Agronomic performance of interspecific Paspalum hybrids under nitrogen fertilization or mixed with legumes

Nitrogen supply and mixtures with legumes affect agronomic performance of pas- tures, and both practices can guide breeding decisions in Paspalum hybrids. The goals of this study were: (a) quantify herbage accumulation (HA), leaf accumulation (LA), cold tolerance, and N use efficiency (NUE) in P. plicatulum × P. guenoarum hybrids subjected to N fertilization or grown in a mixture with legumes; (b) compare the grass–legume system to a grass–N fertilizer system; and (c) select the best hybrid for future cultivar releases. A randomized complete block design with three repli- cations and a split-plot treatment arrangement was used for 2 yr, with five N rates (0, 60, 120, 240, and 480 kg N ha−1) and a grass–legume mixture [grass + white clover (Trifolium repens L.) + birdsfoot trefoil (Lotus corniculatus L.)] as whole plots, and six genotypes as subplots (hybrids: 1020133, 102069, 103084, 103061; and controls: P. guenoarum ‘Azulão’ and Megathyrsus maximus ‘Aruana’). Higher N rates increased HA, LA, and cold tolerance. Higher NUE was obtained between 60 and 120 kg N ha−1. In the grass–legume mixture HA was similar to the rates of 60 and 120 kg N ha−1. Hybrid 1020133 had HA similar to the controls, LA greater than Aruana, and greater cold tolerance and NUE at 60 kg N ha−1 than Azulão and Aruana. Hybrid 1020133 should be selected for further animal performance stud- ies. The agronomic performance of perennial pastures can be improved through N management, and NUE should be a selection criterion in forage breeding

Evaluation of agronomic performance of alfalfa (Medicago sativa L.) for grazing aptitude in southern Brazil

Este trabalho teve como objetivo avaliar e identificar algumas características morfológicas e a produção de matéria seca (MS) de plantas de alfafa (Medicago sativa L.) selecionadas à aptidão ao pastejo no programa de melhoramento de plantas do DPFA (Departamento de Plantas Forrageiras e Agrometeorologia) da UFRGS e confirmar se as mesmas obtiveram progresso genético em relação a produção forrageira. Foram avaliadas nove populações denominadas: a) Crioula (utilizada como controle), b) São José do Inhacorá (SJI), c) Iara SP, d) E1C3, e) E1C3 Resistente, f) E2C3, g) E1C4, h) E2C4, i) SJI F2. O experimento foi realizado em blocos ao acaso com nove tratamentos representados pelas populações de alfafa, com três repetições. As avaliações foram realizadas através de cortes na linha central da parcela, totalizando uma área útil de 1 metro linear, deixando um resíduo de 10 cm. Antes de cada corte, mensurava-se a altura das plantas. Os dados foram analisados estatisticamente utilizando modelos mistos. Os resultados da caracterização morfológica não diferiram para a variável folha/colmo. Quanto ao número de hastes por planta e ao tipo de haste por planta (basilar ou axilar), o genótipo E1C3 Resistente destacou-se com a maior produção em relação a cultivar Crioula. O genótipo E1C3 obteve o melhor desempenho na distribuição forrageira ao longo das estações do ano, entretanto só conseguiu superar a Crioula na produção de matéria seca total no ano de 2018. O genótipo E2C4 foi o menos promissor. Os demais materiais apresentaram valores intermediários, devendo ser investigados em avaliações futuras, com o objetivo de obter cultivares mais adaptadas às condições do Rio Grande do Sul.The objective of this study was evaluate and identify some morphological characteristics and dry matter production (DM) of selected alfalfa plants for grazing aptitude in the plant improvement program of the DPFA (Department of Forage Plants and Agrometeorology) at UFRGS and confirm whether they have achieved genetic progress in relation to forage production. Nine populations were evaluated: Crioula (used as a control), São José do Inhacorá (SJI), Iara SP, E1C3 Resistant, E1C3, E2C3, E1C4, E2C4, and SJI F2. The experiment was carried out in random blocks with nine treatments represented by the alfalfa populations and three replicates. The evaluations were performed through cuts in the central line of the plot, totaling a useful area of 1 linear meter, leaving a residue of 10 cm. Before each cut, the height of the plants was measured. The data were analyzed statistically using mixed models. The results of the morphological characterization did not differ for the leaf/stem variable. Regarding the number of stems per plant and the type of stem per plant (basilar or axillary), the cultivar E1C3 resistant showed the highest values in relation to the Crioula (control) cultivar. The E1C3 genotype obtained the best performance in the forage distribution throughout the seasons, however it only managed to surpass the Crioula in the production of total dry matter in 2018. The cultivar E2C4 was the least promising. The other materials presented intermediate values, and should be investigated in subsequent evaluations with the objective of obtaining cultivars that are more adapted to the conditions of Rio Grande do Sul

Selection of alfalfa genotypes for resistance to the foliar pathogen Curvularia geniculata

Foliar diseases impose severe restrictions on the persistence and productivity of Medicago sativa, both of which may be increased by developing disease resistant and more competitive genotypes that can improve pasture quality. We found Curvularia geniculata as the principal alfalfa foliar pathogen in the Brazilian state of Rio Grande do Sul (RS). Growth chamber experiments evaluated the resistance of alfalfa genotypes ‘E1C4’, ‘CPPSul’, ‘ABT 805’ and ‘CUF-101’ to C. geniculata as compared the control ‘Crioula’ genotype. These genotypes were also evaluated in field trials at a sea level site in Eldorado do Sul in central RS and at two sites £200 m above sea level, one in Bagé municipality in south west RS and the other at a farm near the town of Alto Feliz in north east RS. Plants were spray-inoculated with 1.6 x 106 ml-1 of C. geniculata spores and visually evaluated for leaf damage 14 days later. The C. geniculata infection rates varied from zero to 100%. Alfalfa persistence and forage mean dry mass (DM) production at the Eldorado site were measured during different seasons from November 2013 to January 2015 by calculating the incidence of invasive plants and morphologically separating leaves from stems and calculating both leaf and stem DM. Data were analysed using mixed statistical models. The best results for persistence and forage DM were shown by the ‘CPPSul’ genotypes (DM = 16,600 kg ha-1) and ‘Crioula’ (DM = 15,750 kg ha-1). These two genotypes will be used for subsequent investigations and selection cycles

Selection of alfalfa genotypes for resistance to the foliar pathogen Curvularia geniculata

Foliar diseases impose severe restrictions on the persistence and productivity of Medicago sativa, both of which may be increased by developing disease resistant and more competitive genotypes that can improve pasture quality. We found Curvularia geniculata as the principal alfalfa foliar pathogen in the Brazilian state of Rio Grande do Sul (RS). Growth chamber experiments evaluated the resistance of alfalfa genotypes ‘E1C4’, ‘CPPSul’, ‘ABT 805’ and ‘CUF-101’ to C. geniculata as compared the control ‘Crioula’ genotype. These genotypes were also evaluated in field trials at a sea level site in Eldorado do Sul in central RS and at two sites £200 m above sea level, one in Bagé municipality in south west RS and the other at a farm near the town of Alto Feliz in north east RS. Plants were spray-inoculated with 1.6 x 106 ml-1 of C. geniculata spores and visually evaluated for leaf damage 14 days later. The C. geniculata infection rates varied from zero to 100%. Alfalfa persistence and forage mean dry mass (DM) production at the Eldorado site were measured during different seasons from November 2013 to January 2015 by calculating the incidence of invasive plants and morphologically separating leaves from stems and calculating both leaf and stem DM. Data were analysed using mixed statistical models. The best results for persistence and forage DM were shown by the ‘CPPSul’ genotypes (DM = 16,600 kg ha-1) and ‘Crioula’ (DM = 15,750 kg ha-1). These two genotypes will be used for subsequent investigations and selection cycles

Evaluation of severity of Curvularia geniculata on Midicago sativa cv. Crioula in Southern Brazil

Póster presentado en el XXI Reunión de la Sociedad Española de Fisiología Vegetal y el XIV Congreso Hispano-Luso Fisiología Vegetal, celebrado en Toledo del 14 al 17 de junio de 2015.Peer Reviewe