Caracterização morfológica, agronômica e divergência genética para caracteres germinativos de diferentes genótipos de girassol

Abstract

The sunflower (Helianthus annuus L.) is an annual, robust and tolerant to drought that produces flowers in spring and summer, but can bloom all year plant. Currently, the sunflower is gaining prominence in the national and international scene because it is a plant that has multiple uses which almost everything is useful. Among the crops planted in the Brazilian Northeast sunflower is one of presenting economic viability for the region showing lower financial market risk. Given the above, this study aimed to characterize different sunflower genotypes derived from the germplasm bank of the Agricultural Research Enterprise (IPA), Northeast Brazil. The works were carried out between the months of september 2013 to june 2014, being developed in the field of experimental Experimental Station belonging to the IPA, in Vitória de Santo Antão (PE), and the Seed Laboratory of the Department of Agronomy, University Federal Rural de Pernambuco. In the laboratory, the characters were evaluated: characterization of the seed (achenes) and sunflower seedlings; Seed morphology (achenes); germination and seedling morphology; establishment of criteria for defining categories of normal and abnormal seedlings; genetic divergence for germination characters of sunflower. Genotypes were: Sunflower Black, Crioulo, BRS 323, BRS 324, Hélio 251, Embrapa 122 and Aguará 04. For the laboratory experiment, the design was completely randomized design with seven treatments (genotypes) and four replicates of 25 seeds each. As for the field experiment were used varieties: Criollo, BRS 323, Black Sunflower, Aguará 04, BRS 324, where the morphological characterization was performed; evaluation of agronomic and yield components of sunflower, with experimental design in randomized blocks with five treatments (genotypes) and six replications. The seeds of sunflower against the seven genotypes as the shape, size, weight and color can be different. Germination is epigeal and fanerocotiledonar starting on the first day and ending on the seventh day after sowing, for the seven genotypes. The intensity of staining for hypocotyl anthocyanins, green color of the cotyledons and the serrated margins of protophilus are descriptors that differentiate the genotypes studied. The descriptors allow the distinction of some morphological characters among the five sunflower genotypes evaluated in the field. The five sunflower genotypes have high productivity especially for genotype BRS 323 at the lower production cycle. Characters final stand, physiological maturity and plant height are the main determinants of variations in productivity. Germ characters that contribute most to divergence are: germination and emergence percentage. The most similar genotypes are Aguará 04 and Black Sunflower, whereas the genetically more distant are the BRS 323 and Embrapa 122 genotypes.