Crescimento e desenvolvimento da cultura do girassol no Recôncavo da Bahia

Abstract

The objective of this work was to evaluate through the growth analysis the vegetative and productive performance of the sunflower (Helianthus annuus L.), at different times of sowing and plant populations for region of the Bahian Recôncavo. The works had been carried through in the experimental area of the Bahian Agricultural Development Company S A (EBDA), in Conceição of the Almeida/BA, South Recôncavo and in the Federal Institute of Education, Science and Technology - Catu Campus, in Catu/BA, Recôncavo North, at two times of sowing: the first time (september to december/2008), second time (june to september/2009). For each experiment we used the randomized block design with four treatments and four repetitions. The treatments were: T1 (35,000 plants ha-1), T2 (45,000 plants ha-1), T3 (55,000 plants ha-1) and T4 (75,000 plants ha-1). Had been used parcels of 5,00 m of length and 7,20 m of width, constituted of eight lines each, being three borders, three destined to the data of income and two the analysis of growth, that they had been destructive, and in which if they had effected biweekly collections of 10 plants for parcel, from 21 days after the emergency until the end of the cycle, for determination of the characteristics agronomics (height of plants, total leaf number and diameter of the connecting rod), mass of the dry substance and the foliar area of the plant. By occasion of the physiological maturity (R9) they had been evaluated the diameter of chapters, the mass of 1000 achenes and the index of harvest, determined for the relation between the accumulated total dry mass of finishes collection and of the productivity of achenes and the mass of achenes of the useful parcel for determination of the productivity (kg ha-1), with the correction of the humidity for 13%. One concluded that: a) The time of sowing, the plant populations and the locality influence in the cycle of cultivating, the increment of the foliar area and in the accumulation of total dry substance, detaching the population of 75.000 plants ha-1; b) The physiological indices are efficient to identify differences in the growth of plants of the sunflower, being able to more indicate the time of more favorable sowing and the plant populations adjusted to express its productive potential; c) The times of sowing and the plant populations proposals can have negative been influenced for the low rainfall index verified in the two localities, providing low productivity the praised ones to cultivate studied it.