Sowing seasons of second crop sunflower after maize, in no-tillage system in the Cerrado region of Tocantins, Brazil

Abstract

The sunflower (Helianthus annuus L.) is traditionally considered as a culture of great plasticity. It presents important agronomic characteristics, like tolerance to drought, to cold and heat. In that context the culture becomes favorable to the second crop, together with the use of the no-tillage. The objective of this study was to evaluate the performance of sunflower cultivars in four times of no-tillage on maize straw in second crop 2009, in the South part of the State of Tocantins. The experimental design was randomized blocks with 20 treatments and three repetitions. Treatments were arranged in a 4 x 5 factorial, four times: EP1(03/15/2009); EP2(28/3/2009); EP3(04/09/2009) and EP4(01/05/2009) with five cultivars: H250, H251, H358, H360 e H884, on straw maize. There was reduction in all the evaluated characteristics with retardation of the sowing, except for hectolitre weight.Highest productivity was obtained in the times of sowing in march and april. The cultivar H884 had the best performance for most of the analyzed variables.