Comparative growth and management of white and red clovers

peer-reviewedThe aim of this paper is to provide the underpinning scientific basis for the optimum management of white and red clovers. Critical morphological and canopy characteristics which influence the yield and persistence of white and red clover in swards, and how management factors (choice of cultivar, defoliation and nitrogen (N) fertilizer) modify these are considered. Canopy development is vitally important as it determines the extent to which a) light is intercepted for photosynthesis needed for growth and b) the base of the sward is deprived of the red component in daylight, inhibiting branching of stolons and crowns in white and red clover, respectively. The role of cultivar, defoliation and N fertilizer in determining yield and persistence of the two legumes, mainly in mixtures with grass, are discussed principally in terms of morphological development and exploitation of light. It is concluded that optimum management for grass/white clover places emphasis on building up stolons and maximising contribution of clover leaf area to the upper layers of the mixed canopy and, while red clover is more competitive to grass than white clover, that benefit is lost when a grass/red clover sward is grazed

Leaf appearance of annual clovers responds to photoperiod atemergence

Leaf appearance rate and time to canopy expansion of four annual clover species (arrowleaf, balansa,gland and Persian) were quantified in field and controlled environment studies. Crops sown in autumn,which experienced shortening daylengths at emergence, had a slower rate of leaf production and con-sequently took a longer time to initiate branching, than spring-sown crops. When autumn-sown ‘Bolta’balansa clover emerged on the shortest day in winter (21 June), the rate of leaf appearance was lengthenedby 4◦C d/leaf/h. When the same species emerged after the shortest day, into an increasing photoperiod,the phyllochron was shortened by 5◦C d/leaf/h. This influence of photoperiod on the phyllochron conse-quently altered the time to axillary leaf production (branching). Throughout all sowing dates, phyllochronwas the fastest for ‘Prima’ gland (33–91◦C d/leaf) and slowest for ‘Cefalu’ arrowleaf (53–116◦C d/leaf)clovers. ‘Bolta’ balansa was 44–82◦C d/leaf and ‘Mihi’ Persian 61–93◦C d/leaf. The response of phyllochronto photoperiod suggests these annual clovers should be sown in late summer or early autumn to initiateaxillary leaf production as soon as possible to ensure maximize dry matter for early spring

Modelling seasonality of dry matter partitioning and root maintenance respiration in lucerne (Medicago sativa L.) crops

In lucerne, a dynamic fraction of total daily assimilates is allocated to the root system and the amount partitioned differs in response to seasonal environmental stimuli. This study proposes a simple framework to quantify this dynamic for inclusion in lucerne simulation models. The framework incorporates recent findings on radiation-use efficiency, radiation interception, and dry matter (DM) partitioning to shoots and roots in response to environmental factors. Results showed that the root mean squared deviation (RMSD) between observed and simulated values was 20% of the mean for shoot biomass and 24% for leaf area index. However, there was systematic bias (73% of RMSD) between observed and simulated root biomass (RMSD = 35%). This was caused by the initial assumption of a constant rate for root maintenance respiration (Rm) of 0.015 g/g.day in the model calculations. Sensitivity analysis, with constant Rm values that ranged from 0.005 to 0.030 g/g.day, failed to improve the prediction of root biomass. The modelling exercise suggested the existence of a systematic pattern of change in Rm from 0.035 g/g.day in summer to <0.005 g/g.day in winter. When this seasonality was incorporated, the accuracy of root DM simulations improved (RMSD = 14%). The possible existence of a seasonal Rm in lucerne, unveiled by this modelling approach, needs to be validated with an independent dataset

Comparative growth and management of white and red clovers

The aim of this paper is to provide the underpinning scientific basis for the optimum management of white and red clovers. Critical morphological and canopy characteristics which influence the yield and persistence of white and red clover in swards, and how management factors (choice of cultivar, defoliation and nitrogen (N) fertilizer) modify these are considered. Canopy development is vitally important as it determines the extent to which a) light is intercepted for photosynthesis needed for growth and b) the base of the sward is deprived of the red component in daylight, inhibiting branching of stolons and crowns in white and red clover, respectively. The role of cultivar, defoliation and N fertilizer in determining yield and persistence of the two legumes, mainly in mixtures with grass, are discussed principally in terms of morphological development and exploitation of light. It is concluded that optimum management for grass/white clover places emphasis on building up stolons and maximising contribution of clover leaf area to the upper layers of the mixed canopy and, while red clover is more competitive to grass than white clover, that benefit is lost when a grass/red clover sward is grazed

Biomassa uit natuur & landschap

Ontdekkingstocht langs plekken en initiatieven in Nederland waar met veel verstand van zaken, een flinke dosis energie en enthousiasme en soms wat lef, gewerkt wordt aan het realiseren van en 'biobased landschap'. Een omgeving waarin beheer, naast natuurwaarden en een fraai landschap, óók energie en interessante producten oplevert

Caracterização agronômica de genótipos de cornichão (Lotus corniculatus L.) Agronomic characterization if birdsfoot trefoil genotypes (Lotus corniculatus L.)

Este trabalho foi conduzido com o objetivo de caracterizar agronomicamente genótipos de cornichão (Lotus corniculatus L.), incluindo oito populações do cv. São Gabriel, um cultivar rizomatoso (cv. ARS-2620) e um cultivar sem rizomas (cv. Trueno). Plantas individuais foram cultivadas e submetidas a sete cortes em condições de campo, durante um ano, em Passo Fundo, Rio Grande do Sul, Brasil. Os genótipos apresentaram variabilidade quanto ao comprimento de entrenós, estatura, diâmetro, comprimento de legumes, produção de forragem e valor nutritivo. Na média geral, as populações e o cv. Trueno foram cerca de 50% mais produtivos em relação ao cv. ARS-2620. Os genótipos apresentaram entre 80 e 100% de sobrevivência. O conteúdo de proteína bruta reduziu de 21,8% (estádio vegetativo) para 11,2% (estádio de frutificação). A média geral de fibra detergente ácido foi de 24,2% e a de fibra detergente neutro variou entre 55,3 e 58,8%.<br>This work was carried out to characterize agronomically birdsfoot trefoil (Lotus corniculatus L.) genotypes, including eight populations derived from the cultivar São Gabriel, one rhizomatous cultivar (ARS-260) and one cultivar without rhizomes (Trueno). Individual plants were submitted to seven cuts under field conditions during one year, at Passo Fundo, Rio Grande do Sul, Brazil. The genotypes showed variability relative to internode lenght, height, diameter, legume lenght, forage production and nutritive value. On the average, the populations and the cv. Trueno were about 50% more productive than the cv. ARS-260. The genotypes presented a survival range from 80% to 100%. The crude protein content decreased from 21.8 (vegetative stage) to 11.2% (fruiting stage). The overall mean for acid detergent fiber was 24.2% and the neutral detergent fiber ranged from 55.3% to 58.8%

Neoantigen-targeted CD8+ T cell responses with PD-1 blockade therapy.

Neoantigens are peptides derived from non-synonymous mutations presented by human leukocyte antigens (HLAs), which are recognized by antitumour T cells &lt;sup&gt;1-14&lt;/sup&gt; . The large HLA allele diversity and limiting clinical samples have restricted the study of the landscape of neoantigen-targeted T cell responses in patients over their treatment course. Here we applied recently developed technologies &lt;sup&gt;15-17&lt;/sup&gt; to capture neoantigen-specific T cells from blood and tumours from patients with metastatic melanoma with or without response to anti-programmed death receptor 1 (PD-1) immunotherapy. We generated personalized libraries of neoantigen-HLA capture reagents to single-cell isolate the T cells and clone their T cell receptors (neoTCRs). Multiple T cells with different neoTCR sequences (T cell clonotypes) recognized a limited number of mutations in samples from seven patients with long-lasting clinical responses. These neoTCR clonotypes were recurrently detected over time in the blood and tumour. Samples from four patients with no response to anti-PD-1 also demonstrated neoantigen-specific T cell responses in the blood and tumour to a restricted number of mutations with lower TCR polyclonality and were not recurrently detected in sequential samples. Reconstitution of the neoTCRs in donor T cells using non-viral CRISPR-Cas9 gene editing demonstrated specific recognition and cytotoxicity to patient-matched melanoma cell lines. Thus, effective anti-PD-1 immunotherapy is associated with the presence of polyclonal CD8 &lt;sup&gt;+&lt;/sup&gt; T cells in the tumour and blood specific for a limited number of immunodominant mutations, which are recurrently recognized over time