Abstract Paspalum notatum is a polymorphic species with two accepted varieties, according to the ploidy level. The ploidy level is closely related to the reproductive mode of this species. Usually, diploid cytotypes have sexual reproduction, and tetraploid cytotypes have an apomictic reproduction. Apomixis limits genetic recombination, hindering the development of new cultivars. The identification of sexual plants represents many possibilities in breeding programs. This study aimed to analyze the chromosome number in P. notatum accessions under agronomic evaluation. Ploidy level was determined in 25 accessions. Two ploidy levels were detected, resulting in 21 tetraploid and four diploid accessions. The four diploid accessions originate from Argentina and Uruguay, in a region close to the origin of Pensacola, which is a diploid sexual cultivar of P. notatum. These new diploid accessions may be useful in the development of breeding programs of Paspalum species.

Abstract Evolutionary analyses have been widely used for evaluation of genetic diversity of natural populations and correlate these data to the fitness of the species, especially in the case of threatened species. Calydorea crocoides occurs in a restricted area at altitudes from 800 to 1500 m in southern Brazil and is considered endangered. A study assessing genetic diversity, cytogenetic features and ecological niche was performed aiming to characterize C. crocoides by multidisciplinary approaches. Molecular data highlighted that most of the total variation (76%; p < 0.001) was found within populations and the parameters of genetic diversity were high at the species level (PPB = 98.97%; I = 0.4319; h = 0.2821). Gene flow (Nm) was estimated in 0.97 individuals per generation. Cytogenetically, C. crocoides presents a bimodal karyotype and low asymmetry. DAPI banding pattern was uniform, but the CMA-signal evidenced a pericentric inversion in the population ESC688. The species presents high pollen viability and two different morphologies of pollen grains. Our data showed high levels of polymorphism maintained in this species that could ensure conservationist practices in which the main goal is to preserve the evolutionary potential of the species through the maintenance of genetic diversity.

ABSTRACT The objective of this study was to assess the genetic diversity among accessions of Paspalum notatum based on morphological marker traits and identify those morphological traits that contribute most to the variability among accessions. Fifty-three accessions were evaluated for the following traits: length, width, color, and pubescence of sheath; length, width, insertion angle, color of midrib, and pubescence of leaves; number, length, and angle of racemes; length of flowering stems; and plant growth habit (erect or prostrate). Multivariate analysis of the quantitative morphological data based on the Mahalanobis distance and UPGMA method grouped the accessions into 19 heterogeneous clusters. The relative contribution of each trait to cluster formation was obtained using the Singh method. Qualitative morphological traits were used to construct a dendrogram based on Jaccard's similarity, generating 13 clusters. Based on the morphological traits investigated, there is high genetic variation among accessions of P. notatum, demonstrating that these accessions have a good potential for a breeding program. Length of racemes, width of sheath, length of flowering stems, and length of leaves were found to contribute most to the variability among accessions. A number of traits contributed to a lesser degree. The set of characters used are representative of the vast phenotypic plasticity observed in P. notatum, a diversity which is likely to be related to the species apomictic form of reproduction and the origin of the accessions.

A espécie medicinal Solidago micrglossa DC., a qual é nativa da América do Sul, é usada como infusão (chá) para desordens estomacais na medicina popular. O objetivo desse estudo foi avaliar o potencial efeito citotóxico dessas infusões no ciclo celular de Allium cepa. Folhas in natura de três populações dessa espécie foram utilizadas no preparo das infusões em duas concentrações: 1,75 mg/mL e 14 mg/mL. Células de raízes de cebola (Allium cepa) foram usadas como sistema teste nos ensaios in vivo. As lâminas foram feitas através da técnica de esmagamento. As células foram analisadas em todos os ciclos celulares de A. cepa, totalizando 6000 células para cada grupo de bulbos. O índice mitótico (IM) foi calculado e a análise estatística foi realizada através do teste Qui-quadrado (χ2 = 0,05). Os resultados mostraram que as infusões de S. microglossa na maior concentração (14 mg/mL) causou uma redução no IM comparado com os controles nas populações estudadas. Nas concentrações comumente usadas pelas pessoas houve um aumento significativo do IM em relação ao controle nas populações 1 e 3 e foi reduzido na população 2. Em conclusão, infusões de S. microglossa apresentam efeito antiproliferativo na maior concentração testada.

The medicinal specie Solidago microglossa DC., which is native from South America, is used as infusion (tea) for stomach disorders in popular medicine. This study aimed to evaluate the potential cytotoxic effect of these infusions on the cell cycle of Allium cepa. In natura leaves of three populations of this species were used in preparing infusions at two concentrations: 1.75 mg/mL and 14 mg/mL. Onion (Allium cepa) root-tip cells were used as test system in in vivo assays. Slides were done through smashing technique. Cells were analyzed in all cell cycles of A. cepa, totalizing 6000 cells for each group of bulbs. The mitotic index (MI) was calculated, and the statistical analysis was carried out through the Chi-square test (χ2 = 0.05). The results show that the infusions of S. microglossa at a highest concentration (14 mg/mL) caused a significant reduction in the MI compared with control in the studied populations. In concentrations commonly used by people there was a significant increase of MI in relation to controlled populations 1 and 3 and a decrease in population 2. In conclusion, infusions of S. microglossa presented antiproliferative effect at a highest concentration.