Patterns of amplified restriction fragment polymorphism in natural populations and corresponding seed collections of plains rough fescue (Festuca hallii)

Plains rough fescue ( Festuca hallii (Vasey) Piper) is a dominant native grass species in the Fescue Prairie region of North America that has undergone dramatic range reduction in the past century. Little is known about the genetic diversity of this species. The amplified restriction fragment polymorphism (AFLP) technique was applied to assess the comparative genetic diversity of six plains rough fescue populations in Manitoba and Saskatchewan and their corresponding seed collections. Three AFLP primer pairs were employed to screen 529 samples, representing about 30 samples each of reproductive tiller, vegetative tiller, and seed collected from each population. A total of 330 polymorphic AFLP bands were scored for each sample; their occurrence frequencies ranged from 0.01 to 0.99 and averaged around 0.47. Analysis of molecular variance revealed more than 90% of the total AFLP variation resided within natural populations (reproductive and vegetative tillers) and within seed samples. Four populations sampled from protected areas appear to have relatively lower within-population variation than two unprotected populations. Only 0.2% AFLP difference was revealed among the three tissue types examined. The tiller samples revealed slightly larger among-population variation than the seed samples and captured substantial associations of AFLP variation with population geographic distances. These findings are important for germplasm sampling for ex situ conservation, are useful for germplasm development for pasture seeding, and should facilitate the management of fragmented fescue populations.

Genetic relationships within and among Iberian fescues (Festuca L.) based on PCR-amplified markers

The genus Festuca comprises approximately 450 species and is widely distributed around the world. The Iberian Penninsula, with more than 100 taxa colonizing very diverse habitats, is one of its main centers of diversification. This study was conducted to assess molecular genetic variation and genetic relatedness among 91 populations of 31 taxa of Iberian fescues, based on several molecular markers (random amplified polymorphic DNA, amplified fragment length polymorphisms, and trnL sequences). The analyses showed the paraphyletic origin of the broad-leaved (subgenus Festuca , sections Scariosae and Subbulbosae, and subgenus Schedonorus ) and the fine-leaved fescues (subgenus Festuca, sections Aulaxyper, Eskia, and Festuca). Schedonorus showed a weak relationship with Lolium rigidum and appeared to be the most recent of the broad-leaved clade. Section Eskia was the most ancient and Festuca the most recent of the fine-leaved clade. Festuca and Aulaxyper were the most related sections, in concordance with their taxonomic affinities. All taxa grouped into their sections, except F. ampla and F. capillifolia (section Festuca), which appeared to be more closely related to Aulaxyper and to a new independent section, respectively. Most populations clustered at the species level, but some subspecies and varieties mixed their populations. This study demonstrated the value in combining different molecular markers to uncover hidden genetic relationships between populations of Festuca.

Systematic studies of Festuca (Poaceae) occurring in China compared with taxa in North America

Members of the genus Festuca in China were studied from an illustrated database developed using the DELTA (DEscription Language for Taxonomy) software package. The database includes the place of valid publication of scientific names; the location of type specimens when known; whether we have examined the type specimens; synonymy; information on habitat, distribution, subgeneric classification, and taxonomic notes; and approximately 200 images. Five subgenera and 58 species including aggregates are recognized. Six taxa are not assigned to a subgenus at this time. Species descriptions of 400–500 words were generated in Chinese and English and are available on the Internet at http://cdelta.ibcas.ac.cn and as a CD-ROM in English and Chinese from the first author. INTKEY has been used to produce parallel and diagnostic descriptions of 120–130 words for 58 species of the genus Festuca for the Flora of China treatment in English. INTKEY and other DELTA programs were used to assess taxa throughout the database and in a detailed study of 11 flat-leaved taxa that appear to have their centre of diversity in China. The awnless taxa from China that were considered belong to the genus Festuca, not Poa. All the flat-leaved Festuca studied are sufficiently morphologically unique to be treated as species distinct from any found in North America. Clustering and phylogenetic methodologies were used to assess subgeneric and sectional classifications. A new section is proposed, Parviglumae sect. nov.Key words: Festuca, Subulatae, DELTA, China, systematics.

Dupontia (Poaceae) in North America

Challenged by work on the Panarctic Flora project and apparent discrepancies in recent taxonomic treatments, the genus Dupontia was studied from herbarium specimens, including types and chromosome vouchers, and by numerical taxonomy, mapping the distribution of morphological characteristics, consideration of chromosome numbers, and field work in the Canadian Arctic. Our results using these techniques show random variability in many characters and differences in plant size that appear to be partly habitat related. The treatment of the genus has varied from the recognition of one variable species to three or more distinct species. Morphological characters, used in the literature to divide the genus Dupontia into more than one taxon, cannot be reliably applied to distinguish most North American plants. Continuous morphological variation in combination with high and variable ploidy levels, effective vegetative growth, and rare sexual reproduction suggests the use of a broad species concept. Until further evidence is available, our results support treating the genus as monotypic.Key words: Poaceae, Dupontia, morphology, chromosome numbers, conditional clustering, contingency tables.