Location: Crop Germplasm ResearchTitle: Genetic mapping of fall armyworm resistance in Zoysiagrass) Author
Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/15/2011
Publication Date: 6/27/2011
Citation: Jessup, R., Renganayaki, K., Reinert, J., Genovesi, A., Engelke, M., Paterson, A., Kamps, T., Schulze, S., Howard, A., Giliberto, B., Burson, B.L. 2011. Genetic mapping of fall armyworm resistance in Zoysiagrass. Crop Science. 51:1774-1783. Interpretive Summary: Zoysiagrass is a low-growing rhizomatous and stoloniferous grass that forms a dense sod and is used as a turfgrass. Even though it is a warm-season grass, it is very cold-tolerant and it is grown in the United States along the Atlantic coast from New England to Florida and west to Texas and in California. As is the case with most turfgrasses, zoysiagrass is susceptible to several disease and insect pests. One insect that can be a serious problem is the fall armyworm, and it is one of the most damaging insects on turfgrass in the southeastern U.S. This study was conducted to investigate the resistance to this insect in zoysiagrass. Hybrid plants from crosses between resistant and susceptible plants of zoysiagrass were used for this study. Using molecular markers, we were able to develop a genetic map of the grass, and most importantly we were able to find two markers close to and on both sides of the gene that controls resistance to the fall armyworm. Plant breeders can use these markers to identify susceptible and resistant plants without having to feed leaf tissue from each plant to these insects to determine if they are resistant or susceptible to insect. Feeding tests are not always that reliable. These findings are very important because using these markers can save valuable time, and it allows the breeder to be more efficient in doing his or her job.
Technical Abstract: Molecular tools have not identified markers for host plant resistance to fall armyworm [Spodoptera frugiperda (J. E. Smith)], one of the most damaging insect pests in the southeastern U.S., in turfgrasses. Available QTLs in corn have not been further assessed for utility as comparative markers for the trait across related taxa. This study reports a linkage map of the region conferring major control of fall armyworm resistance in zoysiagrass. One genomic SSR (ZgAg136) and one AFLP (Zgaw216) were linked to and flanking the fall armyworm resistance locus (Zfawr1) by 6.3 and 8.8 cM, respectively. These markers offer immediate value towards marker-assisted selection for fall armyworm resistance in zoysiagrass and potentially across additional important crops. Non-synteny between fall armyworm resistance loci in zoysiagrass and maize was indicated by the absence of linkage between 38 candidate markers from maize fall armyworm resistance QTL regions and Zfawr1. As a major-effect locus and putative novel source for fall armyworm resistance gene(s), Zfawr1 is a promising target for map-based cloning.