Screening for host plant resistance to fall armyworm (Spodoptera frugiperda) in selected sorghum (Sorghum bicolor) breeding lines using detached leaf assay in Kenya

Fall armyworm (FAW) causes significant damage in sorghum globally. Sixteen Sorghum genotypes were evaluated for resistance to FAW using a detached leaf bioassay in the laboratory at Egerton University and the greenhouse at Kenya Agriculture and Livestock Research Organization, Njoro, in 2020. The experiment was laid out in a completely randomized design with three replications. Data on larval survival, weight, pupation, pupal weight, and adult emergence were collected and analyzed using SAS version 9.2, with means separated using LSD at p≤0.05. The results indicate that genotypes significantly influenced larval weight, pupation, pupal weight, and adult emergence but did not influence larval survival. Larval weight ranged between 15 and 35.75 mg, while pupae weighed between 0.04 and 0.17 mg. Pupation rate ranged between 25 and 90%, and adult emergence ranged between 27 and 89.7%. Larval weight positively and significantly correlated with pupation, adult emergence, and larval survival. Genotypes GBK 000446, IS 21055, GBK 000121, GBK 000392, and IESV 92022/1-SH had low larval survival and weight, pupation rate, pupal weight, and adult emergence rate. This indicates that they could be resistant to FAW, and the mechanism of resistance is required to validate the host plant resistance for the five genotypes. Key words: Fall army worm, host plant resistance, screening, sorghum.