High-resolution bulked segregant analysis enables candidate gene identification for bacterial wilt resistance in Italian ryegrass (Lolium multiflorum Lam.).

Bacterial wilt, caused by Xanthomonas translucens pv. graminis (Xtg), is a serious disease of economically important forage grasses, including Italian ryegrass (Lolium multiflorum Lam.). A major QTL for resistance to Xtg was previously identified, but the precise location as well as the genetic factors underlying the resistance are yet to be determined. To this end, we applied a bulked segregant analysis (BSA) approach, using whole-genome deep sequencing of pools of the most resistant and most susceptible individuals of a large (n = 7484) biparental F2 population segregating for resistance to Xtg. Using chromosome-level genome assemblies as references, we were able to define a ~300 kb region highly associated with resistance on pseudo-chromosome 4. Further investigation of this region revealed multiple genes with a known role in disease resistance, including genes encoding for Pik2-like disease resistance proteins, cysteine-rich kinases, and RGA4- and RGA5-like disease resistance proteins. Investigation of allele frequencies in the pools and comparative genome analysis in the grandparents of the F2 population revealed that some of these genes contain variants with allele frequencies that correspond to the expected heterozygosity in the resistant grandparent. This study emphasizes the efficacy of combining BSA studies in very large populations with whole genome deep sequencing and high-quality genome assemblies to pinpoint regions associated with a binary trait of interest and accurately define a small set of candidate genes. Furthermore, markers identified in this region hold significant potential for marker-assisted breeding strategies to breed resistance to Xtg in Italian ryegrass cultivars more efficiently.

Cytonuclear interplay in auto- and allopolyploids: a multifaceted perspective from the Festuca-Lolium complex.

Restoring cytonuclear stoichiometry is necessary after whole-genome duplication (WGD) and interspecific/intergeneric hybridization in plants. We investigated this phenomenon in auto- and allopolyploids of the Festuca-Lolium complex providing insights into the mechanisms governing cytonuclear interactions in early polyploid and hybrid generations. Our study examined the main processes potentially involved in restoring the cytonuclear balance after WGD comparing diploids and new and well-established autopolyploids. We uncovered that both the number of chloroplasts and the number of chloroplast genome copies were significantly higher in the newly established autopolyploids and grew further in more established autopolyploids. The increase in the copy number of the chloroplast genome exceeded the rise in the number of chloroplasts and fully compensated for the doubling of the nuclear genome. In addition, changes in nuclear and organelle gene expression were insignificant. Allopolyploid Festuca × Lolium hybrids displayed potential structural conflicts in parental protein variants within the cytonuclear complexes. While biased maternal allele expression has been observed in numerous hybrids, our results suggest that its role in cytonuclear stabilization in the Festuca × Lolium hybrids is limited. This study provides insights into the restoration of the cytonuclear stoichiometry, yet it emphasizes the need for future research to explore post-transcriptional regulation and its impact on cytonuclear gene expression stoichiometry. Our findings may enhance the understanding of polyploid plant evolution, with broader implications for the study of cytonuclear interactions in diverse biological contexts.

Effects of different fertilization methods on Lolium multiflorum Lam. growth and bacterial community in waste slag.

Waste slag has low nutrient content, so it has insufficient nutrient cycling and transformation in the soil ecosystem. There are few studies on the application of oligotrophic phosphate-solubilizing bacteria and phosphate (P) fertilizer to improve the properties of waste slags. In this study, three oligotrophic bacterial strains with P solubilizing activity, namely, Bacillus subtilis 2C (7.23 µg/mL), Bacillus subtilis 6C (4.07 µg/mL), and Bacillus safensis 2N (5.05 µg/mL), were isolated from waste slags. In the pot experiment, compared with no application of P fertilizer, inoculation of Bacillus subtilis 2C with a 50% recommended dose of P fertilizer significantly increased the available phosphorus (AP), total phosphorus (TP), and total nitrogen (TN) in slag by 33.16%, 76.70%, and 233.33%, respectively. The N, P uptake and fresh weight of Lolium multiflorum Lam. were significantly improved by 114.15%, 139.02%, and 100%, respectively. The analysis of the bacterial community showed that the application of P fertilizer decreased the diversity and richness of the bacterial community, and with the addition of phosphorus fertilizer and Bacillus subtilis 2C, the bacterial community in the slag developed towards eutrophication. Redundancy analysis (RDA) showed that the TP content in the slag was significantly correlated with the bacterial community (P = 0.001, < 0.01), followed by the TN content. This study on different P fertilizer application methods can provide some basic ideas for improving the performance of waste slag.

Effects of Pb-, Cd-resistant bacterium Pantoea sp. on growth, heavy metal uptake and bacterial communities in oligotrophic growth substrates of Lolium multiflorum Lam.

Phosphate-solubilizing bacteria (PSB) can accelerate phytoremediation, especially in those fertilized soils. However, PSB function in oligotrophic growth substrates remains poorly studied. In this study, we isolated lead (Pb)- and cadmium (Cd)-resistant PSB from contaminated sandy soil at an abandoned lubricant plant. The isolated Pantoea sp. PP4 (PP4 hereafter) can produce organic acid and IAA (Indole-3-acetic acid) and dissolve up to 238 mg/L of inorganic phosphate Ca2(PO4)3, exhibiting biosorption capability for Pb and bioprecipitation for Pb and Cd. In the sand pot experiment, inoculation of PP4 increased the accumulation of Pb and Cd in Lolium multiflorum Lam. by 28.9% and 95.5%, respectively, and increased the available phosphorous in oligotrophic river sand by 30.8% (P < 0.05). Meanwhile, the growth of Lolium multiflorum Lam. was also stimulated, resulting in 89.2%, 57.1%, 184.6%, and 28.5% increase in fresh weight, dry weight, root length, and shoot length, respectively. NMDS analysis showed that the bacterial communities in river sand were more clustered after inoculation with PP4. These results indicated that the application of Pantoea sp. PP4 can facilitate the phytoremediation of Pb and Cd in oligotrophic growth substrates, forming a convergent bacterial community. Our findings highlighted the importance of identifying ideal PSB to improve phytoremediation efficiency in oligotrophic environments.

Does the residual effect of n-fertilization applied on corn phase maintain forage production of the following pasture phase in an integrated crop-livestock system? / O efeito residual da adubação nitrogenada aplicada na fase de milho mantém a produção de forragem da fase pastagem em sucessão em um sistema de integração lavoura-pecuária?

Nutrient cycling represents an important nutrient source in the Integrated Crop-Livestock Systems (ICLS). In general, only the crop phase of the ICLS is fertilized, however little is known about this residual effect of nitrogen fertilization from summer crop to succeeding winter pasture. This research aimed to evaluate the forage growth dynamic and botanical composition of a mixed pasture of black oat (Avena strigosa Schreb) and ryegrass (Lolium multiflorum Lam.) affected by two canopy height managements (high and low) and nitrogen fertilization applied to either the summer crop (corn) or winter pasture phase of an ICLS. The experiment was established in 2012 in southern Brazil. Black oat and ryegrass were growing during winter season and corn (Zea mays L.) during summer season, being this paper related to the 2014 pasture period. Treatments were composed by two canopy heights (25 and 10 cm) and two N-Fertilization Times (N-Pasture or N-Corn) of 200 kg of N ha-1. Canopy height was regulated by beef steers grazing through continuous stocking with a variable stocking rate. Forage mass was lower in the 10 cm canopy height on average, however this forage mass was composed by greater proportion of ryegrass leaves and lower proportion of dead material in relation to the treatment with 25 cm canopy height. The N-fertilization applied directly on pasture phase (N-Pasture) increased forage mass, tiller population density, participation of ryegrass and ryegrass leaf proportion in the forage mass. Furthermore, when pasture was fertilized with N, the forage accumulation rate increased about 69%, highlighting that the corn N-fertilization did not present significant effect on forage productivity. The residual effect of corn N-fertilization was not enough to maintain high forage accumulation. Thus, the pasture N-fertilization is fundamental to keep high-productive crop-livestock system. (AU)

A ciclagem de nutrientes representa uma importante fonte de nutrientes em sistemas de Integração Lavoura-Pecuária (ILP). Em geral, apenas a fase de lavoura é fertilizada, entretanto pouco se sabe sobre esse efeito residual da adubação nitrogenada realizada na lavoura de verão para as pastagens de inverno em sucessão. Esse trabalho objetivou avaliar a dinâmica de acúmulo de forragem e a composição botânica de uma pastagem mista de aveia preta (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam.) manejada com duas alturas do pasto (alta e baixa) e com adubação nitrogenada realizada na cultura de grãos (milho) ou na fase pastagem de um sistema ILP. O experimento foi estabelecido em 2012 no sul do Brasil. Aveia preta e azevém eram cultivados durante o inverno e milho para grãos (Zea mays L.) era cultivado durante o verão, sendo esse trabalho relacionado ao período de pastagem em 2014. Os tratamentos foram compostos por duas alturas de manejo do pasto (25 e 10 cm) e duas épocas de adubação nitrogenada no sistema ILP (N-Pastagem ou N-Milho), na dose de 200 kg de N ha-1. A altura do pasto foi regulada por meio de pastejo com lotação contínua e taxa de lotação variável de novilhos de corte. Em média, a massa de forragem foi menor na altura do pasto de 10 cm, entretanto essa massa de forragem foi composta por uma maior proporção de folhas de azevém e menor proporção de material morto em relação ao tratamento com 25 cm. A adubação nitrogenada realizada diretamente na fase pastagem (N-Pastagem) aumentou a massa de forragem, a densidade populacional de perfilhos, a participação de azevém e a porcentagem de folhas de azevém na massa de forragem. Além disso, a adubação nitrogenada na fase pastagem aumentou a taxa de acúmulo de forragem em 69%, evidenciando que não há efeito significativo da adubação feita na lavoura de milho sobre a produtividade de forragem. O efeito residual da adubação nitrogenada na fase lavoura (milho) não foi suficiente para manter o alto acúmulo de forragem. Dessa forma, a adubação nitrogenada da fase pastagem em sistema ILP é fundamental para manter esses sistemas de produção agrícola e pecuária altamente produtivos. (AU)

Non-target-Site Resistance in Lolium spp. Globally: A Review.

The Lolium genus encompasses many species that colonize a variety of disturbed and non-disturbed environments. Lolium perenne L. spp. perenne, L. perenne L. spp. multiflorum, and L. rigidum are of particular interest to weed scientists because of their ability to thrive in agricultural and non-agricultural areas. Herbicides are the main tool to control these weeds; however, Lolium spp. populations have evolved multiple- and cross-resistance to at least 14 herbicide mechanisms of action in more than 21 countries, with reports of multiple herbicide resistance to at least seven mechanisms of action in a single population. In this review, we summarize what is currently known about non-target-site resistance in Lolium spp. to acetyl CoA carboxylase, acetohydroxyacid synthase, microtubule assembly, photosystem II, 5-enolpyruvylshikimate-3-phosphate synthase, glutamine synthetase, very-long chain fatty acids, and photosystem I inhibitors. We suggest research topics that need to be addressed, as well as strategies to further our knowledge and uncover the mechanisms of non-target-site resistance in Lolium spp.

Canopy structure and morphogenesis of Italian ryegrass intercropped with red clover under cutting intervals determined by thermal sum / Estrutura do dossel e morfogênese do azevém anual consorciado com trevo vermelho em intervalos de corte determinados por soma térmica

ABSTRACT: The canopy structure and morphogenesis of ryegrass (Lolium multiflorum Lam.) was investigated after it was over seeded with Tifton 85 (Cynodon spp.) and intercropped with red clover (Trifolium pratense L.). Time intervals between cuts were determined by different thermal sums (125, 250, 375, and 500 degree-days [DD]). Cuts were conducted at a height equivalent to 50% of the average canopy height. Morphogenic and structural data were collected from July to October of 2016 and 2017, from a completely randomized block experimental design. Canopy height, extended tiller height, pseudostem length, and forage mass were fitted to linear equations according to the thermal sums. Interaction of ryegrass with red clover was the highest (12.1%) for longer cut intervals (375 and 500 DD). The leaf appearance rate (0.0080 leaf/DD), phyllochron value (128.8 DD), and senescence rate (0.10 cm/DD) of ryegrass were comparable between the different intervals. The slowest elongation rate (0.06 cm/DD) with the shortest interval duration between cuts (171.6 DD) was observed in the 125 DD interval. According to the findings from this 2-year experiment, the use of a 250 DD cut interval was recommended between grazing events, taking into account the efficiency of forage use, ryegrass leaf, stem ratio, and interactions with red clover in the canopy under rotational stocking.

RESUMO: A estrutura do dossel e a morfogênese do azevém (Lolium multiflorum Lam.) foram investigadas após a sobressemeadura em Tifton 85 (Cynodon spp.) e consorciado com trevo vermelho (Trifolium pratense L.). Os intervalos de tempo entre os cortes foram determinados por diferentes somas térmicas (125, 250, 375 e 500 graus-dia [GD]). Os cortes foram realizados a uma altura equivalente a 50% da altura média do dossel. Os dados morfogênicos e estruturais foram coletados no período de julho a outubro de 2016 e 2017, em um delineamento experimental de blocos ao acaso. A altura do dossel, a altura estendida do perfilho, o comprimento do pseudocolmo e a massa de forragem se ajustaram a equações lineares de acordo com a soma térmica. A consorciação de azevém e trevo vermelho foi maior (12,1%) para intervalos de corte mais longos (375 e 500 GD). A taxa de aparecimento foliar (0,0080 folha/GD), filocrono (128,8 GD) e a taxa de senescência (0,10 cm /GD) do azevém não foram diferentes entre os intervalos de corte. A menor taxa de elongação (0,06 cm/GD) e duração de elongação (171,6 GD) foi observada no menor intervalo entre cortes, 125 GD. De acordo com os achados deste experimento de dois anos, recomenda-se o uso de um intervalo de corte de 250 GD entre os eventos de pastejo, levando em consideração a eficiência do uso de forragem, proporção de folhas e colmo de azevém e trevo vermelho no dossel, sob lotação rotativa.

Nitrogen fertilization of self-seeding Italian ryegrass: effects on plant structure, forage and seed yield / Adubação nitrogenada em azevém anual, proveniente de ressemeadura natural: efeitos sobre a estrutura de plantas, produção de forragem e de sementes

ABSTRACT: This study aimed to evaluate the effect of different levels of self-seeding Italian ryegrass (Lolium multiflorum Lam.) and nitrogen rates - applied additionally after two defoliations - on plant structure, in forage and seed yield. Levels of self-seeding were classified as very high (777 kg ha-1), high (736 kg ha-1), intermediate (624 kg ha-1), and low (234 kg ha-1). Populations were fertilized with zero, 20.25, 40.50, and 60.75 kg ha-1 of supplemental nitrogen applied after two defoliations; respectively, in very high, high, intermediate, and low levels. Higher levels of self-seeding promoted greater forage yield and uniformity of vegetation structure. Number of fertile tillers and number of seeds per plant have benefited by the combination of high self-seeding and supplemental nitrogen fertilization. Despite influencing the uniformity and amount of forage obtained in two defoliations, the very high and low self-seeding levels did not differ in Italian ryegrass seed production. However, linear addition for this same variable was obtained with the inclusion of supplemental nitrogen fertilization. In pastures from low and intermediate self-seeding levels, total dry mass increases linearly with the levels of nitrogen fertilization assessed in this research.

RESUMO: O objetivo deste estudo foi avaliar o efeito de diferentes níveis de ressemeadura natural de azevém anual (Lolium multiflorum Lam.), bem como, doses suplementares de nitrogênio sobre a estrutura de plantas, produção de forragem e de sementes. Os níveis de ressemeadura foram classificados como: muito elevada (777 kg ha-1); elevada (736 kg ha-1); intermediária (624 kg ha-1) e baixa (234 kg ha-1). Populações oriundas destes níveis foram fertilizadas com zero, 20.25, 40.50, and 60.75 kg ha-1 de nitrogênio, aplicado de forma suplementar após duas desfolhas. Maiores níveis de ressemeadura propiciaram maior colheita de forragem e maior uniformização da estrutura da vegetação. A quantidade de perfilhos férteis e o número de sementes por planta foram beneficiados pela combinação de elevada ressemeadura e aplicação de nitrogênio. Apesar de influenciar a uniformização e a quantidade de forragem obtida em duas desfolhas, os níveis de ressemeadura natural, muito elevada e baixa não diferiram entre si na produção de sementes no ano subsequente. Todavia, acréscimo linear para esta mesma variável foi verificado com avanço suplementar da adubação nitrogenada. Em pastagem de azevém anual proveniente dos níveis baixo e intermediário, a produção de massa seca total é acrescida linearmente com os níveis de fertilização avaliados no presente trabalho.

Comparative Physiological and Transcriptomic Analyses Reveal Mechanisms of Improved Osmotic Stress Tolerance in Annual Ryegrass by Exogenous Chitosan.

Water deficit adversely affects the growth and productivity of annual ryegrass (Lolium multiflorum Lam.). The exogenous application of chitosan (CTS) has gained extensive interests due to its effect on improving drought resistance. This research aimed to determine the role of exogenous CTS on annual ryegrass in response to water stress. Here, we investigated the impact of exogenous CTS on the physiological responses and transcriptome changes of annual ryegrass variety "Tetragold" under osmotic stress induced by exposing them to 20% polyethylene glycol (PEG)-6000. Our experimental results demonstrated that 50 mg/L exogenous CTS had the optimal effect on promoting seed germination under osmotic stress. Pre-treatment of annual ryegrass seedlings with 500 mg/L CTS solution reduced the level of electrolyte leakage (EL) as well as the contents of malondialdehyde (MDA) and proline and enhanced the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbic acid peroxidase (APX) under osmotic stress. In addition, CTS increased soluble sugars and chlorophyll (Chl) content, net photosynthetic rate (A), stomatal conductance (gs), water use efficiency (WUE), and transpiration rate (E) in annual ryegrass seedlings in response to three and six days of osmotic stress. Transcriptome analysis further provided a comprehensive understanding of underlying molecular mechanisms of CTS impact. To be more specific, in contrast of non-treated seedlings, the distinct changes of gene expressions of CTS-treated seedlings were shown to be tightly related to carbon metabolism, photosynthesis, and plant hormone. Altogether, exogenous CTS could elicit drought-related genes in annual ryegrass, leading to resistance to osmotic stress via producing antioxidant enzymes and maintaining intact cell membranes and photosynthetic rates. This robust evidence supports the potential of the application of exogenous CTS, which will be helpful for determining the suitability and productivity of agricultural crops.

Growth improvement of Lolium multiflorum Lam. induced by seed inoculation with fungus suspension of Xerocomus badius and Serendipita indica.

In this study, a pot experiment was carried out in greenhouse to investigate the potentials of Xerocomus badius and Serendipita indica to penetrate and colonize roots of ryegrass (Lolium multiflorum Lam.) and to induce beneficial effects on seed germination and seedling growth. The results showed that X. badius and S. indica successfully colonized in the root system of L. multiflorum seedlings and the root colonization rate was 72.65% and 88.42%, respectively. By microscopy, the hyphae, chlamydospores and spores produced by S. indica were observed in roots cortex of L. multiflorum seedlings. In comparison with the non-inoculated seedlings, seedlings inoculated with X. badius and S. indica showed significant increase in growth parameters with plant height, basal diameter, biomass accumulation, relative growth rate, leaf relative water content and chlorophyll content. Also, we found that seedlings inoculated with S. indica exhibited a greater growth-promotion as compared with X. badius-inoculated seedlings. No significant influence of the two fungus application has been observed with respect to seed germination. It suggested that well establishments of mutualistic symbiosis between L. multiflorum and X. badius or S. indica were not so essential to seed germination but contributed highly to the survival and growth of the seedlings.

Análise bioeconômica do farelo de arroz na recria de bezerras de corte em azevém / Bioeconomics analyses of rice brain use for reaning of beef heifers on Italian ryegrass pasture

Objetivou-se avaliar a economicidade, o desempenho produtivo e o desenvolvimento das estruturas corporais relacionadas ao trato reprodutivo de bezerras de corte mantidas exclusivamente em pastagem de azevém (Lolium multiflorum Lam.) ou em pastagem de azevém recebendo 0,5 e 1,0% do peso corporal (PC) de farelo de arroz integral (FAI) como suplemento. O método de pastejo foi o rotativo, e o intervalo entre pastejos foi estabelecido considerando-se a soma térmica necessária para a emissão de 1,5 folha de azevém (187,5ºC). O delineamento experimental foi o inteiramente ao acaso, com medidas repetidas no tempo. O ganho médio diário das bezerras não diferiu entre os sistemas alimentares. A taxa de lotação e o ganho de peso por área foram maiores quando as bezerras receberam 1,0% do PC de farelo de arroz integral. A maior margem bruta foi observada quando as bezerras receberam 0,5% de FAI. O custo variável obtido para os diferentes sistemas alimentares apresentou comportamento crescente em função dos níveis de FAI, superando o uso exclusivo do azevém em 49,4% e 81,8%. O peso corporal final, o escore de condição corporal e o escore do trato reprodutivo não diferiram entre os sistemas alimentares. Considerando-se um animal adulto com peso corporal médio de 450kg, as bezerras ao início do experimento apresentaram 34% do peso corporal adulto e peso corporal final médio de 56% do peso adulto. A utilização de níveis de farelo de arroz integral (FAI) na recria de bezerras de corte sob pastejo rotativo em azevém não modifica o ganho médio diário e o escore do trato reprodutivo. O fornecimento de 1% de FAI mostrou efeito substitutivo, proporcionando um incremento de 31,2% na taxa de lotação e de 38,3% no ganho por área. O sistema alimentar AZ0,5 permitiu uma maior margem bruta; já o retorno financeiro direto foi positivo em todos os sistemas alimentares, com melhor retorno calculado para o uso exclusivo do azevém.(AU)

The experiment was carried out with the objective of evaluating the gross margin, the productive and reproductive performance of beef heifers kept exclusively on ryegrass pasture (Lolium multiflorum Lam.) or ryegrass receiving 0.5 and 1.0% of body weight (BW) of whole rice bran as supplement. The grazing method was the rotational and the interval between grazings was set by the thermal sum required for the appearing of 1.5 ryegrass leaf (187.5ºC). The experimental design was completely randomized with repeated measures. Heifers average daily gain did not differ between the feeding systems. The stocking rate and weight gain per area were higher when heifers received 1.0% BW of whole rice bran. The higher gross margin was observed when heifers received 0.5% BW. The variable cost obtained for the different feeding systems showed increasing behavior depending on the WRB levels, surpassing the exclusive use of ryegrass in 49.4% and 81.8%. The final body weight, body condition score and reproductive tract score did not differ between the feeding systems. Considering an adult animal with an average body weight of 450kg, the heifers at the beginning of the experiment showed 34% of mature body weight and final average body weight of 56% of adult weight. The use of rice bran levels (FAZ) in the rearing of beef heifers under rotational grazing on ryegrass does not change the average daily gain and the reproductive tract score. The supply of 1% FAI showed substitutive effect, providing an increase in capacity of 31,2% and 38.3% rate of the gain per area. The food system AZ0,5 allowed a higher gross margin, as the economic return was positive in all food systems, with better return calculated for the exclusive use of ryegrass.(AU)

Ingestive behavior and forage intake of heifers receiving corn grain with or without crude glycerin on italian ryegrass pasture / Comportamento ingestivo e ingestão de forragem por bezerras recebendo grão de milho com ou sem glicerina bruta em pastagem de azevém

The objective was to analyze the ingestive behavior, forage intake and pasture characteristics when beef heifers are kept exclusively on ryegrass pasture (Lolium multiflorum Lam.) or receiving ground corn grain as supplement (0.9% of body weight (BW )) with or without addition of crude glycerin (0.2% BW). Experimental animals were Angus heifers with initial age and body weight of eight months and 166.2 ± 9.5 kg, respectively. The grazing method was continuous with variable number of animals. The experimental design was completely randomized with repeated measures. Dry matter intake was estimated using chromium oxide as an indicator of fecal output. Heifers ingested a similar amount of dry matter and neutral detergent fiber. Forage intake was 19.0% lower when heifers receiving ground corn grain as supplement with or without addition of crude glycerin and these reduction in dry matter intake of forage provided increase of 38.2% in the stocking rate. Heifers that received crude glycerin as a supplement spent more time in the trough than heifers that received only ground corn grain.

Objetivou-se avalizar o comportamento ingestivo, ingestão de forragem e as características da pastagem quando bezerras de corte são mantidas exclusivamente em pastagem de azevém (Lolium multiflorum Lam.) ou recebendo grão de milho quebrado como suplemento (0,9% do peso corporal (PC)) com ou sem adição de glicerina bruta (0,2% PC). Os animais experimentais foram bezerras Angus com idade e peso inicial de oito meses e 166,2 ± 9,5 kg, respectivamente. O método de pastejo foi o contínuo com número variável de animais. O delineamento experimental foi o inteiramente casualizado com medidas repetidas no tempo. A ingestão de matéria seca foi estimada usando óxido de cromo como indicador de produção fecal. As bezerras ingeriram similares quantidades de matéria seca e fibra em detergente neutro. A ingestão de forragem foi 19.0% menor quando as bezerras recebem grão de milho quebrado como suplemento com ou sem adição de glicerina bruta e essa redução na ingestão de matéria seca de forragem promove aumento de 38,2% na taxa de lotação. Bezerras que recebem glicerina bruta como suplemento permanecem mais tempo no cocho do que bezerras que recebem somente grão de milho quebrado.

Desempenho de bezerras de corte em pastagem de azevém recebendo farelo de arroz com ou sem monensina / Beef heifers performance in ryegrass pasture supplemented with rice bran with or without monensin

Foi estudado o desempenho de bezerras de corte em pastagem de azevém (Lolium multiflorum Lam.), com animais exclusivamente em pastejo ou recebendo farelo de arroz integral (FAI) em nível de 0,8% do peso corporal, associado ou não à monensina. O método de pastejo foi contínuo com número variável de animais. O delineamento experimental foi o inteiramente ao acaso, com medidas repetidas no tempo, com três tratamentos e três repetições de área. O uso de FAI associado ou não à monensina não expressou alteração na área pélvica das bezerras, na taxa de lotação e no ganho de peso por área. As bezerras que receberam FAI, com ou sem monensina, apresentaram maior ganho diário de peso corporal, peso corporal, escore de condição corporal e relação peso corporal:altura. O fornecimento de suplementação energética para bezerras de corte é uma alternativa viável em sistemas de produção que visam à redução da idade ao primeiro acasalamento.(AU)

The experiment was carried out with the objective of evaluating beef cattle heifer performance when exclusively grazing Italian ryegrass (Lolium multiflorum Lam.) pasture or supplemented with whole rice bran (WRB), equivalent to 0.8% of body weight, associated or not with monensin. The grazing method was "put-and-take" stocking, in a completely randomized experimental design, with replicated measures over time, with three treatments and three replications of area. The use of WRB, associated or not with monensin, did not affect heifers' pelvic area, stocking rate and area weight gain. Animals fed WRB, with or without monensin, showed greater average daily gain, body weight, body condition score, and body weight:height ratio. Energetic supplementation for beef heifers is one viable option in production systems seeking age reduction at the first mating.(AU)

Relationship between the morphogenesis of Italian ryegrass cv. 'BRS Ponteio' with forage and seed production / Relação entre as características morfogênicas do azevém anual cv. 'BRS Ponteio' com a produção de forragem e de sementes

This study aims to verify, accurate and precisely, the responses of Italian ryegrass 'BRS Ponteio' cultivar to different frequencies of defoliation for forage production and especially for seed production. For this purpose, a randomized block design experiment with four replications was conducted. Four frequencies of defoliation were applied (zero, one, two, and three) based on the thermal sum, evaluating the rate of leaf appearance (LAR), phyllochron (P), leaf expansion rate (LER), leaf senescence rate (LSR), stems expansion rate (SER), tillering rate (TR), leaf life span (LL), forage production, proportion of leaf blades, stems plus sheaths, senescent material, and inflorescences, as well as seed production. Second defoliation noticeably altered the morphogenic plant responses, reduced expansion rates and leaf appearance, increased rates of tillering and stems expansion. This phenotypic maintained a high seed production and provided a harvest of forage mass 100% higher than the collected mass in the first cutting. Third defoliation led to an increase of 100% of the harvested forage mass; however, it caused drastic and negative changes in the morphogenic characteristics and seed yielding.

O presente estudo teve o objetivo de verificar, de forma precisa e detalhada, as respostas da cultivar de azevém anual 'BRS Ponteio', às diferentes frequências de desfolha para a produção de forragem e de sementes. Realizou-se, para tanto, um experimento com delineamento de blocos casualizados com quatro repetições. Foram aplicadas quatro frequências de desfolhas (sem, uma, duas e três) baseando-se no acúmulo térmico, onde se avaliou a taxa de aparecimento de folhas (TApF), o filocrono (F), a taxa de expansão de folhas (TEF), taxa de senescência de folhas (TScF), taxa de expansão dos colmos (TEC), taxa de perfilhamento (TP), duração de vida da folha (DVF), produção de forragem, proporção de lâminas foliares, colmos mais bainhas, material senescente e inflorescências em cada tratamento, bem como a produção de sementes. A segunda desfolha alterou marcadamente as respostas morfogênicas da planta, reduziu as taxas de expansão e aparecimento de folhas e aumentou as taxas de perfilhamento e de expansão do colmo. Esta plasticidade fenotípica manteve a alta produção de sementes da planta e propiciou a colheita de massa de forragem 100% superior à massa colhida no primeiro corte. A terceira desfolha propiciou o aumento de 100% da massa de forragem colhida, todavia, promoveu alterações drásticas e negativas nas características morfogênicas e no rendimento de sementes.

Aspectos qualitativos e produção de biomassa em pastos de aveia e azevém cultivados puros ou consorciados e submetidos a pastejo leniente / Qualitative aspects and biomass production in oats and ryegrass pastures cultivated pure or intercropping and subjected to lenient grazing

Pastos consorciados de aveia e azevém anual têm sido recomendados para uso no inverno/primavera em ambientes subtropicais. No entanto, o impacto do pastejo leniente sobre parâmetros qualitativos e produtivos destes, comparativamente aos seus monocultivos, é pouco conhecido. Objetivou-se avaliar possíveis variações nas composições morfológica e bromatológica, além da produção de biomassa em pastos de aveia-preta (Avena strigosa cv. IAPAR 61) e azevém anual (Lolium multiflorum Lam. cv. comum) quando cultivados puros ou em consórcio ao longo de toda estação de crescimento e submetidos a pastejo leniente. Os três tratamentos (aveia pura, azevém puro e aveia + azevém em consórcio) foram distribuídos em um delineamento em blocos completos ao acaso, com quatro repetições. Novilhas da raça Holandesa foram utilizadas como agentes de desfolhação, e os pastos foram rebaixados em 40% da altura inicial quando as alturas atingiam 17, 20 e 23cm para o azevém, o consórcio e a aveia, respectivamente. A relação lâmina:colmo diminuiu com o avanço da estação de crescimento em todos os tratamentos, mas a proporção de colmos no estrato pastejável se manteve abaixo de 20% da matéria seca até o início do estádio de desenvolvimento reprodutivo, independentemente do tipo de pasto. Os teores de proteína bruta e fibra em detergente neutro no estrato pastejável foram, respectivamente, superiores a 16% e inferiores a 50% nos quatro primeiros ciclos de pastejo. O consórcio e o azevém puro apresentaram as maiores taxas de acúmulo médio de forragem (32,6kg MS ha-1 dia-1), porém o maior período de utilização do consórcio resultou em maior produção total de matéria seca (4809kg MS ha-1). O pastejo leniente não prejudica a qualidade da forragem no estrato pastejável durante todo o estádio de desenvolvimento vegetativo de pastos anuais de inverno. A associação entre aveia-preta e azevém anual aumenta a produção de matéria seca total de forragem em comparação aos mesmos pastos cultivados puros.

Mixed pastures of oats + annual ryegrass have been considered a good alternative for animal feeding during the winter/spring period in subtropical regions. However, the impacts of lenient grazing under their qualitative and productive aspects, when compared to their monoculture, remain unclear. Thus, the aim of this study was to evaluate the morphological and chemical composition and biomass production of black oat (Avena strigosa cv. IAPAR 61) and annual ryegrass (Lolium multiflorum Lam cv. common) swards cultivated pure or intercropped, throughout the growing season and submitted to lenient grazing. Treatments (oats, annual ryegrass and intercropping oats + annual ryegrass) were arranged in a complete randomized block design with four replications. The pastures were defoliated in 40% of pre-grazing height by Holstein heifers, when the heights reached 17, 20 and 23cm for the ryegrass, intercrop and oat, respectively. The leaf blade:stem ratio decreased with the advance of the growing season for all treatments, but the proportion of stems in the grazed stratum remained lower than 20% of dry matter until the pastures begun reproductive development. Similarly, the crude protein (CP) and neutral detergent fiber (NDF) levels in grazed stratum were, respectively, above 16% and below 50% from the first to fourth grazing cycles. Mixed pastures of black oat + ryegrass and ryegrass alone had higher forage accumulation rate (average = 32.6kg DM ha-1 day-1), but mixed pastures were used for a longer period, resulting in a greatest total DM production (4809kg DM ha-1). Lenient grazing does not reduce the forage quality in potential grazing layer throughout the growing vegetative stage. Intercropping black oat and ryegrass increases total DM production when compared to their monocultures.

Características produtivas da consorciação de trevo-persa e azevém submetidos a pastejo / Productive characteristics of intercropping persian clover and ryegrass submitted to grazing

Este estudo teve como objetivo avaliar o efeito de diferentes intervalos entre pastejos sobre as características produtivas de trevo-persa e azevém, consorciados e manejados sob lotação rotacionada, nos anos de 2009 e 2010. Os tratamentos consistiram em quatro intervalos entre pastejos (tempo para o surgimento de 2,5; 3,5; 4,5 e 5,5 folhas em plantas de trevo-persa), em delineamento de blocos completos ao acaso, com seis repetições. As variáveis analisadas foram: índice de área foliar, área foliar, altura do pasto e de plantas, comprimento de perfilhos/ramificações, taxa de acúmulo de matéria seca e produção de matéria seca. O índice de área foliar do dossel e do trevo-persa foi maior no intervalo de 5,5 folhas nos anos de 2009 e 2010. No ano de 2009, maiores valores de área foliar foram obtidos nos intervalos de 3,5 e 4,5 folhas e não se observou efeito dos intervalos entre pastejos sobre essa variável em 2010. Maiores intervalos entre pastejos proporcionaram maior altura do pasto e de plantas e também maior comprimento de perfilhos e ramificações. A produção de matéria seca do trevo-persa foi maior em 2010, ao passo que, para azevém, maior produção foi encontrada em 2009. A produção de matéria seca total foi maior no intervalo de 5,5 folhas. A taxa de acúmulo de matéria seca foi maior no intervalo de 5,5 folhas em 2009 e no intervalo de 2,5 folhas em 2010. As características produtivas da consorciação trevo-persa e azevém anual são modificadas pelos intervalos entre pastejos. Recomendam-se intervalos de até 3,5 folhas surgidas, em consorciação de trevo-persa e azevém anual, os quais proporcionam menor alongamento de caules associado à menor presença de material morto, o que, provavelmente, melhora a qualidade da forragem colhida.

The aim of this trial was to study the effect of different grazing intervals on productive characteristics of persian clover and ryegrass, in consortium and managed under rotational stocking during the years 2009 and 2010. Treatments were composed of four grazing intervals (time to onset of 2.5; 3.5; 4.5 and 5.5 leaves in persian clover plants) allocated in completely randomized blocks, with six replications. Leaf area index (LAI), leaf area, pasture and plants height, length of tillers/branches, rate of dry matter accumulation and dry matter yield were evaluated. The leaf area index of the canopy and the persian clover was higher in the interval of 5.5 leaves in years 2009 and 2010. In 2009, higher values of leaf area were obtained in intervals of 3.5 and 4.5 leaves and there no was effect of grazing intervals on this variable in 2010. Higher grazing intervals provided greater pasture height and plant height and also greater tiller and branch length. The dry matter production of persian clover was higher in 2010, while for ryegrass highest yields were found in 2009. Total dry matter yield was higher in the interval of 5.5 leaves. The rate of dry matter accumulation was higher in the interval of 5.5 leaves in 2009 and in the interval of 2.5 leaves in 2010. The productive characteristics of a of mixture persian clover and ryegrass are modified by the grazing intervals. It is recommended intervals up to 3.5 of appeared leaves with a mixture of persian clover and ryegrass, which provides lower elongation of stems associated with a lower presence of dead material, which probably improves the quality of the harvested forage.

Consumo de forragem por novilhas de corte recebendo farelo de arroz com e sem ionóforo / Forage intake by beef heifers receiving rice bran with and without ionophore

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.

Effects of olive mill wastewater physico-chemical treatments on polyphenol abatement and Italian ryegrass (Lolium multiflorum Lam.) germinability.

Direct spreading on agricultural lands may represent an environmentally friendly disposal method and a possible use of water and nutrients from olive mill wastewaters (OMWs). However, the agronomic use of OMWs is limited, among others by polyphenols, which exert phytotoxic effects. Activated charcoal (AC) has been recognized as a very effective agent for polyphenol abatement, as it enables an irreversible process of phenol adsorption. Addition of calcium hydroxide (Ca(OH)2) has also been described as a cheap and effective method in polyphenols abatement. However, the effects of Ca(OH)2 addition to OMW on seed germination are unclear. In this paper, the effects of AC and/or Ca(OH)2 on OMW polyphenols abatement, and Lolium multiflorum seed germination have been investigated. The highest polyphenols removal, approximately 95%, was observed when 80 g L(-1) of AC was added to OMWs (the maximum dose in this investigation). The addition of Ca(OH)2 not only improved the effectiveness of the AC treatment but also resulted in a significant rise in Lolium seed germination at the highest AC doses (60 and 80 g L(-1)). Considering the high salinity (7300 µS cm(-1)) of these wastewaters, low quantities of Ca(OH)2 may also exert a protective effect on soil structure counteracting the sodium-induced dispersion through the binding action of calcium cation on clays and organic matter.

Diferentes massas de forragem sobre as variáveis morfogênicas e estruturais de azevém anual / Different herbage masses on morphogenetic and structural traits of Italian ryegrass

Características morfogênicas e estruturais de azevém (Lolium multiflorum Lam.) foram avaliadas sob pastejo de borregas, em diferentes massas de forragem (MF): "Alta", "Média" e "Baixa", correspondentes a 1800-2000; 1400-1600 e 1000-1200kg ha-1 de matéria seca (MS), respectivamente. O delineamento experimental foi inteiramente casualizado, com três tratamentos e duas repetições de área. O método de pastejo foi de lotação contínua, com número variável de animais. Os dados foram submetidos a análises de correlação e regressão polinomial. A altura do pseudocolmo, o comprimento de lâminas intactas e desfolhadas e o número de folhas em senescência de azevém aumentaram linearmente com a elevação dos valores das massas de forragem. O número de folhas verdes ajustou-se ao modelo de regressão quadrático; o número de folhas em expansão e a densidade populacional de perfilhos não se ajustaram a nenhum modelo de regressão. Em pastagem de azevém, o manejo com massas de forragem dentro da faixa compreendida entre 1.100 e 1.800kg ha-1de MS não provoca alterações nas características morfogênicas dessa gramínea, mas causa diferenças nas características estruturais do dossel. Quando o azevém é manejado com 1.460kg ha-1de MS, seus perfilhos mantêm maior número de folhas verdes e com 1.800kg ha-1 de MS existe maior número de lâminas foliares em senescência e com maior comprimento.

Morphogenetic and structural characteristics of Italian ryegrass (Lolium multiflorum Lam.), utilized by female lambs and managed with different forage masses (FM) were studied. The experimental design was completely randomized, with two area replications and three treatments, consisting of forage masses: "High", "Mean" and "Low", corresponding to 1,800-2,000; 1,400-1,600 and 1,000-1,200kg ha-1 of dry matter (DM), respectively. The grazing method was continuous with variable stocking rate. Data were subjected to correlation analysis and polynomial regression. Pseudo stem's height and length of the intact and defoliated leaf blades and number of senescent leaves of Italian ryegrass increased linearly with the increase of forage mass. Number of green leaves was adjusted to the quadratic regression model, number of leaves in elongation and tiller population density did not adjust to any regression model. Management of Italian ryegrass with forage masses between 1,100 and 1,800kg ha-1of DM did not cause changes in its morphogenetic characteristics, but causes differences in the structural characteristics of the canopy. When managed with 1,460kg ha-1of DM, tillers of Italian ryegrass maintain greater number of green leaves. Meanwhile, when managed with 1,800kg ha-1of DM it has a higher number of leaf blades in senescence, and leaves with greater length.

Relationship between diurnal grazing time and herbage intake in dairy cows in rotational grazing / Inter-relação entre o tempo de pastejo diurno e o consumo de forragem em vacas leiteiras em pastejo rotativo

The aim of this study was describe the relationship between grazing time and herbage intake and identify tools to grazing management of dairy cows grazing Italian ryegrass (Lolium multiflorum Lam.) on a rotational grazing method. Six dairy cows in mid-lactation period were allowed to graze paddocks during three grazing cycles. During each cycle cows grazed two paddocks with 9 days of occupation by paddock and an herbage allowance of 30kg DM cow-1 day-1. Measurements were made in the last 9 days of each period and during intervals between cycles cows grazed an adjacent area with a mixed of temperate species. It was compared three grazing cycles and cows eating similar herbage amount with different daily grazing time. Independently of herbage intake, daily grazing time increased 12min by cm of the reduction on leaf height. Reductions on efficiency to graze are clearly associated to structural traits of canopy as proximity to ground level and stems + pseudo-stems content on the graze layer. In conclusion, under rotational grazing, daily grazing time is strongly associated with leaf height in the grazing layer, but it is not a good indicator of DM herbage intake. Structural traits of canopy are clearly associated with efficiency to graze, independently of daily herbage intake.

Objetivou-se descrever a relação entre o tempo de pastejo e o consumo de forragem e identificar possíveis indicadores de manejo para vacas leiteiras em pastos de azevém (Lolium multiflorum Lam.) no método rotativo. Foram utilizadas seis vacas leiteiras no terço médio de lactação durante três ciclos de pastejo. Em cada ciclo, os animais tiveram acesso a dois piquetes com nove dias de ocupação e oferta de forragem de 30kg MS vaca-1 dia-1. As medidas foram realizadas nos últimos nove dias de cada ciclo e, nos intervalos entre ciclos, os animais permaneceram em área adjacente com acesso a uma mistura de espécies forrageiras de clima temperado. Comparando os três ciclos, foi possível observar que as vacas obtiveram semelhante consumo de forragem com diferentes tempos de pastejo diário. Independente da quantidade de forragem ingerida, o tempo de pastejo diário aumentou 12min por cm de redução na altura residual de lâminas foliares e reduções na eficiência de pastejo foram claramente associadas a características estruturais da pastagem, como, a proximidade ao solo e a proporção de colmos + pseudocolmos no estrato pastejado. Em conclusão, sob pastejo rotativo, o tempo de pastejo está intimamente associado com a altura residual de folhas, mas não é um bom indicador do consumo de forragem. As características estruturais do pasto são claramente associadas à eficiência de pastejo, independente do consumo diário de forragem.