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Irradiance Response Of Tall Fescue Genotypes With Contrasting Levels Of Photosynthesis And Yield, Wallace Wilhelm, C. J. Nelson

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The purpose of this study was to determine if genotype by irradiance interactions or genetic variation in diurnal trends of CO, exchange rate (CER) influenced the CER-yield relationship in tall fescue (Festuca mundinucea Schreb.). Genotypes were selected in the field for high CER-high yield, high CER-low yield, low CER-high yield, and low CER-low yield. Responses of CER to photosynthetic photon flux density (PPFD) of these genotypes were determined using both growth chamber- and field-grown material. The shapes of the PPFD response curves were similar for all genotypes, and saturation occurred at approximately 1,200 μE m^-2 sec^-1 (400 …