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Recent efforts placed on breeding Paspalum species made available novel genetic resources for livestock production systems. Nitrogen (N) is an important factor to increase warm‐season grass nutritive value and production, either as anthropogenic supply or in mixture with legumes. Dry matter yield (DMY) and nutritive value in Paspalum plicatulum Michx. × Paspalum guenoarum Arechav. hybrids in response to different rates of N or in mixture with temperate legumes were evaluated for two years. The experiment was a randomized complete block design in split‐plot arrangement with three replications. Treatments were six N supply systems: 0, 60, 120, 240, 480 kg N/ha and grass–legume mixture [white clover (Trifolium repens L.) + birdsfoot trefoil (Lotus corniculatus L.)] as whole plots, and six genotypes (hybrids: 1020133, 102069, 103084, 103061, P. guenoarum ecotype ‘Azulao’ and Megathyrsus maximus cv. ‘Aruana’ used as controls) as subplots. Higher N rates increased DMY and provided variability among genotypes. In general, grass–legume mixture showed greater crude protein and digestibility, and lower neutral and acid detergent fiber than N fertilized grass (p

Foi estudado o desempenho de bezerras de corte em pastagem de azevem (Lolium multiflorum Lam.), com animais exclusivamente em pastejo ou recebendo farelo de arroz integral (FAI) em nivel de 0,8% do peso corporal associado ou nao a monensina. O FAI foi ministrado diariamente as 14 horas, e a monensina foi fornecida na quantidade de 200mg por animal. O metodo de pastejo foi continuo com numero variavel de animais. O delineamento experimental foi o inteiramente casualizado, com medidas repetidas no tempo, com tres tratamentos e tres repeticoes de area. As bezerras de corte foram submetidas a valores medios de massa de forragem (1490,0134,9kg ha-1 MS) e altura do dossel (100,68cm). As bezerras que receberam FAI independente do uso da monensina, apresentaram maior ganho diario, peso corporal, escore de condicao corporal e relacao peso corporal:altura. Em 112 dias de pastejo, as bezerras que receberam FAI com ou sem ionoforo, ganharam 28% do peso corporal em relacao ao peso adulto projetado. O uso de FAI associado ou nao a monensina nao expressou alteracao na area pelvica das bezerras, na taxa de lotacao e no ganho de peso por area.%%%%The productive and reproductive performance of beef heifers grazing Italian ryegrass (Lolium multiflorum Lam) were studied with animals exclusively on pasture or receiving 0.8% of body weight of rice bran plus monensin or not. The rice bran was given daily at 2 pm and the monensin was provided in the amount of 200mg per animal. The grazing method was continuous with variable number of animals. The experimental design was completely randomized with repeated measures on time, three treatments and three area replicates. The beef heifers were submitted to average values of forage mass (1490.0134.9kg ha-1 MS) and sward height (100.68cm). Beef heifers supplemented with rice bran plus monensin or not had higher daily gain, weight body, body condition score and body weight:height ratio. Beef heifers receiving rice bran with or without ionophore in 112 days of grazing gain 28% of body weight in relation to adult weight. The supplementation with rice bran to grazing animals no change in pelvic area, stocking rate and area weight gain.

The rational use of N fertilization is essential to increase the recovery efficiency and crop productivity and decrease the cost of production. The objective of this study was to assess forage yield (TDM), tillers population density (TPD) and N use efficiency (NUE) in six Paspalum notatum Flüggé genotypes in response to N fertilization. The experimental design involved randomized blocks on a subdivided plot design. In 2014-2015 the TDM was higher for the C22 and B26 hybrids (P < 0.0001), which were similar to each other, with an average of 6173 kg DM ha-1 yr-1. In 2015-2016 the TDM of the genotypes ranging from 7053 to 13773 kg DM ha-1 yr-1, for pastures fertilized with 0 and 480 kg N ha-1 yr-1, respectively. An interaction was found between Genotype × N fertilization level (P = 0.0155) for TDM in 2016-2017. In the years 2015-2016 and 2016-2017 the C22 hybrid standed out as the genotype with the highest tiller production in response to N fertilization. In the year 2014-2015 NUE was higher (P = 0.0015) in the N fertilization levels N60, being of 15.5 kg DM kg-1 N. In the years 2015-2016 and 2016-2017 the NUE was higher at fertilization level N120 (P < 0.05), being of 21.1 and 31.5 kg DM kg-1 N, respectively. The C22 hybrid was distinct as the genotype with the highest DM yield and superior tillering characteristics. The N fertilization level of 120 kg N ha-1 yr-1 promoted greater NUE in all P. notatum genotypes

This study aimed to estimate the genetic parameters, genetic correlations, genetic dissimilarity, and predicted gains with the selection of interspecific apomictic Paspalum plicatulum × Paspalum guenoarum hybrids in relation to seed yield traits. Nineteen genotypes that showed increased forage yield in previous studies were planted in a randomized complete block design with ten blocks. Traits evaluated in this study were: number of tillers/plant, number of reproductive tillers/plant, number of racemes/inflorescence, number of seeds/inflorescence, weight of a thousand seeds, and seed yield. Data were analyzed using a mixed model approach. The genotypes evaluated in our study showed improvement potential in relation to high heritability (H a 2 > 0.50 ), high precision (Acgen> 90%), and genetic dissimilarity (forming three groups) for seed yield traits. Seed yield showed high correlation to reproductive tillers that can be used as indirect selection tools for genetic improvement of seed yield.

The objective of this study was to determine the leaf tissue flows in Italian ryegrass (Lolium multiflorum Lam.), in different phenological stages, grazed by lambs, and managed under three herbage allowances (6, 9 and 12 kg DM/100 kg body weight under rotational stocking method. The experimental design was completely randomized, with repeated measures arrangement. Forage allowances determined similar growth and intake flows, actual and potential utilization efficiencies of grass and they were different in the phenological stages of Italian ryegrass. The intake of leaf blade, as a percentage of body weight, was higher in the 12% herbage allowance. Considering leaf tissue flows, Italian ryegrass can be managed in forage allowances that vary between 6 and 12 kg DM/100 kg body weight. RESUMO: Este trabalho foi conduzido com o objetivo de determinar os fluxos de tecidos foliares em diferentes estádios fenológicos do azevém (Lolium multiflorum Lam.), pastejado por cordeiras, manejado sob três níveis de oferta de forragem (6; 9 e 12 kg de MS/100 kg de peso corporal), sob lotação intermitente. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo. Os fluxos de crescimento e consumo de lâminas foliares, as eficiências real e potencial de utilização do pasto foram similares nas ofertas de forragem e diferentes nos estádios fenológicos do azevém. O consumo de lâminas foliares em porcentagem do peso corporal foi superior na oferta de forragem 12%. Considerando os fluxos de tecidos foliares, o azevém pode ser manejado com ofertas de forragem que variam entre 6 a 12 kg de MS/100 kg de peso corporal.

The aim of this study was to estimate the genetic parameters and predicted gains with selection of interspecific hybrids of Paspalum in relation to seed production traits Data were analyzed in randomized block design, with 23 genotypes arranged into ten blocks, according to the methodology of mixed models by the REML/BLUP procedure. The traits considered in the study were: number of total tillers/plant, number of reproductive tillers/plant, number of racemes/inflorescence, number of seeds/inflorescence, weight of a thousand seeds and seed production. Variability among genotypes, high heritability (>0.50), except total tillers (0.44) and number of racemes (0.36), and high accuracy (>0.90) were identified for all traits. The hybrids 10E5052, 10E4026, 10E507, 10E4025 and 10E40104 are among the top ten because they have high genetic values in three or more traits, indicating that these genotypes should be recommended for direct use in planting or potential parents to be used in new crosses.

The use of genetic divergence as a basis for identifying superior individuals, with greater heterozygosity, is important in view of the difficulty when selecting of dissimilar genotypes exhibiting high average for interest traits. The aim of this study was to evaluate the genetic divergence and the expression of seed production traits in seventeen apomictic Paspalum plicatulum × Paspalum guenoarum hybrids and two male parents (P. guenoarum). A randomized block design was used, with genotypes individually arranged into ten blocks. The following traits were assessed: total number of tillers/plant (TT), reproductive tiller/plant (RT), number of racemes per inflorescence (NRI), reproductive tiller height (RTH), inflorescence rachis length (IRL), number of seeds/inflorescence (NSI), weight of a thousand seeds (WTS) and seed production (SP). Genetic divergence among the genotypes was estimated using the Tocher method and UPGMA clustering, based on the generalized Mahalanobis distance (D2 ii’). The Tocher and UPGMA optimization methods showed high concordance. The traits that most contributed to genetic divergence were RTH (23.59%), IRL (21.63%), WTS (16.67%) and SP (14.23%). The presence of genetic diversity made it possible to identify divergent genotypes and those with high means for the traits studied, allowing the selection of genotypes with significant breeding potential. Repeated cross-breeding of female superior plants with the genotypes Azulão and H20 can result in a high heterosis effect on seed production characteristics. RESUMO A utilização da divergência genética como base para a identificação de indivíduos superiores, com maior heterozigose, é importante diante da dificuldade de escolha de genótipos dissimilares, que apresentem média elevada para as características de interesse. O objetivo deste trabalho foi avaliar a divergência genética e a expressão dos caracteres da produção de sementes de dezessete híbridos apomíticos de Paspalum plicatulum × Paspalum guenoarum e dois genitores masculinos (P. guenoarum). O delineamento experimental utilizado foi o de blocos casualizados, com os genótipos arranjados individualmente em dez blocos. Foram avaliadas as seguintes características: total de perfilhos/planta (TP), perfilhos reprodutivos/planta (PR), número de racemos/inflorescência (NRI), altura dos perfilhos reprodutivos (APR), comprimento de inflorescência (CI), número de sementes/inflorescência (NSI), peso de mil sementes (PMS) e produção de sementes (PS). A divergência genética entre os genótipos foi estimada pelos métodos de agrupamento de Tocher e UPGMA, com emprego da distância generalizada de Mahalanobis (D2 ii’). Os métodos de otimização de Tocher e UPGMA foram concordantes entre si. As características APR (23,59%), CI (21,63%), PMS (16,67%) e PS (14,23%) foram as que mais contribuíram para a divergência genética. A presença de variabilidade genética permitiu a identificação de genótipos divergentes e com médias elevadas para os caracteres estudados, o que possibilita selecionar genótipos com elevado potencial para fins de melhoramento genético. O cruzamento repetido de plantas sexuais superiores com os genótipos Azulão e H20 pode proporcionar efeito heterótico elevado nos caracteres da produção de sementes.

This study was conducted to evaluate the use of chromium oxide and the content of fecal nitrogen to estimate forage intake by female lambs on Italian ryegrass pasture. The pasture was managed under different forage allowances (FA): 6, 9 and 12% BW. The experiment was a randomized split-split plot design, in which the forage allowances were considered as main plots, the phenological stages as subplots and methods to determine intake as sub-subplots. Forage intake, in the ryegrass vegetative stage, is independent of forage allowance. Lower allowances limit forage intake from the pre-flowering stage, while at the reproductive stage, intake was lower in FA6, intermediate in FA9 and higher in FA12. The estimation of organic matter intake by lambs on Italian ryegrass is similar when chromium oxide and fecal nitrogen are used as markers. The forage intake according to forage allowances depends on the sward structure and is limited by high stem mass at the end of the phenological cycle. RESUMO. Este experimento foi realizado para mensurar a ingestão de forragem por cordeiras, em pastagem de azevém, utilizando o óxido de cromo e o teor de nitrogênio fecal. A pastagem foi manejada sob distintas ofertas de forragem (OF): 6, 9 e 12% do PC. O delineamento experimental foi inteiramente casualizado, com estrutura de parcelas sub subdivididas, sendo as ofertas de forragem as parcelas principais, os estádios fenológicos, as subparcelas e os métodos de determinação da ingestão as sub sub-parcelas. A ingestão nos estádios vegetativo do azevém independe da oferta de forragem. As menores ofertas limitam a ingestão de forragem a partir do pré-florescimento enquanto no estádio reprodutivo do azevém a ingestão é menor na OF6, intermediária na OF9 e maior OF12. A estimativa da ingestão de matéria orgânica por cordeiras em pastagem de azevém é similar quando são utilizados o óxido de cromo e o nitrogênio fecal como marcadores. A ingestão de forragem em função das ofertas de forragem é dependente da estrutura do dossel e é limitada no final do ciclo do pasto em função da elevada massa de colmos.

This work was carried out in order to generate information on the tillering process and to contribute for the understanding of the defoliation process on Italian ryegrass (Lolium multiflorum Lam.) grazed by lambs under different herbage allowances: 6, 8 and 12 kg of dry matter per 100 kg of animal live weight per day. The grazing method was intermittent. The experimental design was completely randomized following a repeated measure arrangement, with three treatments and two area replications. The intensity of defoliation is greater at 6 and 9% herbage allowances. The defoliation interval is higher at 12% herbage allowance, intermediate at 9% and lower at 6%. The rates of tiller emergence, survival and death, stability index the tiller population are similar for the different herbage allowances and differ according to the phenological stage of ryegrass. Structural changes caused by canopy management with low herbage allowance and/or due to the advance in developmental stage of ryegrass alter defoliation strategies, with more intense and frequent grazing. Este trabalho foi conduzido com o objetivo de gerar informações sobre o processo de perfilhamento e contribuir para com o entendimento do processo de desfolhação do azevém (Lolium multiflorum Lam.) utilizado por cordeiras, submetidas a diferentes ofertas de forragem: 6; 8 e 12 kg de MS 100-1 kg de peso corporal. O método de pastejo foi intermitente. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo, três tratamentos e duas repetições de área. A intensidade de desfolhação é superior nas ofertas de forragem 6 e 9%. O intervalo entre desfolhações foi superior na oferta de forragem 12%, intermediária na oferta 9% e inferior na oferta 6%. As taxas de aparecimento, sobrevivência e mortalidade de perfilhos e o índice de estabilidade da população de perfilhos são similares nas ofertas de forragem e variam nos estádios fenológicos do azevém. Mudanças estruturais do dossel causadas pelo manejo com baixas ofertas de forragem e/ou pelo avanço do estádio fenológico do azevém alteram as estratégias de desfolhação, com pastejo realizado de forma mais intensa e frequente.

O consumo de forragem foi avaliado em novilhas de corte exclusivamente em pastagem de azevém (Lolium multiflorum Lam.) ou recebendo farelo de arroz integral (FAI) com ou sem adição de ionóforo. Foi usado o óxido de cromo como indicador da produção fecal. O delineamento experimental foi o inteiramente casualizado, com medidas repetidas no tempo, com três tratamentos e três repetições de área. Os animais foram considerados as unidades experimentais nas avaliações de consumo. O consumo de pasto pelas novilhas foi similar nos diferentes sistemas alimentares, ocasionando taxa de lotação semelhante. O fornecimento de farelo de arroz integral, com ou sem monensina, aumenta o consumo de matéria seca total. A adição de ionóforo ao FAI aumenta o desempenho individual das novilhas, sendo o seu uso recomendado quando existe o objetivo de reduzir a sua idade ao primeiro acasalamento. The forage intake was evaluated in beef heifers exclusively in Italian ryegrass (Lolium multiflorum Lam.) pasture or receiving rice bran with or without addition of ionophore. Chromic oxide was used as a fecal production indicator. The experimental design was completely randomized with repeated measures on time, three treatments and three area replicates. The animals were considered experimental units for intake evaluations. The pasture intake by heifers was similar at different feeding systems causing similar stocking rate. The supply of rice bran with or without monensin increased the total dry matter intake. The individual heifers performance was increased with ionophore addition to rice bran. Ionophore is recommended when there is a goal to reduce the age of beef heifers at their first mating.