height and injury evaluations were taken at weekly intervals and plants were harvested 10 weeks after treatment. Fenoxaprop-ethyl treated Calamagrostis and Festuca species treated with all herbicides were the only treatments that were the same as untreated controls in terms of % injury, height and dry weight. Three ornamental Calamagrostis species were evaluated in a greenhouse study to determine the level of tolerance to fenoxaprop-ethyl at 0.4, 0.8, 1.6 and 3.2 kg a.i.·ha-1. No visual injury symptoms were seen on any treatments as compared to untreated controls but growth rates of the youngest leaves did vary among species shortly after treatment.

Mode of Action of Herbicides Affecting Acetyl-CoA Carboxylase and Fatty Acid Biosynthesis

The mode of action of cyclohexane-l,3-dione-type (cycloxydim, clethodim, sethoxydim, tralkoxydim) and aryloxyphenoxypropanoate-type herbicides (diclofop, fenoxaprop, haloxyfop, fluazifop) is summarized in this review. Both herbicide classes, though structurally completely different, specifically block the same target enzyme i.e. the plastid acetyl-CoA carboxylase (ACC) (EC 6.4.1.2). Most members of the Poaceae are sensitive towards both herbicide groups, whereas other monocotyledonous plants as well as the dicotyledonous plants appear to be resistant. This resistance, which can be found on the level of whole plants, in isolated chloroplasts and also on the level of ACC-enzyme preparations, is apparently due to a modification of the target enzyme ACC. Within the sensitive grass family some members (Festuca and Poa species) are partially tolerant against both graminicide groups. In the case of cyclohexanedione herbicides the tolerance seems to be due to a reduced sensitivity of the target enzyme. In the case of aryloxyphenoxypropionic acid herbicides the tolerance is apparently based on a combined action of cytoplasmic factors (metabolization?) and a slightly reduced sensitivity of the target enzyme. From differences in the sensitivity of certain grasses against the two herbicide classes it is concluded that both graminicide groups bind to the same binding domaine of the ACC enzyme but possess different subsites. The consequences of the block of de novo fatty acid biosynthesis in the plastids of sensitive plants is the lack of glycerolipid and biomembrane formation which finally causes cell death in the meristematic tissues.

Cool‐Season Turfgrass Responses to Drought Stress1

As the supply of water available for turf irrigation becomes limited, it is important to identify water‐efficient and drought‐tolerant turfgrasses. To establish the critical soil water potential at which cool‐season turfgrasses begin to experience drought stress, the growth and quality responses of Poa pratensis L. ‘Baron’, Lolium perenne L. ‘Yorktown II’, Festuca rubra var. commutata Gaud. ‘Jamestown’ and Festuca ovina var. duriuscula (L.) Koch ‘Tournament’ drought stress were compared in a greenhouse study. Evapotranspiration (ET) rates were measured using weighing lysimeters containing undisturbed cores of mature turf growing in a silt loams oil. Tensiometers and electrical resistance blocks were installed in a separate set of eight lysimeters containing L. perenne to determine the relationship between water loss due to ET and soil water potential. The ET rates of all grasses were unaffected until the soil water potential reached −50 to −80 kPa. During further soil water depletion, ET rates declined and drought stress symptoms became apparent. Leaf water potential of P. pratensis and L. perenne decreased by 50 to 75% when soil water potential declined to −80 kPa, while that of Festuca species remained relatively constant to a soil water potential of −400 kPa. Based on the parameters measured, P. pratensis and L. perenne exhibited a more rapid decline in ET rate, quality, and leaf growth under moisture stress than the two Festuca species, which demonstrated greater ability to thrive with limited soil moisture.

The effect of cattle and sheep grazing on salt-marsh vegetation at Skallingen, Denmark

The aggregated effect of cattle and sheep grazing on Puccinellion maritimae and other salt-marsh vegetation has been studied together with changes in species composition, the percentage cover of each species, total cover and the percentage of bare ground, six years after grazing had been prevented by construction of experimental exclosures. The results of these experiments are discussed in relation to the natural development of the vegetation that occurred in a permanent plot in the ungrazed part of the salt marsh. Six years without grazing caused a marked increase in total cover and a dramatic reduction in the amount of bare ground. The species composition of the Puccinellia maritima community did not change during these six years, but all species increased in cover. Whereas Artemisia maritima migrated into the Festuca rubra community and only two species Festuca and Halimione portulacoides, increased in cover, all other species showed reduced cover and Salicornia europaea disappeared from the plot after six years without grazing. During the same period of time, three species, Salicornia europaea, Suaeda maritima, and Glaux maritima, disappeared from the plot in the ungrazed marsh as a result of natural development. During thirty-five years the vegetation originally dominated by Puccinellia maritima and Salicornia europaea has changed into a community dominated by Halimione portulacoides, whereas the grazed salt marsh is still dominated by Puccinellia maritima and Salicornia europaea.

Hardening Behavior, Winter Survival, and Forage Productivity of Festuca Species and Cultivars in Subarctic Alaska1

Marginal to inadequate winterhardiness is a continuing problem in grasses used for forage production and turf purposes in subarctic, southcentral Alaska. Cultlvars or strains from various latitudinal sources within five Festuca species or subspecies were compared in field plots in Knik silt loam soil (coarse‐silty over sandy or sandy‐skeletal, mixed, nonacid Typic Cryorthent) over 18 experiment‐years for relative winterhardiness and forage production. Also three red fescues (F. rubra L.) of diverse latitudinal adaptation and differing widely in winterhardiness here (cvs. Arctared, Duraturf, Illahee) were compared for changes dry matter concentration in crown tissues during winterhardening, food reserves stored by onset of winter, and winter survival of plants left in the field. All broad‐leaved fescues evaluated; including meadow fescue (F. elatior L.) strains ‘Bottnia II’, ‘Tammisto’, ‘An‐2356’, and commercial, and tall fescue (F. arundi. nacea Schreb.) cv. Alta; winterkilled completely during the first or second winter of each test. Fine‐leaved fescues generally deficient in winterhardiness included ‘Highlight’ and commercial chewings fescue (F. rubra var. commutata Gaud.), ‘Durar’ hard fescue [F. ovina var. duriuscula (L.) Koch], and red fescue cultivars from the conterminous 48 states (‘Ranier’, ‘Pennlawn’, Illahee) and from Canada (‘Boreal’, ‘Olds’). Duraturf, selected in Canada from germplasm of Scandinavian origin, was the most winterhardly of introduced cultivars, but it was not as hardy or productive of forage as the extremely winterhardy, subarctic adapted Arctared, developed in Alaska. Hardiness ranking of red fescue cultivars was Arctared > Duraturf > Boreal ≥ Olds > Ranier = Pennlawn > lllahe. Arctared, selected for turf characteristics, produced as much forage as ‘Polar’ bromegrass (predominantly Bromus inermis Leyss ✕ B. pumpellianus Scribn.), an Alaskan cultivar selected for forage productivity. Superior winterhardines of Arctared was associated with northernmost adaptation, highest percent dry matter in crowns, highest levels of stored reserves, and slowest expression of reserves as etiolated growth. Poorest winter survival occurred with southernmost‐adapted Illahee which was lowest in percent dry matter in crowns and stored lowest level of food reserves. Duraturf, of intermediate‐latitudinal adaptation, was intermediate in crown moisture, reserve storage, and winter survival.

The Effect of Droughting on Varieties and Ecotypes of Lolium, Dactylis and Festuca

(1) Cultivars and populations of Lolium, Dactylis and Festuca species were grown under contrasting soil moisture regimes in the glasshouse. Dry matter production, leaf extension and tillering were measured during treatment and during subsequent recovery periods. (2) L. perenne was least affected by drought and D. glomerata was most affected. Regrowth after drought was stimulated by previous water shortage in L. perenne and D. glomerata. (3) Populations from dry habitats, and cultivars which tolerated drought, usually produced less herbage dry matter than cultivars and populations from moist habitats. Cultivars and populations did not differ significantly in response to drought, during the droughting period, though populations of L. perenne and L. multiflorum from dry habitats recovered from drought more rapidly than did those from moist habitats.

A Meiotic Examination of Lolium multiflorum Lam. × Festuca arundinacea Schreb. F 1 Hybrids 1

An understanding of the genetic and cytogenetic relationships of the Lolium and Festuca species would facilitate the utilization of their intergeneric hybrids in breeding efforts to improve the parental species. Meiotic chromosomal behavior was examined in two Lolium multiflorum Lam. × Festuca arundinacea Schreb. F1 hybrids to provide more complete data on the meiotic process and to determine whether such information is useful in providing more specific knowledge concerning the transfer of genetic information in these crosses. The hybrids displayed similar frequencies of bivalents and trivalents per cell but differed significantly in the frequencies of univalents and quadrivalents at Metaphase I. The number of lagging univalents observed at Anaphase I corresponded well with the number of micronuclei per dyad at interkinesis. The number of quartet micronuclei was similar in the hybrids and indicated that the result of meiosis is similar for the hybrids despite the differences in initial chromosomal pairing frequencies. Dicentric bridges were also observed at Anaphase I and II, indicating structural heterogeneity within the paired chromosomes. The current analysis did not indicate whether the paracentric inversions involved L. multiflorum : F. arundinacea chromosomal pairs or F. arundinacea : F. arundinacea pairs. The distribution of lagging univalents in Anaphase I cells with and without dicentric bridges separated two groups of chromosomes relative to pairing probability present in these hybrids. The bivalents appeared to involve basically the same chromosomes in all cells, whereas the univalents and/or multivalents were drawn from a different group of chromosomes.

EFFECT OF WATERING REGIME ON YIELD, WATER USE AND LEAF CONDUCTANCE OF SEVEN FESTUCA SPECIES WITH CONTRASTING LEAF RIDGING

SummarySeedlings of seven Festuca species with contrasting leaf surface morphology were grown in pots with three different watering regimes to simulate full irrigation, intermittent soil moisture stress or prolonged soil moisture stress.When harvested at a similar growth stage, plants subjected to the greatest stress had the least shoot dry matter. Differences between treatments were greatest in the fastest growing plants, e.g. F. arundinacea cv. S.170. At harvest, mean transpiration rate was lowest in plants from the least stressed treatment and in species with the flattest leaf surfaces e.g. F. drymeja and F. gigantea. Whether or not allowance was made for the effect of the convolutions of the leaf surfaces in increasing effective leaf surface area, the ranking of the species for transpiration rate per unit leaf area under well watered conditions was the same.Overall water use efficiency (WUE) was greatest in plants subjected to prolonged soil moisture stress (383 mg shoot dry matter per 100 g of water transpired) and least in those which were intermittently stressed (301 mg per 100 g). WUE was also greater for the flatter leaved species, the greatest being for F. gigantea (437 mg per 100 g) and least for F. scariosa (275 mg per 100 g). These variations in water use efficiency were not closely related to daily maximum stomatal conductance or to stomatal density of the leaves.WUE was not highly correlated with any of the other parameters measured. At best, 46 % of the variation was associated (negatively) with the final rate of transpiration which in turn was closely correlated (positively) with the degree of adaxial leaf surface ridging.

Mycorrhizal fungi associated with Festuca in the western United States and Canada

Vesicular–arbuscular mycorrhizal infection and associated mycorrhizal fungi were examined for Festuca viridula, Festuca idahoensis, Festuca scabrella, Festuca thurberi, Festuca ovina, and Festuca arizonica occurring in Festuca-dominated grasslands in the western United States and Canada. All plants were mycorrhizal. Nearly all had mycorrhizal infection in 75% or more of their fine root length. Although levels of infection were consistently high, spore numbers were generally low. No differences in the degree of infection between Festuca species or habitats were observed.Eleven mycorrhizal fungi were identified and ranked by decreasing frequency as follows: Glomus fasciculatus, Glomus tenuis, Gigaspora calospora, Acaulospora laevis, Glomus macrocarpus var. macrocarpus, Glomus microcarpus, Acaulospora scrobiculata, Glomus mosseae, Glomus macrocarpus var. geosporus, Sclerocystis rubiformis, and an unidentified Acaulospora species. It was common to find two or more species infecting an individual plant. The mean number of fungal associates per community site ranged from 2.7 species for F. idahoensis to 5.0 species for F. arizonica. We found no evidence for specificity of any of the mycorrhizal fungi for any particular Festuca host.

Qualitative effects of asulam and glyphosate on swards dominated by bracken (Pteridium aquilinum (L.) Kuhn)

AbstractThe initial effect on the underlying sward of spraying bracken with 4.5 kg ha−1 a.i. asulam or 2.0 kg ha−1 a.i. glyphosate was to cause some damage which was greater if glyphosate was used rather than asulam or if treatment was carried out in August rather than in July. Agrostis species were especially susceptible while Festuca species were resistant. The recolonization of areas of bare ground after spraying was primarily by Holcus moliis, Anthoxanthum odoratum, Galium hercynicum and Potentilla erecta, but the population of the latter two species decreased as Agrostis became reestablished. If Digitalis purpurea, Urtica dioica or Cirsium arvense were present originally, heavy infestations developed following the use of asulam, with a smaller increase after glyphosate spraying. In all cases, by the end of three years after treatment, grasses occupied a greater area of the sward in treated than in control plots.

STUDIES IN FESTUCA. 11. INTERRELATIONSHIPS OF SOME PUTATIVE DIPLOID ANCESTORS OF THE POLYPLOID BROAD‐LEAVED FESCUES

SUMMARYThe relationships of six diploid Festuca species were studied: Section Montanae: F. donax, drymeja, altissimaScariosae: F. scariosaBovinae: F. pratensisOvinae: F. polesica.The criteria used were ability to hybridize, and fertility and meiotic chromosome pairing in the F1 hybrids. The closest affinity discovered was amongst the species within Section Montanae, there was also a strong affinity between these and F. scariosa, and a weak link with F. pratensis and F. polesica. The results are briefly discussed from the standpoint of species‐relationships in Festuca and Lolium.

Didymella festucae and its imperfect state, Phleospora idahoensis, on Festuca species in western North America

Didymella festucae (Weg.) Holm (imperfect state Phleospora idahoensis Sprague), endemic on native Festuca spp. in western North America and reported from a few arctic–alpine regions in Europe, is the cause of a major destructive stem eyespot disease in seed crops of red fescue, Festuca rubra L., in the Peace River region of northern Alberta and British Columbia. The original description of the disease as a leaf and pedicel blight requires modification because eyespots, staining, and later extensive blackening of culms and inflorescences are the common symptoms. The size range of ascospores, 18–63 × 4.5–14.0 microns (μ), and conidia, 18–105 × 3.0–9.0 μ, considerably exceeded dimensions previously given for D. festucae from Europe and P. idahoensis from North America and Europe. Although the morphology of fungal structures was highly variable, dimensions of ascospores and conidia from the Swiss type material fell into the size range established for North American material. Swiss type material of the perfect stage also yielded typical conidia of P. idahoensis. Microconidia are uncommon in natural material and cultures and their function is uncertain. Pathogenicity tests confirmed the wide natural-host range. Host immunity or physiologic specialization of the fungus is not indicated, but there is some evidence that isolates differ in degree of pathogenicity. For the present, P. idahoensis is suitably accommodated in Phleospora and D. festucae in Didymella, although both genera are ill-defined, requiring further study.

Two New Species of Cyst Nematode, Heterodera Mani N. Sp. and H. Iri N. Sp., From Northern Ireland

Two new species of cyst nematode occurring on grasses in Northern Ireland are described and illustrated. Both, having bifenestrate bullate cysts, belong to the avenae species-group. H. mani n. sp. infests Lolium, Dactylis and Festuca species. It differs from H. avenae Woll., 1924 in that the larvae have deeply concave stylet-knobs and four lines in the lateral field; the more rounded females have shorter stylet-knobs; the males have smaller heads and longer spicules and the cysts are more rounded and possess a distinct underbridge. H. iri n. sp. parasitizes Agrostis sp. and differs from both H. avenae and H. mani in that the larvae possess exceptionally long tails (true-tail and clear-tail averaging 94 μ and 62 μ respectively) ; the cysts are more spheroidal, much lighter in colour, have a thin matt-white subcrystalline layer and a strong underbridge. Unlike H. avenae neither new species attacks cereals.

SOME EFFECTS OF MECHANICAL TREATMENTS AND SURFACE SOWING ON ROUGH HILL GRAZINGS

ABSTRACTAn experiment involving two adjacent, but contrasting, sites was conducted to examine the effect of using the rotary cultivator and the forage harvester as instruments in the improvement of indigenous hill swards at 1600 ft alt. by surfaee sowing. On a dry sward dominated by Nardus/ Festuca, both an autumn and a spring rotary cultivation were necessary to give the highest number of established seedlings. This also resulted in the greatest improvement in hotanieal composition. On a wetter Molinia‐dominant sward, two separate rotary cultivations did not increase seedling establishment, compared with a single rotary cultivation. On the dry site, an autumn and a spring topping with a forage harvester established fewer seedlings, but on the wetter site the difference as compared with rotary‐cultivation treatments was not significant. On this wetter site, topping by forage harvester gave an improved botanical composition by effecting a reduction in Festuca species to give a sward dominated by Agrostis and timothy.

Cercosporella herpotrichoides Fron on Gramineous Hosts in Ireland

CLIMATIC factors are known to affect greatly the prevalence of cereal eyespot caused by Cercosporella herpotrichoides, leading to great variation in disease intensity in different seasons. The work of Sprague1 shows that susceptibility of various gramineous species is a function of the environment; many grasses became infected in near optimum greenhouse conditions, whereas only a few species were found to be naturally infected during an intensive 7-year search in the north-western United States. These included Bromus and Agropyron species. Agropyron repens, however, was uninfected in the field though susceptible in the greenhouse. The very pronounced climatic effect on disease incidence and on the host range of the causal agent is shown by the prevalence of eyespot on spring-sown cereals in Scotland compared with the drier parts of southern England2, and on oat crops in the humid conditions prevalent in Ireland3. There are few records of the natural occurrence of Cercosporella herpotrichoides on grasses in Europe, but in Holland the organism was isolated from Alopecurus myosuroides, Poa pratensis and Apera spica-venti4. Hosts found in Finland included Festuca and Poa species as well as Alopecurus pratensis and Agropyron repens5, while an isolate was obtained from Agrostis stolonifera at Rothamsted6.