Field evaluation of experimental maize hybrids for resistance to the fall armyworm (Lepidoptera: Noctuidae) in a warm temperate climate

Authors: Ni, Xinzhi; HUFFAKER, ALISA - University Of California, San Diego; SCHMELZ, E - University Of California, San Diego; XU, WENWEI - Texas A&M Agrilife; Williams, William; Guo, Baozhu; LI, XIANCHUN - University Of Arizona; HUANG, FANGNENG - Louisiana State University

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/7/2024
Publication Date: 4/19/2024
Citation: Ni, X., Huffaker, A., Schmelz, E.A., Xu, W., Williams, W.P., Guo, B., Li, X., Huang, F. 2024. Field evaluation of experimental maize hybrids for resistance to the fall armyworm (Lepidoptera: Noctuidae) in a warm temperate climate. Insects. 15(4):289. https://doi.org/10.3390/insects15040289.
DOI: https://doi.org/10.3390/insects15040289

Interpretive Summary: Fall armyworm has become an invasive pest worldwide on corn, sorghum and other crops in recent years. To develop new corn germplasm with fall armyworm resistance, and understand the genetic basis of fall armyworm resistance, 12 experimental hybrids (6 sets of reciprocal crosses) with diverse genetic backgrounds were compared with four commercial checks for FAW resistance. The reciprocal cross (an inbred line was used as male and female parent, respectively in a pair of crosses) was used to determine maternal effect of an inbred line on fall armyworm resistance. Fall armyworm resistance was assessed using its damage ratings on artificially infested corn plants, and plant attraction to predators of the fall armyworm larvae. Two reciprocal crosses showed the least FAW injury. A total of 10 predators (five lady beetles and five other predators) were recorded, but predator abundance was not negatively correlated to larval injury by the fall armyworm, and varied greatly between the two years when the study was conducted. In addition, both parents contributed similarly, and no maternal effect on fall armyworm resistance was detected.

Technical Abstract: Polyphagous fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), has become an invasive pest worldwide in recent years. To develop maize germplasm with multiple pest resistance and understand genetic inheritance, twelve hybrids (six pairs of reciprocal crosses) with diverse genetic backgrounds and four commercial checks were examined for FAW resistance in 2013 and 2014. The experiment utilized a randomized complete block design with four replications as the block factor. FAW injury on maize plants was assessed on 7 and 14 d after the artificial infestation at V6 stage, and predatory arthropod taxa and abundance on maize seedlings were recorded 7 d after the infestation. Spodoptera frugiperda resistance varied significantly among the 16 hybrids. Two reciprocal crosses (‘FAW1430’ x ‘Oh43’ and ‘CML333’ x ‘NC358’) showed the least FAW injury. Ten predators (five lady beetles and five other predators) were recorded, and the two most common predators were the pink spotted ladybeetle, Coleomegilla maculata, and the insidious flower (or minute pirate) bug, Orius spp. The predator abundance was not negatively correlated to FAW injury, but varied greatly between 2013 and 2014. Principal component analysis demonstrated that, when compared with FAW resistant (or Bt-transgenic) checks (‘DKC69-71’, ‘DKC67-88’, and ‘P31P42’), five pairs of the reciprocal crosses had moderate FAW resistance, whereas a pair of reciprocal cross (‘NC350’ x ‘NC358’) had high FAW injury rating that is comparable to non-Bt hybrid, ‘DKC69-72.’ Both parents contributed similarly to FAW resistance, and no maternal/cytoplasmic effect of parental inbred lines on was detected.