Resistance in diverse maize genotypes to invasive fall armyworm Spodoptera frugiperda (J. E. Smith) reveals potential morpho-biochemical traits

Fall armyworm, Spodoptera frugiperda (J. E. Smith) is a major invasive insect pest of maize causing severe economic losses in all major maize-growing countries. Host-plant resistance is one of the key tactics for reducing the losses caused by this pest. In the present study, maize genotypes were screened under artificial infestation to identify resistant sources to FAW and determined the pivotal morpho-biochemical traits associated with resistance. The findings revealed that four maize genotypes, namely CML 67, DMRE 63, CML 72, and CML 141, exhibited resistance to FAW. Furthermore, several morpho-biochemical traits were identified as influential factors in conferring resistance. Trichome density, leaf thickness, cob characteristics viz., cob length, cob width, husk parameters viz., husk length, husk width, number of husk layers, husk weight, and husk tightness, and yield parameters demonstrated negative correlations with leaf damage rating among the various maize genotypes. On the other hand, leaf morphology including leaf length, leaf width and plant architecture such as plant height, number of nodes per plant, and internodal distance exhibited positive correlations with leaf damage rating. Nitrogen, phosphorous, protein, total soluble sugars, and amino acids were positively correlated with leaf damage rating, while potassium, acid detergent fiber, acid detergent lignin, total phenol, and total tannin contents exhibited negative correlations. These results suggest that certain traits, including trichome density, leaf thickness, cob characteristics, husk parameters, and biochemical traits significantly contribute resistance to fall armyworm in maize. Importantly, this research is expected to facilitate the selection of FAW-resistant lines for integration into maize breeding programs, thereby contributing to sustainable maize production.