Evaluating founding landraces of maize population PI 674097 for resistance to leaf-feeding Spodoptera frugiperda

Authors: Abel, Craig; FREI, URSULA - Iowa State University; Woolfolk, Sandra

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2023
Publication Date: 4/11/2023
Citation: Abel, C.A., Frei, U.K., Woolfolk, S.W. 2023. Evaluating founding landraces of maize population PI 674097 for resistance to leaf-feeding Spodoptera frugiperda. Southwestern Entomologist. 48(1):83-88. https://doi.org/10.3958/059.048.0108.
DOI: https://doi.org/10.3958/059.048.0108

Interpretive Summary: Maize population PI 674097 is of interest to breeders for yield improvement of the crop. While growing PI 674097 in Puerto Rico under heavy natural infestations of fall armyworm, breeders observed this genotype was less damaged than other maize genotypes growing in the same field. The objective of this study was to evaluate PI 674097, and the parents of this population, for resistance to fall armyworm leaf feeding. In 2021 and 2022, maize entries were grown in the field and artificially infested at the seven/eight-leaf stage. Leaf-feeding damage was visually scored at 7 and 14 days post infestation with fall armyworm. All scores for NSL 283507, PI 498583, PI 583912, and PI 674097 were lower (i.e. more resistant) than the susceptible check, GEMN-0131. In 2022, 14-day scores for PI 674097 were not different from the resistant check, Mp708. Throughout the study, it was observed that PI 674097 was variable in its response to fall armyworm leaf feeding with individual plants receiving a range of 14-day scores from 2 (resistant) to 7 (susceptible). This variability may be useful for breeders when selecting for high levels of resistance to the fall armyworm.

Technical Abstract: A pest of maize (Zea mays L.) native to the Americas, the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a recent invasive pest of Africa, Asia, and Oceania. Resistant to several classes of insecticides and some Bt-maize toxins, the insect causes economic damage to maize by feeding on leaf, tassel, and ear tissues. Using native resistance in maize along with existing tactics could improve control. The objective for the study was to evaluate resistance to leaf-feeding fall armyworm in maize gerplasm PI 674097 and the parents used to develop this population. Plants grown in the field and artificially infested at the seven/eight-leaf stage were visually scored for leaf-feeding damage at 7 and 14 days post infestation. All scores for NSL 283507, PI 498583, PI 583912, and PI 674097 were lower (i.e. more resistant) than the susceptible check, GEMN-0131. In 2022, 14-day scores for PI 674097 were not different from the resistant check, Mp708 (3.6 ± 0.5 and 2.7 ± 0.5, respectively). PI 674097 was variable in its response to fall armyworm leaf feeding with individual plants receiving a range of 14-day scores from 2 (resistant) to 7 (susceptible) across both years of testing. This variability may be useful when selecting for higher levels of resistance to the pest.