Performance of sunflower cultivars at different seeding periods in central Brazil.

ABSTRACT: Sunflower (Helianthus annuus L.) is a very important crop for Brazil, and especially for Chapada do Parecis which is the largest domestic producer, because of its climate and soil conditions are adequate to the development of the specie. The performance of cultivars and sunflower seed sowing periods were evaluated in Central Brazil. Experimental design comprised an 8 x 5 factorial randomized complete block, with eight sunflower cultivars (Aguará 06, Aguará 04, MG 305, CF 101, SYN 3950HO, SYN 045, GNZ NEON and HELIO 251) and five decennial seeding periods, with three replicates. Analysis of variance and Scott-Knott´s test (p<0.05) were applied. Cultivars GNZ NEON and SYN 045 provide the highest production rates in achenes, with higher value in favor of GNZ NEON. SYN 3950HO (this with higher value), CF101, MG 305, SYN 045 and Aguará 04 gets the highest oil rates in the achenes, with SYN 045, GNZ NEON, Aguará 04, CF101 and SYN 3950HO with the highest oil production. The first seed sowing period is the most productive and the first and fifth periods have the best results for oil productivity. Cultivar GNZ NEON and the first period exceede the others with regard to vegetative and reproductive variables. RESUMO: O girassol (Helianthus annuus L.) é uma cultura de grande importância para o Brasil, e especialmente para Chapada do Parecis, que é o maior produtor nacional, em virtude das suas condições edafoclimáticas serem propicias ao desenvolvimento da espécie. Objetivou-se avaliar o desempenho de cultivares e épocas de semeadura do girassol no Brasil Central. O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial 8 x 5, sendo oito cultivares de girassol (Aguará 06, Aguará 04, MG 305, CF 101, SYN 3950HO, SYN 045, NEON e HELIO 251) e cinco épocas decendiais de semeadura, com três repetições. Aplicou-se análise de variância e teste Scott-Knott (p