Identification of soybean promising lines resistant to pod-sucking bug, Riptortus linearis (Fabricius)

Abstract

Pod-sucking bug Riptortus linearis (Fabricius) is the most destructive soybean insect pest in Indonesia. The losses caused by this insect could reach 2–100%. This study aimed to determine the resistance level of 13 soybean lines to pod-sucking pests using no choice and free choice tests. The evaluation for resistance to the pod-sucking bug was performed using free-choice test (FCT) and no-choice test (NCT) methods. In FCT, all genotypes were placed in a meshed cage, meanwhile, in the NCT, each soybean genotype was individually placed in a meshed cage. Newly emerged adults R. linearis (n = 2 per plant) were infested during the R5 stage of the soybean. In the FCT, the range of pod damage intensity was 11.03–44.22% (average of 24.68%). Meanwhile, the seed damage intensity was ranged from 10.94–41.14% (average of 20.93%). In the NCT, the range of pod and seed damage intensities was 18.89–47.52% (average of 37.17%) and 13.19–72.38% (average of 37.74%), respectively. One genotype (G4) was identified as resistant based on the pod and seed damage in the FCT and NCT, respectively. Soybean genotypes that were consistently resistant based on the pod and seed damage in the NCT, as well as FCT methods, could potentially be used as gene sources for breeding soybean resistance to pod-sucking bug. The NCT method provides higher damage intensity than that of the FCT method. Thus, the NCT method could be used to screen soybean genotypes for resistance against pod-sucking bug to obtain genotypes with higher resistance level.