Role of Maize Silk in Host Plant Resistance to Fall Armyworm: Evidence from Survival and Developmental Bioassays

Abstract

Maize (Zea mays L.) is a globally important cereal crop whose productivity is severely constrained by fall armyworm (FAW) (Spodoptera frugiperda J.E. Smith), a destructive and invasive pest. Host plant resistance offers an eco-friendly and sustainable approach for its management, and antibiosis plays a crucial role by adversely affecting insect growth and reproduction. The present study evaluated the antibiosis component of resistance in selected maize genotypes at the R3 stage (silking) under controlled laboratory conditions. Silk tissues collected 10–12 days after silking were offered to neonate larvae, and their effects on survival and development were assessed by recording larval survival percentage, larval weight and duration, pupation percentage, pupal weight and duration, adult emergence, adult longevity, and fecundity. Significant differences were observed among the genotypes, reflecting variability in their resistance responses. Resistant genotypes (MIL 9-1230, MIL 9-1309, MIL 9-1308) (R) exhibited reduced larval survival, prolonged development, lighter larval and pupal weights, and lower adult emergence and fecundity, indicating strong antibiosis effects. Moderately resistant genotypes (MIL 9-1179, MIL 9-1260) (MR) expressed intermediate levels of resistance, while susceptible genotypes (Sarhad HSRB, VS 144) supported higher larval survival, rapid development, heavier pupae, and greater fecundity. These results clearly demonstrate that silk tissues play an important role in mediating resistance and that genotypic variation exists in antibiosis expression against FAW. The identification of resistant and moderately resistant genotypes provides valuable sources for breeding programs aimed at developing cultivars with durable resistance, thereby contributing to sustainable management of this invasive pest.