Wednesday, 9 November 2005
22

Evaluation of Tall Fescue Genotypes for Heat and Drought Tolerance.

Francis Kirigwi, John Zwonitzer, and Malay Saha. Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401

Tall fescue (Festuca arundinacea Shreb.) is an important cool season forage grass in the Southern Great Plains. Both heat and drought stress affect the productivity and persistence of this crop during the dry hot summer months in this region. The objective of this study was to identify germplasm introductions with potential for growth and persistence under heat and drought stress. Ninety genotypes were collected from different geographical regions and screened under heat and drought stress. In growth chamber experiments, heat treatment was imposed after 3 weeks of transplanting. Temperature was gradually increased from 24°C to a maximum of 42°C and held for 12 days. Temperature was then decreased to 27°C and held for 27 days to allow plant re-growth. Night temperatures were 10 degrees below the maximum day temperature. Genotypes differed for growth vigor, leaf rolling, leaf tip senescence and leaf color. Based on these traits, B1104-32 and B1222-10 were the most heat tolerant while B1222-28 and B1222-30 were the most heat sensitive. When the genotypes were evaluated for electrolyte leakage after treatment with 40% PEG, B1104-2 and B1104-3 was the most heat and drought tolerant while B1104-8 and B1104-20 were the most sensitive. For the drought study, relative water content, osmotic potential and chlorophyll content will be determined. Results from both heat and drought experiments will be presented.

Handout (.PDF format, 755.0 kb)

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