REAÇÃO DE HÍBRIDOS DE GIRASSOL AO Pratylenchus brachyurus

Abstract

Sunflower (*Helianthus annuus* L.) cultivation stands out as a strategic alternative for the second crop season in the Cerrado region; however, the occurrence of the root-lesion nematode (*Pratylenchus brachyurus*) can limit its development. Given this, the objective was to evaluate the reaction of three sunflower hybrids (Hélio 250, Hélio 251, and Tera 204 CLDM) to *P. brachyurus* parasitism. The experiment was conducted in a greenhouse at IF Goiano – Hidrolândia Campus, using a completely randomized design with seven replicates. At 15 days after sowing (DAS), each plant—grown in 500 mL cups containing autoclaved soil—was inoculated with 200 specimens of *P. brachyurus*. At 69 DAS, the fresh mass of the shoot system (P.A.) and root system (P.Raiz), as well as the nematode population density per 10 g of root (Nema/10g), were determined. All evaluated hybrids behaved as poor hosts, demonstrating potential for reducing the pathogen population in the soil. The Hélio 251 hybrid exhibited the lowest reproduction rate, followed by Hélio 250. The Tera 204 CLDM hybrid showed the highest reproduction factor, differing significantly from the others according to the Scott-Knott test (p < 0.05), which indicates greater relative susceptibility for this material. It is concluded that the evaluated hybrids are viable options for crop rotation or succession systems in areas infested with *P. brachyurus*, with the Hélio 250 and Hélio 251 materials standing out due to lower nematode multiplication.