TIPOS DE RESISTÊNCIAS EM GENÓTIPOS DE SOJA A Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae)

Abstract

Among the factors that contribute to reduce the productivity of soybean crops, Diabrotica speciosa damages the plants in almost all its development. The management of this pest is complex, since the insect presents a polyphagous feeding habit, besides the adults possess great dispersion capacity. The development and use of insect resistant genotypes is a desirable tool in the management of D. speciosa. The objective of this work was to evaluate antixenose resistance for feeding and oviposition for adults of D. speciosa and tolerance for D. speciosa larvae in 20 soybean genotypes. For the conduction of the tests, a completely randomized design was used. It was evaluated the attractiveness, leaf area index (LAI) and number of trichomes (antixose or non-preference for feeding), number of eggs and color measurement (antixose or non-preference for oviposition), chlorophyll content at 15 days after infestation (DAI), root dry mass, weight and number of recovered larvae (tolerance). Genotypes PI 227682, PI 227687, IAC 100, BRS 7525, BRS 8170 and M 7739 were less attractive and consumed. In contrast, the genotypes Dowling, BRS 7270, NS 7338, BMX Power, BRS 7470, BRS 8082 and BRS 284 were the most attractive and consumed. The genotypes NS 7338, Power BMX, BRS 7470, M 7110 and BRS 8082 were preferred for oviposition with higher egg numbers. In the tolerance test, there were no significant differences in larval weight, genotypes M 7739 and M 7110 showed higher numbers of larvae, and the genotypes BMX Power, BRS 284, M 7110, BRS 7170, BRS 7270, BRS 7525, IAC 100 and NA 5909 showed the highest root masses. Commercial genotypes BRS 7525, BRS 8170, M 7739, BRS 7170, BRS 7270, NA 5909 and NS 7209 present features that can be used by breeders to develop resistant cultivars, and by producers in the MIP.