Screening and characterization of bean genotypes based on their resistance against Spodoptera frugiperda (Lepidoptera: Noctuidae)

In Brazil, Phaseolus vulgaris L. constitutes one of the main food substrates for human consumption due to its high nutritional features and its affordable cost. Despite the extensive bean production in the country, Spodoptera frugiperda (Lepidoptera: Noctuidae), a polyphagous chewing pest, uses bean plants as alternative hosts, thereby reducing its productivity. The objective of this study was to screen and characterize different bean genotypes for their resistance against S. frugiperda. From 22 genotypes screened on antixenosis experiments, ten genotypes were selected for detailed study on their influence on S. frugiperda biology through antibiosis experiments. The genotypes selected for characterization were IPR Celeiro, IAC Tigre, IAC Nuance, IPR Curió, IAC Una, IAC Sintonia, IAPAR 65, BRS Esplendor, IAC Formoso and IPR Eldorado. For antibiosis analysis, insects since neonates, were kept feeding on leaves during whole larval cycle. The genotype IAC Nuance was the least harmed by S. frugiperda in both free-choice (F₉,₉₀ = 3.96; p < 0.001) and no-choice (F₉,₉₀ = 8.21; p < 0.001) antixenosis tests. In antibiosis tests, the insects fed on the genotype IAC Tigre had the highest mortality rate (F₉,₄₀ = 7.52; p < 0.001). In addition, IAC Nuance negatively influenced the larval weight (F₉,₂₂₉ = 6.59; p < 0.001), larval viability (F₉,₄₀ = 7.52; p < 0.001), pupal period (F₈,₁₁₄ = 4.93; p < 0.001) and total cycle duration (F₈,₉₆ = 4.34; p < 0.001) of S. frugiperda. Finally, using a multivariate clustering analysis, the genotypes were sorted as: Highly resistant- IAC Tigre; Moderately resistant- IAC Nuance; Susceptible- IPR Curió, IAC Una and IPR Celeiro; Highly susceptible- IAC Sintonia, IAPAR 65, BRS Esplendor, IAC-Formoso and IPR Eldorado. This study provides a scientific basis for selecting a genotype that can mitigate the attack of fall armyworm S. frugiperda in bean crops, which can be essential for the integrated pest management (IPM) of this key pest.