Morphological and Biochemical Resistance to Spodoptera frugiperda (J.E. Smith) in Maize Inbreds

Twenty maize in breds were evaluated under natural fall armyworm (FAW) infestation at ANGRAU, Lam, Guntur, during the lateKharif2024–25 season to identify lines combining high yield with FAW tolerance. Performance of the studied genotypes revealed the presence of varying degrees of FAW damage ratings, indicating the presence of FAW tolerant genotypes. Correlation analysis showed negative association between FAW infestation and secondary metabolite levels. The multi‐trait genotype–ideotype distance index (MGIDI) was applied at 25% selection intensity to rank genotypes against an ideo type defined by high yield, low FAW damage, and elevated defense traits. Five in breds (PL 22389, PL 22339, LM14, PL 22373, PL 23150) achieved MGIDI scores closest to the ideotype, with desirable selection differentials in FAW damage score (–27.5%), total soluble sugars (–22.5%), and positive gains in grain yield (23.1%), tannin content (24.0%), trichome density (20.8%), and phenol content (15.9%). These tolerant lines represent valuable genetic resources for sustainable FAW management and could reduce reliance on chemical control.