Agronomic characterization of sunflower cultivars for animal feeding in tropical conditions

This study was developed to examine morpho-agronomic traits of 18 sunflower cultivars and identify superior cultivars in terms of grain yield, forage quality, or both, for animal feeding. Twenty-two morpho-agronomic traits related to plant development and architecture; earliness of maturity; grain yield (achenes); dry matter yield; and dry matter content were evaluated. Cultivars Hélio 253, Hélio 358, Embrapa 122, BRS 321, and Hélio 360 showed inflorescence at the final stage. Aguará 4 showed the lowest flowering rate, characterizing it as late-maturing. For grain yield, cultivars Charrua, Olisun 3, BRS 321, Paraíso 103CL, Paraíso 65, Aguará 6, and CF 101 are recommended, as they showed the highest achene yields (average: 1,541.67 to 2,148.81 kg.ha−1, respectively). Cultivars Charrua, Hélio 251, Olisun 3, Hélio 360, Paraíso 55, and Paraíso 103CL exhibited higher dry matter yields (9,550.93 to 11,789.91 kg ha−1) and were thus indicated for forage production. Cultivars Charrua, Olisun 3, BRS 321, Paraíso 103CL, Paraíso 65, Aguará 6, and CF 101 are recommended for grain yield, for the diet of monogastric animals; Charrua, Hélio 251, Olisun 3, Hélio 360, Paraíso 55, and Paraíso 103CL for forage yield, for ruminant feeding; and Charrua, Olisun 3, and Paraíso 103CL for both purposes.

Biomass turnover in brachiaria cultivars in a tropical environment / Fluxo de biomassa em cultivares de brachiaria em ambiente tropical

The experiment was conducted to evaluate the morphogenetic traits of three Brachiaria cultivars (common, Llanero and Tupi) subjected to continuous grazing with variable stocking rate in the four seasons of the year. A randomized block design with five replicates was adopted. Tissue turnover evaluations were carried out in the summer, fall, winter and spring, with measurements taken every two days. Stem length and the length of each green leaf were measured. With these determinations, the following variables were calculated: stem elongation rate (cm/tiller/day), leaf elongation rate (cm/leaf/day), number of live leaves per tiller and phyllochron (days/leaf). The highest leaf appearance rate was obtained by Tupi grass in the summer, and the lowest by Llanero grass in the winter. The lowest phyllochron, 5.90 days/leaf, was obtained by Tupi grass in the winter, whereas in commercial cultivars Llanero and common the average phyllochron was 9.04 and 10.04 days/leaf, respectively. Because of the effect of the transition from the dry season to the beginning of rains in the summer, this was the period of greatest variations in results among the different cultivars. Llanero grass stood out for the highest values for plant, tiller and leaf lengths, resulting from greater stem and leaf elongation rates. Tupi grass had the worst performance of all cultivars.

O experimento foi realizado com o objetivo de avaliar as características morfogenéticas de três cultivares de Brachiaria humidicola (common, Llanero e Tupi), submetido a pastejo contínuo, em quatro estações do ano. Foi utilizado delineamento em blocos casualizados, com cinco repetições. As avaliações do volume de tecido vegetal foram realizadas no verão, outono, inverno e primavera, e as medidas foram tomadas a cada dois dias. Determinaram-se o comprimento da haste e o comprimento de cada lâmina de folha verde. Com essas determinações, foram calculados: taxa de alongamento (cm / perfilho / dia), taxa de alongamento foliar (cm / folha / dia), número de folhas vivas por perfilho e filocromo (dia / folha). A maior taxa de aparecimento de folhas foi obtida na grama Tupi no período de verão, e o menor aparecimento ocorreu no cultivar Llanero, durante o inverno. O menor filocromo (5,90 dias / folha) foi verificado no cultivar Tupi, no inverno, enquanto no cultivares Llanero e common o filocromo médio foi de 9,04 e 10,04 dias / folha, respectivamente. Devido ao efeito da transição, a partir da estação seca para o início das chuvas no verão, foi constatado que as maiores variações nos resultados dos diferentes cultivares, ocorreram nesta época. O cultivar, Llanero se destacou para os maiores valores da planta, resultante das maiores taxas de alongamento de caule e folhas. O cultivar Tupi teve o menor desempenho em comparação com os outros.