ABSTRACT: The present study described the chemical composition and somatic cell score (SCS) of samples of refrigerated raw milk collected from commercial farms in the state of Rio Grande do Sul in order to better understand the behavior of constituents present in non-fatty solids (NFS) in milk according to the season of the year. Means were used to describe statistical data. To estimate the probability of NFS levels meeting IN 76 (BRAZIL, 2018), binary logistic regression was used. It was reported that 18.2% (233.817) of analytical results showed NFS below 8.4%, representing the minimum required by IN 76. The highest average NFS level observed in the five-year period was registered in the micro-region of Passo Fundo (8.70%) in winter. The microregion with the lowest results was Porto Alegre (8.53%); however, it still demonstrated levels within the limits established by IN 76. The study indicates that milk constituents show differences between seasons. In autumn and winter, the constituents remained equal to or higher than those required by current legislation, while spring and summer were the periods with the lowest NFS values. The SCS was also influenced by the seasons, with the highest rates in spring, summer, and autumn.

Even though oats (Avena spp.) have the capacity to produce numerous compounds with the potential to act antagonistically against plant pathogens, studies on the genotypic effect of this crop focusing on their nematicidal activity are limited. The objective of this study was to verify the effect of the aqueous extracts prepared with the biomass of oat genotypes, on the hatching of second-stage juveniles of root-knot nematodes (Meloidogyne javanica and Meloidogyne incognita). The bioassays were carried out in a completely randomized design with four replications. Eighteen extracts were evaluated, consisting of a combination of six oat genotypes Agro Quarai, Agro Esteio, Embrapa 139, AF 12202, UPFPS Farroupilha, and AF 1345 Ucraniana, and three extract concentrations (5 %, 10 %, and 20 % w/v). Three additional treatments were added to the study (distilled water, chemical nematicides abamectin, and imidacloprid + thiodicarb). The treatments and the suspension containing nematode eggs were placed in Petri dishes and incubated in a growth chamber for ten days. At the 5 % and 10 % w/v concentration levels, a genotype effect was observed in the hatching of juveniles for both nematode species. For the control of M. javanica the extracts of Embrapa 139 had a better performance, while the extracts of Agro Quarai and AF1345 Ucraniana performed better when under the control of M. incognita. Thus, oat biomass formation might have the ability to suppress the nematode population in the soil, and could therefore, be used for the management of root-knot nematodes.

A aveia-preta é uma planta de múltiplos usos no sistema agrícola, contudo programas de melhoramento tem pouco sucesso em obter novos genótipos, não se sabe o motivo exato. Assim sendo, este trabalho teve como objetivo caracterizar e avaliar a morfologia floral e a viabilidade polínica em Avena strigosa. Para isso, duas cultivares de hábito e ciclo contrastantes (IAPAR 61-Ibiporã e UPFA 21-Moreninha) foram estabelecidas no campo e em vaso no município de Passo Fundo, no norte do estado do Rio Grande do Sul. Foram realizadas avaliações morfológicas na panícula, espiguetas e grãos de pólen das cultivares. Na cv. IAPAR 61-Ibiporã foram encontrados os maiores comprimentos de espigueta, ráquila, gluma I, gluma II, pálea, arista e pistilo. Na cv. UPFA 21-Moreninha encontrou-se maior comprimento da ráquis, lema e antera apicais e maior densidade de espiguetas na panícula. Em relação à viabilidade polínica, as cultivares não diferem entre si, evidenciando-se que apenas as medidas dos grãos de pólen foram contrastantes.

Resumo Biologia floral de cultivares de Avena strigosa. A aveia-preta e uma planta de multiplos usos no sistema agricola, contudo programas de melhoramento tem pouco sucesso em obter novos genotipos, nao se sabe o motivo exato. Assim sendo, este trabalho teve como objetivo caracterizar e avaliar a morfologia floral e a viabilidade polinica em Avena strigosa. Para isso, duas cultivares de habito e ciclo contrastantes (IAPAR 61 ? Ibipora e UPFA 21 ? Moreninha) foram estabelecidas no campo e em vaso no municipio de Passo Fundo, no norte do estado do Rio Grande do Sul. Foram realizadas avaliacoes morfologicas na panicula, espiguetas e graos de polen das cultivares. Na cv. IAPAR 61 ? Ibipora foram encontrados os maiores comprimentos de espigueta, raquila, gluma I, gluma II, palea, arista e pistilo. Na cv. UPFA 21 ? Moreninha encontrou-se maior comprimento da raquis, lema e antera apicais e maior densidade de espiguetas na panicula. Em relacao a viabilidade polinica, as cultivares nao diferem entre si, evidenciando-se que apenas as medidas dos graos de polen foram contrastantes. Palavras-chave: Aveia-preta; Morfologia; Viabilidade polinica Abstract Black oat is a plant of multiple uses in the agricultural system, however, without knowing exactly why, breeding programs have had little success in obtaining new genotypes. The goal of this study was to characterize floral morphology and evaluate if there is variability in Avena strigosa in its pollen viability. Thus, two cultivars of contrasting habits and cycles (IAPAR 61 ? Ibipora and UPFA 21 ? Moreninha) were cultivated in a field and in a vase in the city of Passo Fundo, in the north of the state of Rio Grande do Sul, Brazil. Morphological evaluations were performed on the panicle, spikelets and pollen grains of the cultivars. The largest lengths of spikelet, rachilla, glumes I, glumes II, palea, ridge and pistil were found. in cv. IAPAR 61 ? Ibipora. Larger length of the rachis, lemma and floret in the apical and greater density of spikelets in the panicle were found in cv. UPFA 21 ? Moreninha. As for pollen viability, the cultivars do not differ from each other, evidencing that only pollen grain measurements were contrasting. Key words: Black oat; Morphology; Pollen viability

The runout of newly cultivated areas in the world without recurring to the deforestation, demand a necessity to improve yield to sustain a growth population which demands each time more food. To avoid that is necessary to solve the main issues which cause crop productivity reduction, such as lodging which causes yield reduction in many major crops such as wheat, barley, rice and oat. In this sense, a study with eight cultivars evaluated morphological traits of the stem as crown diameter, internal and external diameter of the first four basal internodes, the length of internodes, peduncle and panicle, plant height, and also lodging resistance factor (cLr), green and dry panicle matter. The diameter of the crown does not show differences among the cultivars, the morphological characters which showed correlation and relative contribution with cLr were the internal and external internodes diameters, showing their capacity to be one of morphological traits of the stem to an indirect selection of resistance to lodging in Avena sativa L. The length did not show a good correlation with lodging, probably due to the fact that this trait was the focus of breeders for many years, reaching the plateau, demanding focus in other traits to avoid lodging such as interna and external diameter of internodes. The cultivar URS Brava and IPR Afrodite demonstrated to be a source of lodging resistance in oat.

The objective of this study was to evaluate the resistance reaction of Avena spp. after inoculation of different concentrations of eggs and juveniles of M. javanica and M. incognita. Ten oat genotypes (Avena sativa: UPFPS Farroupilha, UPFA Ouro, IPR Afrodite, AF1345 Ucraniana; A. strigosa: Agro Quaraí, Agro Esteio, Embrapa 139, Iapar 61 Ibiporã, UPFA 21 Moreninha, AF 12202) were evaluated in bioassays for resistance against the root-knot nematodes, Meloidogyne javanica and M. incognita. Susceptible (Solanum lycopersicum and Glycine max) and resistant (Crotalaria spectabilis) species were used as control treatments. Depending on the inoculum level, the oats showed a different response to nematodes. All genotypes of oats were resistant to M. javanica when a high inoculum level (5,000 eggs and J2 per plant) was used but under low inoculum level (1,500 eggs and J2 per plant), AF 12202, Iapar 61 Ibiporã, Agro Esteio and Agro Quaraí were susceptible. All genotypes of oats were resistant to the inoculation of 2,900 eggs and J2 of M. incognita, except for ‘Iapar 61’ that showed susceptibility in this concentration. At lower inoculum level (1,500 eggs and J2) Agro Quaraí, Agro Esteio and Iapar 61 Ibiporã were susceptible. The reaction of oats to M. javanica and M. incognita depends on the inoculum level. The resistance reaction at low inoculum density of A. sativa ‘AF 1345 Ucraniana’ and ‘IPR Afrodite’ allows its use in breeding programs in oats and suggests the possibility of management tool in areas infested with both root-knot nematode species.

ABSTRACT: In view of the rapid evolution of Conyza sumatrensis populations resistant to glyphosate, it is necessary to understand the genetic diversity aimed to improve strategies for managing this weed. We investigated the genetic dissimilarity among 15 biotypes of C. sumatrensis from different geographic regions using microsatellite loci. The biotypes, were cultivated in a greenhouse to obtain vegetal material for DNA extraction. Nineteen microsatellite markers (SSR), were developed for C. sumatrensis biotypes. The genetic dissimilarity was estimated by the Jaccard coefficient (JC) and the biotypes grouped by the UPGMA method. The results demonstrated a high dissimilarity (JC = 7.14 to 82.62) of the analyzed material, with the biotypes forming five groups, being one group formed just by the susceptible biotype and in the others grouped by biotypes from distinct locations in the same group The high genetic diversity of C. sumatrensis indicates that the biotypes may show different responses to different management strategies, and that the mechanisms of resistance to herbicides and characteristics of evolution of populations due to adaptability may be some of the factors involved in the genetic variability of the species.

Eragrostis plana (Nees) is an allelopathic plant with invasive potential in South American pastures. To isolate and identify phytotoxic compounds from leaves and roots of E. plana, a bioassay-directed isolation of the bioactive constituents was performed. This is the first report on a new diterpene carbon skeleton, neocassane, and of three new neocassane diterpenes, neocassa-1,12(13),15-triene-3,14-dione, 1; 19-norneocassa-1,12(13),15-triene-3,14-dione, 2; and 14-hydroxyneocassa-1,12(17),15-triene-3-one, 3, identified from the roots. Compounds 1, 2, and 3 inhibited the growth of duckweed by 50% at concentrations of 109 ± 28, 200 ± 37, and 59 ± 15 μM, respectively. Compound 2 was fungicidal to Colletotrichum fragariae, Colletotrichum acutatum, and Colletotrichum gloeosporioides. The compounds identified here could explain the allelopathy of E. plana. The description of the newly discovered compounds, besides contributing to the chemical characterization of the species, may be the first step in the study of the potential of these compounds as bioherbicides.

ABSTRACT: The phenological stage, post-harvest processing and quantity of material can interfere in the allelopathic activity of extracts. The objective of this study is to test the allelopathic effect of aqueous extracts of the leaves of Annoni grass (Eragrostis plana), an invader of natural pastures. Twelve extracts were prepared by combining the phenological stage of the plants when harvesting the leaves (vegetative; flowering), post-harvest processing before extraction (fresh; dry at 40 oC), and the amount of plant material (5, 15, and 25 g 100 mL-1 distilled water). Two bioassays were conducted in a germination chamber, with evaluation of germination and growth of seedlings of lettuce (Lactuca sativa) and white clover (Trifolium repens). The extracts with higher allelopathic activity were further developed with 15 and 25 g of dried leaves and harvested in plants at the vegetative stage. Germination was attributed to being the greatest contribution to the divergence between the extracts. White clover was more sensitive to extracts, for which 50% to 67% of the extracts were effectively allelopathic (≥50% inhibition); in lettuce, between 8% and 58% of the extracts exhibited this potential. The phenological stage was the factor with a greater individual effect on the allelopathic activity on lettuce and white clover seedlings, and on lettuce germination. The post-harvest processing responded by the greater variation on germination and germination speed index of white clover. The sensitivity of the white clover to extracts of Annoni grass suggests a compromise of its establishment in pastures with the presence of the invader.

The structure of arbuscular mycorrhizal fungi (AMF) communities in areas under strawberry cultivation in the Brazilian subtropics has been poorly studied. Thus, we characterized cultivated and native forest soils, of reference-sites in strawberry cultivation in southern Brazil, regarding the AMF community and investigate if there is variability in the diversity in the mycorrhizal communities of these soils. For this, we evaluated eight soils, in a completely randomized design experiment. We observed that the species Claroideoglomus aff. luteum, Claroideoglomus claroideum, C. etunicatum, Funneliformis mosseae and Glomus sp2 were the most frequent. Native forest soils had more fungal species than cultivated soils. Soils little anthropized under strawberry cultivation resembled the natural soils regarding the AMF heterogeneity. We conclude that there are AMF diversity in soils of reference-sites in strawberry cultivation, and that C. claroideum and C. etunicatum are generalist, independent of the ecosystem. This study contributes significantly to our knowledge about the community composition of AMF in soils of reference-sites in the strawberry cultivation in the Brazilian subtropics. Thus, it becomes possible the development of inoculants for this horticultural crop, with the role of making their cultivation more sustainable.

The concentration of catechin, epicatechin, rutin and quercetin was determined by high performance liquid chromatography on methanolic extracts from leaves+stems and flowers+fruits of Lotus corniculatus harvested at vegetative and reproductive stages. Phenological stage did not affect the flavonoid concentration of leaves+stems extracts, which presented higher concentration of catechin (2.11 mg.g-1) than flowers+fruits extract (1.18 mg.g-1). The highest concentrations of epicatechin (11,6 mg.g-1), quercetin (1,26 mg.g-1) and rutin (2,23 mg.g-1) occurred in the flower+ fruit extract. The concentration of phenolics in this species seems to be dependent on the biomass allocation in the vegetative and reproductive organs of the plants.

Allelopathy is an important ecological mechanism in natural and managed ecosystems. Its study is critical to understand natural plant behaviors, to isolate allelochemicals with herbicide potential, and to use the allelopathic genes in transgenic studies. Poaceae is an ecologically dominant plant family and it is economically important worldwide because its chemical diversity represents an important source to discover new molecules. From this viewpoint, Brazil is an interesting place to study, encompassing 197 genera of the Poaceae family, many of them being dominant in various biomes and some being native to Brazil. Here, we review the literature describing allelopathic activities involving grasses of the Poaceae family. We evaluate the experimental conditions used in these studies, we identify the allelochemicals involved, and, finally, we assess the applicability of allelopathy. Our main findings are (1) among the 47 Brazilian species studied for their allelopathic effects, only Bothriochloa barbinodis, Bothriochloa laguroides, Paspalum notatum, and Paspalum urvillei are native to Brazil; (2) 51% of the reviewed studies prepared extracts from the leaves and used lettuce as the target plant; and (3) 64% of the papers identified allelochemicals, of which 67% were phenolic acids. This first bibliographical survey on allelopathy in Poaceae species present in Brazil shows that less than 3% of the Brazilian species have been studied, suggesting it is an incipient research subject. Since this plant family is a valuable source of unknown natural products, refining such studies should contribute to a better understanding of the ecosystem relationships. Identification and isolation of grass allelochemicals should promote environmentally safer compounds with bioherbicide properties, in sustainable agriculture.

The objective of this work was to evaluate eleven oat (Avena spp.) cultivars for the reaction to the blast caused by the fungus Pyricularia oryzae Cav., under controlled conditions, to identify promising cultivars for use in genetic breeding programs. Five cultivars of Avena sativa, four of A. strigosa and two of A. brevis were tested. The reaction was observed in leaves, with four isolates of P. oryzae, in the concentration of 2 x 105 conidia/ml. It was quantified the number and expansion of lesions, severity and area under the curve of disease progression. The cultivars presented variability regarding the reaction to inoculation. The best performance was A. sativa 'URS Taura', which showed the lowest values for number of lesions (2/leaf), length (5.42 mm) and width (1.25 mm) of lesions, area under the curve of disease progression (0.65) and severity (6%). No genotype was resistant, but four cultivars showed severity percentages compatible with 'Moderately resistance': A. sativa 'URS Taura' (6%), 'UPFA Ouro' (14%) and 'IPR Afrodite' and A. brevis 'BRS Madrugada' (24%). These genotypes are references for use as parents in oat breeding programs.

Morphological and phenological characters are used in the selection, breeding, and description of plant varieties with varying genotypes. The stability of these descriptors in the face of environmental changes can determine their usefulness in situations where plant varieties must be reliably identified. The objective of this study was to verify the expression of morphological and phenological descriptors and use them to distinguish between white oat cultivars (Avena sativa L.) in two growing periods. For this, five cultivars, protected and belonging to four breeders, referred to as G1, G2, G3, G4, and G5, were sown in the typical growing season in southern Brazil (autumn-winter) and outside that period (winter-spring), and grown for forty days. The experiment was established in the field, in a randomized block design replicated three times. The cultivars were evaluated for 42 descriptors (15 quantitative and 27 qualitative). Quantitative data were analyzed by analysis of variance, the comparison of averages, and multivariate analysis by generating average euclidean distances. Qualitative data were analyzed by mode determination, followed by obtaining the similarity index. The relationship between cultivars was illustrated by dendrograms. The stability index for each descriptor was calculated. A genotype x environment interaction was observed for 28 descriptors. The stability of descriptor appearance and persistence over the growing season was higher in qualitative (44%) than in quantitative (7%) descriptors. The most stable qualitative descriptors were lemma color, hairiness of the upper node, flag leaf position, hairiness of the base of the grain, basal grain length, and rachilla length. The most stable quantitative descriptor was flag leaf length. Shifting the white oat growing season from autumn-winter to winter-spring reduced the cycle and modified the expression of most descriptors by changing the phenotypic distinctness between cultivars.

The Paspalum genus includes several species that are important for livestock in Rio Grande do Sul, such as P. notatum and P. guenoarum, typical of native pastures of the Pampa biome. The aim of this study was to investigate forage production and chemical composition of four ecotypes of these species in relation to the cv. 'Pensacola' (P. notatum). Ecotypes of P. guenoarum (Azulão and Baio) and P. notatum (André da Rocha and Bagual) and the cv. 'Pensacola' were evaluated for two years, during which four cuts/year were made. The work was carried out under field conditions at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul (30°05'S; 51°39'W), in a completely randomized design. P. guenoarum stood out for higher productivity and greater tolerance to cold; the Azulão ecotype showed more autumn production in relation to the other ecotypes. Crude protein content ranged from 14 (Baio) to 15% ('Pensacola'); for neutral detergent fiber, the variation was 68 (Azulão) to 71% ('Pensacola') and for acid detergent fiber there was a variation of 38 ('Pensacola') to 43% (Baio). The data demonstrates the potential of native genotypes for use as cattle feeding in southern Brazil.

Caracteres morfológicos e fenológicos são utilizados na seleção, cruzamentos e descrição de genótipos, sua instabilidade frente a alterações ambientais pode determinar o seu valor na etapa de proteção de cultivares. Este trabalho foi desenvolvido com o objetivo de verificar a expressão de descritores morfológicos e fenológicos e, consequentemente, a dissimilaridade entre cultivares de aveia-branca (Avena sativa L.) em dois períodos de cultivo. Para isso, cinco cultivares, protegidas e oriundas de quatro obtentores e, aqui, codificadas (G1, G2, G3, G4 e G5), foram semeadas dentro do período recomendado para a cultura no sul do do Brasil (outono-hibernal) e fora desse período (hiberno-primaveril), com intervalo de quarenta dias. O experimento foi estabelecido em campo, em blocos casualizados, com três repetições. As cultivares foram avaliadas quanto a 42 descritores (15 quantitativos e 27 qualitativos). Os dados quantitativos foram submetidos à análise de variância, seguida da comparação de médias, e à análise multivariada, por meio da geração da distância euclidiana média. Os dados qualitativos foram submetidos à determinação da moda, seguida da obtenção do índice de similaridade. A relação entre as cultivares foi ilustrada por meio de dendrogramas. Foi calculado o índice de estabilidade dos descritores. A interação genótipo x ambiente foi observada em 28 descritores. A estabilidade de expressão, à alteração no período de cultivo, foi maior nos descritores qualitativos (44%), quando comparada aos quantitativos (7%). Os descritores qualitativos mais estáveis foram: cor do lema, pilosidade do nó superior, posição da folha-bandeira, pilosidade da base do grão, comprimento dos pelos basais do grão e comprimento da ráquila. O descritor quantitativo mais estável foi o comprimento da folha-bandeira. O atraso no período de cultivo da aveia-branca, de outono-hibernal para hiberno-primaveril, reduz o ciclo da cultura e modifica a expressão da maioria dos descritores, alterando a dissimilaridade fenotípica entre cultivares.