Physiological Basis of Fall Armyworm (Lepidoptera: Noctuidae) Resistance in Seedlings of Maize Inbred Lines with Varying Levels of Silk Maysin
Abstract
To assess both foliage- and ear-feeding insect resistance in the same maize inbred lines, fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistance at the seedling stage was examined in 6 corn inbred lines, including 4 CIMMYT maize inbred lines (CML333, CML335, CML 336, and CML338) with varying levels of silk maysin that confers corn earworm, Helicoverpa zea (Boddie), resistance and controls (fall armyworm-resistant Mp708 and susceptible AB24E). Fall armyworm injury rating and chlorophyll content were examined under greenhouse and field conditions. Plant height, plant stem circumference, and photosynthesis-related measurements were recorded on uninfested and infested plants only under greenhouse conditions. Injury ratings on CML333, CML336, and CML338 (with a range of low to high levels of silk maysin) were the same as for the resistant control (Mp708), and were significantly lower than for the susceptible control AB24E and CML335 (without silk maysin). Plant height, plant stem circumference, and chlorophyll content varied among the 6 inbred lines, but were not consistently correlated to resistance at the seedling stage. Photosynthetic rate was negatively affected by injury in AB24E, CML333, CML335, and CML336, but not affected in CML338 and Mp708. The reduction in photosynthetic rate of fall armyworm-susceptible AB24E, and in resistant CML333 and CML336 indicated that insect resistance in CML333 and CML336 might not be related to photosynthetic rate. At the same time, the data suggest that CML338 and Mp708 were tolerant to herbivory because no difference in either photosynthetic rate or photosynthetic capacity was detected in either inbred line between uninfested and injured corn seedlings. Further examination of photosynthetic capacity based on A/Ci and light response curves supported this resistance mechanism categorization. This experiment indicated that corn earworm-resistant corn inbred lines with varying levels of silk maysin could confer resistance to foliage-feeding fall armyworm at its seedling stage.View this article in BioOne
Downloads
Published
Issue
Section
License
Copyright for any article published in Florida Entomologist is held by the author(s) of the article. Florida Entomologist is an open access journal. Florida Entomologist follows terms of the Creative Commons, Attribution Non-Commercial License (cc by-nc). By submitting and publishing articles in Florida Entomologist, authors grant the FOJ and Florida Entomologist's host institutions permission to make the article available through Internet posting and electronic dissemination, and to otherwise archive the information contained both electronically and in a hard printed version. When used, information and images obtained from articles must be referenced and cited appropriately. Articles may be reproduced for personal, educational, or archival purposes, or any non-commercial use. Permission should be sought from the author(s) for multiple, non-commercial reproduction. Written permission from the author(s) is required for any commercial reproduction.
