Characteristics of sunflower in function of sowing dates in northwest region of Rio Grande do Sul, Brazil/Caracteristicas de plantas de girassol, em funcao da epoca de semeadura, na Regiao Noroeste do Rio Grande do Sul

• Published in: Ciência rural Vol. 42; no. 10; p. 1738
• Main Authors: Cadorin, Antonio Mauro Rodrigues, de Souza, Velci Queiroz, Manfron, Paulo Augusto, Caron, Braulio Otomar, Medeiros, Sandro Luis Petter
• Format: Journal Article
• Language: Spanish
• Published: Universidade Federal de Santa Maria 01.10.2012
• ISSN: 0103-8478; 1678-4596

Based on the importance of production of sunflower (Helianthus annuus L.) in Brazil the aim of this study was to evaluate the influence of the environment of cultivation and sowing date on morphological (plant height and chapter size) and crop production (grain yield and one thousand achene weight) characteristics of sunflower. The genotypes used in this stduty were Helio 250, 251, 358, 884 and 885 during the 2008-09 growing season and the Helio 250, 251, 253, 360, HLA211 and Paraiso 33 in the 2009-1 0 growing season, cultivated in three sowing dates (august, october and december). The experiment was conducted in randomized block design with four replications in Frederico Westphalen in Northwestern of the Rio Grande do Sul, Brazil. Analyses were individual fitness and joint variance, whereas for the comparison of averages of the estimates was applied the Tukey test at 5% level of probability. The genetic constitutions do not revealed differences in grain yield, only the plant height is influenced by the environment and sowing dates. The capitulum size is influenced by environment and achene yield responds positively in favorable environmental conditions and sowing date, with increments near 600kg [ha.sup.-1], while reducing the one thousand achene weight with advancing sowing date.