Novos sinônimos e ocorrências em Paspalum L. (Poaceae)

Propõe-se a sinonimização de quinze nomes referentes a espécies de Paspalum, grupo informal Plicatula: P. paludosum Swallen e P. validum Swallen em P. atratum Swallen, P. guaricense Swallen em P. centrale Chase, P. plicatulum Michx. var. villosissimum Pilg. em P. geminiflorum Steud., P. goyanum Swallen e P. plicatulum var. rigidum Döll em P. glaucescens Hack., P. gracile J. Le Conte e P. nicorae Parodi em P. lepton Schult., P. limbatum Henrard, P. formosum Swallen e P. pontanale Swallen em P. lenticulare Kunth, P. olivaceum Hitchc. & Chase em P. riparium Nees, P. plicatulum var. cinereum Döll, P. macedoi Swallen e P. kempffii Killeen em P. rojasii Hack. e P. telmatum Swallen em P. wrightii Hitchc. & Chase. Relata-se pela primeira vez a ocorrência de P. lepton no estado brasileiro do Mato Grosso do Sul

Intraspecific tetraploid hybrids of Paspalum notatum: agronomic evaluation of segregating progeny

For many decades, animal production in southern Brazil has been based on native forage grasses. Paspalum notatum Flügge (bahiagrass) is one of the most frequently used native grass in southern Brazil. The native germplasm of P. notatum is tetraploid and displays apomictic reproduction; hence, chromosome doubling of sexual diploid accessions is required to facilitate hybridization. The main goal of this study was to evaluate forage production and other agronomical evaluation of P. notatum intraspecific hybrids in order to obtain new varieties that could be registered and/or protected and launched as new cultivars in the future. Three tetraploid sexual genotypes were crossed with the ecotypes Bagual and André da Rocha. Biomass production (leaf, stem, and inflorescence fractions), plant growth habit, plant height, number of tillers, and frost damage were evaluated in the resulting hybrids. The general combining ability (GCA) and specific combining ability (SCA) were calculated for the six families generated. We evaluated 196 hybrids and the most productive yielded 42 % more total dry mass than the most productive parent (ecotype Bagual), and Bagual production was seven-fold higher than that of cultivar ‘Pensacola’. The highest GCA values were observed for Bagual and Q4205. No correlation was observed between leaf coloration and the frost effect or regrowth in the following winter. Similarly, no correlation between plant growth habit and dry mass production was observed. The reproduction mode of the most productive hybrids are currently being analyzed in larger plots to identify apomictic and sexual genotypes for future registration and protection

Utilização de microssatélites e RAPD na caracterização molecular de acessos de paspalum urvillei steudel

Este estudo foi realizado com o objetivo de verificar a diversidade genética na coleção de acessos de P. urvillei do Departamento de Plantas Forrageiras e Agrometeorologia(DPFA) da Faculdade de Agronomia (UFRG) visando sua utilização em futuros trabalhos de seleção. Foram avaliados 64 acessos provenientes do Rio Grande do Sul, 1 de Xanxerê, Santa Catarina, três de Curitiba, Paraná, e 1 da Argentina. A diversidade genética foi analisada por meio de marcadores do tipo RAPD e SSR. Utilizaram-se dez primers para marcadores RAPD, o que possibilitou obter 56 bandas polimórficas e 11 grupos no dendrograma com similaridade média de 0,70. Na técnica de SSR, foram utilizados sete primers e obtidas 28 bandas polimórficas, formando sete grupos no dendrograma com similaridade média de 0,66. Ambos os marcadores foram eficientes para o agrupamento de acessos coletados. O uso de maior número de primers para gerar mais bandas polimórficas foi necessário para obtenção de fingerprints genômicos dos indivíduos similares. Os dendrogramas gerados neste estudo dão subsídios para futuros cruzamentos de gerações parentais contrastantes ou similares no melhoramento de Paspalum urvillei.The aim of this study was to estimate the genetic diversity among accesses of P. urvillei of Departamento de Plantas Forrageiras e Agrometeorologia (DPFA) of the College of Agronomy – UFRGS and to evaluate their use in selection programs. Sixty four accesses from different cities of the Southern Region of Brazil (Rio Grande do Sul, Santa Catarina and Parana States) and from Argentine were analyzed by RAPD and SSR molecular markers. Ten primers of RAPD markers were used and resulted in 56 polymorphic bands and 11 groups in a dendrogram with average similarity 0.70. Seven primers were used for the SSR technique and resulted in 28 polymorphic bands and seven groups in a dendrogram with average similarity 0.66. Both markers were efficient on grouping the accesses collected across the Southern region. A large number of primers was required to generate additional polymorphic bands to get genomic fingerprints of similar individuals. The dendrograms obtained from this study provided significant information for designing crossing strategies of parental generations in breeding programs of P. urvillei