Explore the vast range of titles available.

Background Cultivated hexaploid oat (Common oat; Avena sativa ) has held a significant place within the global crop community for centuries; although its cultivation has decreased over the past century, its nutritional benefits have garnered increased interest for human consumption. We report the development of fully annotated, chromosome-scale assemblies for the extant progenitor species of the A s - and C p -subgenomes, Avena atlantica and Avena eriantha respectively. The diploid Avena species serve as important genetic resources for improving common oat’s adaptive and food quality characteristics. Results The A. atlantica and A. eriantha genome assemblies span 3.69 and 3.78 Gb with an N50 of 513 and 535 Mb, respectively. Annotation of the genomes, using sequenced transcriptomes, identified ~ 50,000 gene models in each species—including 2965 resistance gene analogs across both species. Analysis of these assemblies classified much of each genome as repetitive sequence (~ 83%), including species-specific, centromeric-specific, and telomeric-specific repeats. LTR retrotransposons make up most of the classified elements. Genome-wide syntenic comparisons with other members of the Pooideae revealed orthologous relationships, while comparisons with genetic maps from common oat clarified subgenome origins for each of the 21 hexaploid linkage groups. The utility of the diploid genomes was demonstrated by identifying putative candidate genes for flowering time (HD3A) and crown rust resistance ( Pc 91). We also investigate the phylogenetic relationships among other A- and C-genome Avena species. Conclusions The genomes we report here are the first chromosome-scale assemblies for the tribe Poeae, subtribe Aveninae. Our analyses provide important insight into the evolution and complexity of common hexaploid oat, including subgenome origin, homoeologous relationships, and major intra- and intergenomic rearrangements. They also provide the annotation framework needed to accelerate gene discovery and plant breeding.

A taxonomic revision of Trisetum Pers. sect. Trisetum is presented. We include descriptions and synonyms of each taxon from a study of 894 vouchers from 45 herbaria. Detailed morphometric descriptions, illustrations, distribution maps, an identification key, and habitat data are given for each taxon. Morphometric variation of the main characters is shown by box plots. Thirty-one names are lectotypified. Two neotypes are designated. We recognize eight species of Trisetum in the section: T. alpestre (Host) P. Beauv., T. altaicum Stephan ex Roshev., T. bertolonii Jonsell, T. flavescens (L.) P. Beauv., T. fuscum Schult., T. glaciale (Bory) Boiss., T. gracile (Moris) Boiss., and T. laconicum Boiss. & Orph. Two infraspecific taxa of T. flavescens are recognized (T. flavescens subsp. flavescens and T. flavescens subsp. griseovirens (H. Lindb.) Dobignard). Six of the eight species of Trisetum sect. Trisetum are endemic to the different European mountain ranges, while T. altaicum grows in the Altai and Tian Shan Mountains, and in the mountains of northern Mongolia and southern Russia, and T. flavescens is widespread in temperate regions of Europe, western Asia, and northern Africa. Vegetative propagation by pseudoviviparism is observed for the first time in specimens of T. flavescens subsp. flavescens.

A taxonomic revision of Trisetum sect. Sibirica is presented. We include descriptions and synonyms of each taxon from a study of 450 vouchers from 35 herbaria. Detailed morphometric descriptions, illustrations, distribution maps, identification key, and habitat data are given for each taxon. An identification key for all taxa of Trisetum sect. Sibirica is provided. Morphometric variation of the main characters is shown by box plots. Six names are lectotypified. We recognize six species of Trisetum in the section: T. aeneum, T. bifidum, T. henryi, T. scitulum, T. sibiricum, and T. turcicum. Two infraspecific taxa of T. sibiricum are recognized (T. sibiricum subsp. sibiricum and T. sibiricum subsp. litorale), while T. pauciflorum, T. sikkimense, and T. umbratile are reduced to synonyms of T. sibiricum subsp. sibiricum. Four of the six species of Trisetum sect. Sibirica are endemic to Eastern Asia and New Guinea, while T. turcicum grows in Turkey, the Caucasus, and Northern Iran, and T. sibiricum is widespread from Eastern Europe to Alaska and Canada.

A taxonomic revision of Trisetum Pers. sect. Trisetum is presented. We include descriptions and synonyms of each taxon from a study of 894 vouchers from 45 herbaria. Detailed morphometric descriptions, illustrations, distribution maps, an identification key, and habitat data are given for each taxon. Morphometric variation of the main characters is shown by box plots. Thirty-one names are lectotypified. Two neotypes are designated. We recognize eight species of Trisetum in the section: T. alpestre (Host) P. Beauv., T. altaicum Stephan ex Roshev., T. bertolonii Jonsell, T. flavescens (L.) P. Beauv., T. fuscum Schult., T. glaciale (Bory) Boiss., T. gracile (Moris) Boiss., and T. laconicum Boiss. & Orph. Two infraspecific taxa of T. flavescens are recognized (T. flavescens subsp. flavescens and T. flavescens subsp. griseovirens (H. Lindb.) Dobignard). Six of the eight species of Trisetum sect. Trisetum are endemic to the different European mountain ranges, while T. altaicum grows in the Altai and Tian Shan Mountains, and in the mountains of northern Mongolia and southern Russia, and T. flavescens is widespread in temperate regions of Europe, western Asia, and northern Africa. Vegetative propagation by pseudoviviparism is observed for the first time in specimens of T. flavescens subsp. flavescens.

A taxonomic treatment of Trisetum Pers. for South America, is given. Eighteen species and six varieties of Trisetum are recognized in South America. Chile (14 species, 3 varieties) and Argentina (12 species, 5 varieties) have the greatest number of taxa in the genus. Two varieties, T. barbinode var. sclerophyllum and T. longiglume var. glabratum, are endemic to Argentina, whereas T. mattheii and T. nancaguense are known only from Chile. Trisetum andinum is endemic to Ecuador, T. macbridei is endemic to Peru, and T. foliosum is endemic to Venezuela. A total of four species are found in Ecuador and Peru, and there are two species in Venezuela and Colombia. The following new species are described and illustrated: Trisetum mattheii Finot and T. nancaguense Finot, from Chile, and T. pyramidatum Louis-Marie ex Finot, from Chile and Argentina. The following two new combinations are made: T. barbinode var. sclerophyllum (Hack, ex Stuck.) Finot and T. spicatum var. cumingii (Nees ex Steud.) Finot. A key for distinguishing the species and varieties of Trisetum in South America is given. The names Koeleria cumingii Nees ex Steud., Trisetum sect. Anaulacoa Louis-Marie, Trisetum sect. Aulacoa Louis-Marie, Trisetum subg. Heterolytrum Louis-Marie, Trisetum subg. Isolytrum Louis-Marie, Trisetum subsect. Koeleriformia Louis-Marie, Trisetum subsect. Sphenopholidea Louis-Marie, Trisetum malacophyllum Steud., Trisetum variabile E. Desv., and Trisetum variabile var. virescens E. Desv. are lectotypified. /// Se realizó un estudio taxonómico del género Trisetum en América del Sur. Se reconoció 18 especies y 6 variedades sudamericanas de Trisetum. Chile (14 especies, 3 variedades) y Argentina 12 especies, 5 variedades) poseen el mayor número de taxones del género Trisetum. Dos variedades, T. barbinode var sclerophyllum y T. longiglume var glabratum, son endémicos de Argentina, mientras T. mattheii y T. nancaguense se conocen sólo para Chile. Cuatro especies se encuentran en Ecuador y Perú y dos especies en Venezuela y Colombia. Trisetum andinum es endémica del Ecuador, T. macbridei es endémica del Perú, y T. foliosum es endémica de Venezuela. Se describen e ilustran las siguientes nuevas especies: Trisetum mattheii Finot y T. nancaguense Finot, de Chile, y T. pyramidatum Louis-Marie ex Finot, de Chile y Argentina. Se establecen las siguientes dos nuevas combinaciones: T. barbinode var sclerophyllum (Hack. ex Stuck.) Finot y T. spicatum var cumingii (Nees ex Steud.) Finot. Se entrega una clave para separar las especies y variedades de Trisetum en Sudamérica. Los nombres Koeleria cumingii Nees ex Steud., Trisetum sect. Anaulacoa Louis-Marie, Trisetum sect. Aulacoa Louis-Marie, Trisetum subg. Heterolytrum Louis-Marie, Trisetum subg. Isolytrum Louis-Marie, Trisetum subsect. Koeleriformia Louis-Marie, Trisetum subsect. Sphenopholidea Louis-Marie, Trisetum malacophyllum Steud., Trisetum variabile E. Desv., y Trisetum variabile var virescens E. Desv. fueron lectotipificados.

A taxonomic treatment of Trisetum, Peyritschia, and Sphenopholis for Mexico and Central America is given. In Mexico and Central America four species of Peyritschia, two species of Sphenopholis, and 17 species of Trisetum s. str. are recognized. Peyritschia deyeuxioides and P. pringlei range from Mexico to Ecuador, P. koelerioides is found in southern Mexico to Guatemala, and P. humilis is endemic to Mexico. Sphenopholis obtusata ranges from Canada to the U.S.A. and Mexico, whereas S. interrupta is found in the southwestern U.S.A. and Baja California. Mexico. Mexico has the largest number of Trisetum species at 15, and nine of these are endemic. Five species of Trisetum are found in Guatemala, three in Costa Rica and Panama, and a single species is found in Honduras and the Dominican Republic. A new subgenus Deschampsioidea (Louis-Marie) Finot in Trisetum is proposed. Four new species of Trisetum from Mexico are described and illustrated: T. durangense Finot & P. M. Peterson, T. martha-gonzaleziae P. M. Peterson & Finot, and T. spellenbergii Soreng, Finot & P. M. Peterson (all in subg. Deschampsioidea); and T. ligulatum Finot & Zuloaga (in subg. Trisetum, sect. Trisetaera). Keys for the genera, subgenera, sections, and species of Trisetum, Peyritschia, and Sphenopholis that occur in Mexico and Central America are given. The names Trisetum gracile E. Fourn. and Trisetum subsect. Deschampsioidea Louis-Marie are lectotypified. /// Se presenta un tratamiento taxonómico de los géneros Trisetum, Peyritschia y Sphenopholis para México y América Central. Cuatro especies de Peyritschia, dos especies de Sphenopholis y 17 especies de Trisetum s. str. fueron reconocidas en México y Centroamérica. Peyritschia deyeuxioides y P. pringlei habitan desde México a Ecuador, P. koelerioides se encuentra desde el sur de México hasta Guatemala y P. humilis es endémica de México. Sphenopholis obtusata se encuentra en Canadá, EE. UU. y México, mientras S. interrupta habita el sudoeste de EE. UU. y Baja California, México. México posee el mayor número de especies de Trisetum, 15 especies, nueve de ellas endémicas. Cinco especies de Trisetum se encuentran en Guatemala, tres en Costa Rica y Panamá y sólo una en Honduras y República Dominicana. Se propone un nuevo subgénero Deschampsioidea (Louis-Marie) Finot en Trisetum. Cuatro nuevas especies de Trisetum de México son descritas e ilustradas: T. durangense Finot & P. M. Peterson, T. martha-gonzaleziae P. M. Peterson & Finot y T. spellenbergii Soreng, Finot & P. M. Peterson (todas en subg. Deschampsioidea); y T. ligulatum Finot & Zuloaga (en subg. Trisetum, sect. Trisetaera). Se presentan claves para los géneros, subgéneros, secciones y especies de Trisetum, Peyritschia y Sphenopholis presentes en México y América Central. Los nombres Trisetum gracile E. Fourn. y Trisetum subsect. Deschampsioidea Louis-Marie fueron lectotipificados.