Susan Fischer
MaxQ tall fescue's effect on biodiversity in a lowland successional field
BSES Senior Research Project 2007

Abstract
Symbiotic relationships occur everywhere in nature and play an important role in the structure and function of ecosystems. Many grass species are known to have a fungal symbiont that provides benefits to the plant, but may also be harmful to animals. One such grass species is tall fescue (Festuca arundinacea), a cool-season perennial grass that covers fifteen million hectares in the United States alone. Tall fescue is so popular because of its ease of establishment, vigor, wide range of adaptation, long grazing season, tolerance to abuse, sufferance of drought and poor soils, and pest resistance. Fescue’s competitive success is due in part to the fact that over two-thirds of tall fescue maintains a symbiotic relationship with an endophytic fungus (Neotyphodium ceonophialum). This endophyte is transmitted through the seeds and colonizes the leaf sheaths, meristems, and internodes of fescue seedlings. There is no external appearance of endophyte infection and spread is only through the seeds of infected plants. The endophyte is beneficial to the grass, but harmful to grazing animals. It contains toxic alkaloids, including ergot alkaloids, lolines, and peramines. Cattle and sheep that graze on tall fescue can suffer from a condition known as fescue toxicosis. Fescue toxicosis causes numerous health problems, including gangrene, low conception rates, poor animal gains, reduced milk production, intolerance to heat, elevated respiration rates, and many more. This is economically damaging, resulting in the loss of hundreds of millions of dollars per year.

In order to reduce the toxicity but retain stand survival, the MaxQ endophyte, a non-ergot, alkaloid-producing endophyte, was developed. This modified endophyte is recognized to be non-toxic to mammals, but little is known about its effect on plant productivity and fitness, competition, and biodiversity. In this experiment, the effect MaxQ tall fescue has on fitness, biodiversity, competition, and productivity was tested in a lowland successional field. The study was performed at Bayles Field, part of the Indiana University Research and Teaching Preserve. In 2002, forty-two (10m 9. × 10m) plots were plowed, disked, and planted with tall fescue seed. Two different fescue seed types, each with three different endophyte infection types, were incorporated into the plots.

The fescue seed types used were Jesup and Georgia-5 (GA). Each seed type was infected with the MaxQ endophyte (MaxQ), infected with the Wild Type endophyte (WT+), and not infected (WT-). The plots were planted by alternating each of the six plot types, yielding seven plots of each endophyte/seed combination.

Significant differences occurred between the wild-type infected (WT+), MaxQ infected (MaxQ), and uninfected (WT-) tall fescue in species richness, total biomass, and tall fescue productivity. MaxQ tall fescue (MaxQ) was found to be more productive and have a higher fitness rate than the uninfected tall fescue (WT-), but worse competitive abilities than the wild-type infected tall fescue (WT+), leading to greater biodiversity. MaxQ tall fescue (MaxQ) has its advantages and disadvantages, comparable to the uninfected (WT-) and wild-type infected (WT+) tall fescue. MaxQ tall fescue is not a faultless solution to the problem, but it is a start and will require further research and testing in order to perfect it. In order to do so, some experiments should be done to test MaxQ tall fescue’s toxicity on smaller mammals, like voles. There should also be further studies done, similar to this one, but with more samples per plot type, providing additional results of greater significance.