Abstract

In soybean, stink bugs are considered the most important pest insect as they feed directly from the grain, causing significant losses in seed yield and quality. The use of resistant genotypes is a promising strategy to control these insects. Focusing on selection of soybean lines with resistance and high yield potential, 251 recombinant inbred lines ( RIL s), derived from a cross between IAC ‐100 (resistant) and CD ‐215 (susceptible), were evaluated in two experiments, designed as alpha‐lattice, with three replicates in Piracicaba, during the growing seasons of 2012/13 and 2013/14. The evaluated traits were as follows: number of days to maturity ( NDM ), plant height at maturity ( PHM ), grain filling period ( GFP ), lodging (L), agronomic value ( AV ), grain yield ( GY ), weight of a hundred seeds ( WHS ), leaf retention ( LR ), and healthy seeds weight ( HSW ). Variance components were estimated by the Restricted Maximum Likelihood method ( REML ). Heritability and selection gain ( SG ) parameters were also calculated. Selection was carried out based on 2012/13 season, considering the genotypes that exhibited a minimum HSW of 2908.26 kg ha⁻¹ (acceptable losses of 20% from the average GY ). Insect population was monitored by cloth beating. An increase in stink bug population was observed during the grain filling period, with the highest population density occurring in the season 2012/13. Estimates of the variance components demonstrated the elevate influence of the interaction genotype x environment on GY and HSW , which exhibited the lowest estimates of heritability (23 and 34%, respectively). The estimate selection gain, calculated from the predicted means of GY and HSW , was of 665.4 and 482.4 kg ha⁻¹ season 2012/13. Therefore, the applied selection allowed the identification of the genotypes exhibiting higher yields and resistance to the stink bug complex. From the RIL population, lines or genotypes potentially useful to generate novel cultivars were identified.

Stink bugs are considered key pests of soybean, because they feed directly on reproductive parts of the plant, causing damage to the seeds and pods. In Brazil, the damage is caused by three main species, Nezara viridula , Piezodorus guildinii and Euschistus heros . To avoid substantial economic losses, chemical control is widely used. However, this method cause impact to the environment; cases of insect resistance to insecticides have been identified, some active ingredients were banned in Brazil and there is no prevision to launch new insecticides. In this scenario, the development of soybean cultivars with resistance to stink bug is really important to maintain or grow the soybean yield with sustainability.