The performance of 35 soybean germplasms including 16 cultivars, 6 plant introductions and 13 lines derived from the soybean improvement program against stink bugs, was evaluated for two consecutive years, 1983/1984 and 1984/1985, in relation to the stink bugs (Hemiptera, Pentatomidae) species Piezodorus guildinii (Westwood), Euschistus heros (F.) and Nezara viridula (L.). The two experiments were conducted under field conditions at the Experimental Center of Instituto Agronômico located in Campinas, State of São Paulo, Brazil. A complete randomized block design with 35 treatments and 4 replications was used. The individual plot was a single row 2 meters long. Artificial infestations with adults were made to supplement the natural field infestation of stink bugs. The infestation level was moderate in the first year and severe in the second. Three criteria were used to judge the resistance to stink bugs: the percentual index of pod damage, the percentage of foliar retention after pod maturation and yield. The percentual index of pod damage is given by the formula 1/2 (% of pods with intermediate damage) + % of pods completely damaged. The percentage of foliar retention was visually estimated upon maturation of the pods. The cultivar Paraná was the most susceptible treatment being recommended for use as a susceptible check for stink bugs. The lines IAC80-4228 and IAC80-598-2-4, obtained through the soybean breeding program for resistance to stink bugs, had good performance. They still present however some undesirable agronomic features and cannot be recommended for distribution to the farmers.
soybean; Glycine max (L.) Merrill; stink bugs; Pentatomidae; plant resistance; Piezodorus guildinii. (Westwood); Nezara viridula (L.); Euschistusheros (F.)