Selection of popcorn genotypes tolerant to Spodoptera frugiperda and key traits related to the identification of tolerance

The Spodoptera frugiperda, is one of the most deleterious pests of popcorn and the identification of tolerant genotypes is determinant in breeding programs. The objective of this study was to select popcorn genotypes tolerant to S. frugiperda and the key traits related to the identification of tolerance. The popcorn varieties UEM J1, Composto Marcia, Arachida, Composto Gaucho and Zapalote Chico (resistant check) were evaluated in a completely randomized design with 100 replications. The experimental unit consisted of one Petri dish, containing plant material and a larva. The following traits were evaluated: larval stage duration (LSt), food intake weight (IW), final larva weight (FW), mean larva weight (MW), feces (F), assimilated (A) and metabolized food weight (M), relative consumption rate (RCR), relative metabolic rate (RMR), relative growth rate (RGR), conversion efficiency of ingested food (CEI), apparent digestibility (AD), conversion efficiency of digested food (CED) and leaf area consumed (LAC). The diagnosis of multicollinearity, analysis of canonical variables, genetic divergence, hierarchical clustering, factor analysis and canonical correspondence analysis were carried out to perform multivariate analysis. After the multicollinearity test, the traits FW, IW, RCR, AD and LAC were maintained for further analysis. Variety Arachida was considered tolerant to S. frugiperda and can be used in the future as a source of favorable alleles to breed tolerant popcorn hybrids. The traits relative consumption rate, apparent digestibility and leaf area consumed were considered key traits in the identification of tolerance against S. frugiperda in popcorn genotypes.