Quality of sunflower seeds in function of thickness classification and sowing under speed variation of the seeder-fertilizer¹

ABSTRACT

The objective was to evaluate the quality of sunflower seeds classified according to their thickness and passed through the seeder-fertilizer dosing system under variation of the travel speed. A lot of M734 was classified by thickness passing the seeds through a set of oblong-hole sieves and two thicknesses were selected. A portion of the seeds with only the commercial classification was also reserved, named as non-classified. The biometric evaluation was done and the sowing was carried out at 5.0, 6.5, 8.0, 9.5 and 11.0 km h^-1. The quality of the seeds was evaluated through: germination and first germination count, average time and percentage of emergence in sand, accelerated aging and tetrazolium test. The classification by thickness reduce the coefficient of variation of the length, width, thickness, and mass but seeds classification does not affect seed vigor and viability after sowing under speed variation. In the higher studied speed, the passage of seeds through the dosing mechanism reduces germination. The vigor is affected at 6.5 km h^-1 speed by the accelerated aging test. According to the emergence in sand and tetrazolium test, speed variation does not affect the vigor and viability of sunflower seeds.

Keywords
biometry; Helianthus annuus L.; mechanical damage; sowing damage