Transference of natural diversity from the apomictic germplasm of Paspalum notatum to a sexual synthetic population

Genetic improvement in apomictic forage species has been restricted because of the absence of genetic variability in sexual germplasm with the same ploidy level. Following a new breeding scheme, a sexual synthetic tetraploid population (SSTP) of Paspalum notatum has been generated. The objectives of this work were: (a) to evaluate the genetic variability in SSTP by means of molecular markers, morphologic and agronomic traits, and seed fertility and quality traits and (b) to assess the transference of genetic variability from the apomictic germplasm to the sexual one. Molecular markers revealed a twofold higher level of variability in the SSTP in comparison with the sexual germplasm utilised for its generation, and similar levels with the apomictic ones; moreover, markers showed that most of the variability was inherited from theapomictic germplasm. Morphologic and agronomic traits and seed fertility and quality traits showed high levels of variation in the three groups of genotypes indicating that the new breeding scheme was effective in transferring variability from the apomictic germplasm to the SSTP. This new population will be useful in breeding of P. notatum, and the breeding scheme used for its generation may be used in other apomictic species.Fil: Zilli, Alex Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Acuña, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Schulz, Roberto R.. Universidad Nacional del Nordeste; ArgentinaFil: Marcón, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Brugnoli, Elsa Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Novo, Sabina F.. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; ArgentinaFil: Quarin, Camilo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Martínez, Eric Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

Suscetibilidade de biótipos de arroz-vermelho e de cultivares de arroz irrigado ao herbicida imazethapyr Susceptibility of red rice biotypes and commercial rice cultivars to imazethapyr

Para avaliar a suscetibilidade de biótipos de arroz-vermelho(Oryza sativa) e cultivares comerciais de arroz ao herbicida imazethapyr, realizou-se um ensaio em casa de vegetação com cinco biótipos de arroz-vermelho (acessos Santa Maria 5, Pelotas 3, Rio Pardo 1, Manoel Viana 2 e Catuçaba 1), dois cultivares comerciais de arroz: Clearfield® (IRGA 422 CL e Puitá INTA CL) e um cultivar convencional (IRGA 417). Utilizou-se a metodologia de curvas de dose-resposta proposta por Seefeldt et al. (1995). A metodologia de curvas de resposta foi gerada a partir dos parâmetros do modelo logístico e dos valores de I50. Os biótipos de arroz-vermelho e os cultivares foram submetidos a seis doses do herbicida imazethapyr (0; 33,12; 66,25; 132,5; 265,0; e 530,0 g i.a. ha-1). As plantas de arroz foram contadas e coletadas no 20º dia após a aplicação dos tratamentos. A análise do percentual de dano foi realizada através de avaliação visual da fitointoxicação (%), massa verde e massa seca das plantas. Analisando as curvas e os resultados da análise da variância, pode-se inferir que os cultivares Clearfield Irga 422 CL e Puitá INTA CL foram significativamente iguais ao biótipo de arroz-vermelho Catuçaba 1, resistindo a doses de imazethapyr superiores à recomendada em campo para o sistema Clearfield®. Os biótipos Manoel Viana 2, Santa Maria 5 e Pelotas 3 agruparam-se com o cultivar convencional IRGA 417, sendo suscetíveis à dose comercial do herbicida. O biótipo Rio Pardo 1 também é resistente ao herbicida imazethapyr, porém menos resistente que o biótipo Catuçaba 1.<br>To evaluate the susceptibility of biotypes of red rice (Oryza sativa) and commercial rice cultivars to the herbicide imazethapyr, a greenhouse assay was conducted with five red rice biotypes (accesses Santa Maria 5, Pelotas 3, Rio Pardo 1, 2 and Manoel Viana Catuçaba 1), two commercial rice cultivars: Clearfield ® (Irga CL 422 and CL Puit INTA), and a conventional cultivar (Irga 417). The methodology of dose-response curves proposed by Seefeldt et al. (1995) was applied. The methodology of response curves was generated from the parameters of the logistic model and the values of I50. The red rice biotypes and cultivars were subjected to six doses of the herbicide imazethapyr (0, 33.12, 66.25, 132.5, 265.0 and 530.0 g a.i. ha-1). Rice plants were counted and collected on the 20th day after treatment application. Damage percentage analysis was performed by visual assessment of phytotoxicity (%), plant green mass, and plant dry mass. Through the curves and results of the analysis of variance, it could be inferred that the cultivars Irga Clearfield CL 422 and CL Puit INTA were significantly equal to red rice biotype Catuçaba 1, resisting to imazethapyr doses higher than those recommended to the Match Clearfield ® system in the field. Biotypes Manoel Viana 2, Santa Maria 5, and Pelotas 3 grouped with the conventional cultivar IRGA 417, and were susceptible to the commercial dose of the herbicide. Rio Pardo 1 biotype is also resistant to the herbicide imazethapyr, but less than biotype Catuçaba 1

Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda Crescimento das espécies de capim-colchão Digitaria ciliaris e Digitaria nuda

The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.<br>O objetivo da presente pesquisa foi comparar o crescimento das espécies de capim colchão D. ciliaris e D. nuda, em condições não-competitivas. Para isso, foram conduzidos dois experimentos, um de março a julho de 2010 e outro de fevereiro a junho de 2011. O delineamento experimental de ambos os ensaios foi inteiramente casualizado, perfazendo um esquema fatorial (2 épocas x 2 espécies de capim colchão x 12 períodos de avaliação), com quatro repetições. As avaliações iniciaram-se aos 15 dias após a semeadura (DAS), e repetidas semanalmente até os 92 DAS. As variáveis avaliadas foram massa seca total (raízes+folhas+colmos), área foliar, número de folhas e de perfilho. Os resultados foram submetidos a análise de variância e com as médias foram calculadas a taxa de crescimento absoluto, taxa de crescimento relativo e a razão de área foliar, as quais foram ajustadas a modelos de regressão. As espécies de capim-colchão diferiram entre si quanto a área foliar, numero de folhas, número de perfilho e matéria seca por planta. D. ciliaris para todas as variáveis obteve média estatisticamente superior em relação a D. nuda. Em relação à velocidade com que o crescimento das espécies ocorreu, a taxa de crescimento absoluto e relativo de D. ciliaris também foi superior a D. nuda. Além disso, D. ciliaris também teve menor razão de área foliar indicando maior eficiência na conversão de energia luminosa em carboidratos. Pode-se concluir que D. ciliaris apresentar maior crescimento, em condições onde não há limitações de nutrientes e disponibilidade hídrica, em relação a D. nuda principalmente por apresentar maior área foliar, numero de folhas e acúmulo de matéria seca por planta

Leaf surface characters applied to lauraceae taxonomy in a seasonal forest of southern Brazil

The goal of this work was to test if the macro and micro morphological analysis of the leaf surface could provide vegetative diagnostic characters for some of the most common Lauraceae species in Southern Brazilian Seasonal Forests. The leaf printing technique with universal instantaneous adhesive was used for the epidermical microscopical analysis and external macroscospical analyses of leave were made. Microscopic evaluation revealed the visibility and contours of anticlinal walls of epidermical cell and stomata and shape of guard-cells. Macroscopic evaluation showed the absence or presence of characters such as hairiness, domatia and scents. The results showed that analyzed characters, together with other diagnostic characteristics, could contribute in taxonomic delimitation of some common Lauraceae species in the Southern Brazil

Contagens cromossômicas em espécies brasileiras de Paspalum L. (Gramineae) Chromosome counts in brazilian species of Paspalum L. (Gramineae)

A partir de coletas de germoplasma de espécies de Paspalum, realizadas nas cinco regiões do Brasil, e subseqüentes análises citológicas em mitose ou meiose, reportam-se os números de cromossomos de 107 acessos, distribuídos por 33 espécies, representativas de 13 dos grupos taxonómicos informais em que o gênero é tradicionalmente subdividido. No grupo Plicatula, sob intensa revisão taxonómica, 27 acessos são citados ainda sem identificação específica. A região sul é muito bem representada, com 65 acessos, seguida pela região centro-oeste, com 33. Os números cromossômicos de P filifolium (2n = 20), P hartwegianum (2n = 60), P. rhodopedum (2n = 40) e P wettsteinii (2n = 40 e 60) são relatados pela primeira vez. Também são novas as contagens de 2n = 50 para P. plenum e para uma forma de P dílatatum com anteras amarelas. Encontrou-se um novo acesso diplóide (2n = 20) de P pllcatulum e mais um acesso de P mandiocanum com 2n = 50, que discrepa do nível hexaplóide, mais freqüente na espécie. Outras contagens confirmam os números já conhecidos, estendendo sua representatividade geográfica.<br>Germplasm accessions obtained in collecting missions covering all the five regions of Brazil were submitted to cytological analysis, either in mitosis or meiosis. Chromosome numbers are reported from 107 accessions of 33 species, representative of 13 of the informal taxonomic groups, in which the genus is traditionally divided. In the Plicatula group, under intensive taxonomic investigation, 27 accessions are mentioned without any specific identification. The Southern region is very well represented, with 65 accessions, followed by the West Central region, with 33. The chromosome numbers of P. fillfolium (2n = 20), P hartwegianum (2n = 60), P. rhodopedum (2n = 40) and P. wettsteinii (2n - 40 and 60) are reported for the first time. Also new are the reports of 2n = 50 for P. plenum and for a yellow-anthered form of P dilatatum. The new findings include an additional diploid accession of P plicatulum (2n = 20) and a second accession of P. mandiocanum with 2n = 50, a number in disagreement with the most frequent hexaploid level in this species. Additional data confirm previous counts, thus extending their geographic amplitude

Growing knowledge: an overview of Seed Plant diversity in Brazil

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora