Submitted to: International Neotyphodium Grass Interactions
Publication Type: Proceedings
Publication Acceptance Date: February 3, 2004
Publication Date: May 19, 2004
Citation: Belesky, D.P., Burner, D.M. 2004. Germination and seedling development of a tall fescue cultivar in response to native and novel endophyte. Proc. 5th International Symposium on Neotyphodium/Grass Interactions. R. Kallenbach, et al., (eds). III-305: Fayetteville, AR. Interpretive Summary: Some fungi live entirely within a host plant and can have detrimental effects on the physiology and behavior of grazing livestock that consume the plant ' fungus association. The association is very specific, but new technologies have allowed introduction of certain fungal strains into productive plant hosts that do not have detrimental effects on grazing livestock. Fungal infection often benefits productivity and persistence of the host plant, but the influence of novel associations on host plant germination and seedling growth is unclear. Results are mixed suggesting that environmental conditions can influence the expression of endophyte effects on germination. A controlled environment experiment was conducted to determine how tall fescue seeds germinated and seedlings developed, when plants hosted a native or novel endophyte, or when they were non-infected. The plants hosting the novel endophyte had the slowest germination and produced fewer tillers than non-infected plants or plants with the native endophyte. Differences in germination and tillering could influence establishment of the stand, and decrease competitive ability with other plants in a pasture over the long term as the host ' association ages and competition among plants in the community occurs.
Technical Abstract: Novel non-toxic endophytes inserted into host plant cultivars can elicit specific metabolic responses that minimize the harmful effects of endophyte-infected grasses on grazing livestock. However, very little is known about the influence of novel endophytes on germination and seedling establishment. Seedling establishment is a critical component determining the competitive fitness of members of a plant community. A controlled environment experiment was conducted to determine germination rate, dry matter allocation patterns in seedling plants, leaf and tiller appearance rates, and tiller production of repeatedly defoliated tall fescue (Festuca arundinacea Schreb.) plants (cv. Jesup), differing in endophyte [native (J+); non-infected (J-); non-toxic endophyte, (Max-Q)]. Association influenced establishment (germination) and consolidation (tillering), but not growth mechanisms such as leaf appearance and elongation of 42-d old seedlings. There were significantly fewer tillers produced by Max Q than either J+ or J-seedling plants. There were positive relationships between whole plant mass, and tiller production with stembase nonstructural carbohydrates. Lower total germination, delayed germination and a lower rate of tiller production relative to other host-endophyte associations could place Max Q plants at a competitive disadvantage and influence plant persistence and sward composition.