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COLD TOLERANCE OF SWITCHGRASS AND BIG BLUESTEM SEEDLINGS (SELECTION, PHOTOSYNTHESIS, SEEDLING-VIGOR)
Abstract
The seeding of big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) in pasture and range has been limited by slow seedling growth in the spring. Improved germination and growth at low temperatures would increase the likelihood of success for early spring plantings. The objectives of this study were to determine if the photosynthetic rates of big bluestem and switchgrass seedlings are reduced by cold (4.5 C) night treatments, to investigate the effects of divergent selection for high and low seedling fresh weight in a cold-night growth chamber regime, and to examine alternative selection techniques which might be used to improve seedling cold tolerance. Switchgrass carbon exchange rate (CER) was reduced approximately 20% by one night at 4.5 C in a growth chamber. Big bluestem CER was not affected by the same treatment. This cold-night treatment did not affect the rate of oxygen evolution of switchgrass leaf pieces. Southern switchgrass cultivars tended to have higher average leaf elongation rates (ALER) in both warm- and cold-night chambers. Progeny from high (HS) and low (LS) fresh weight switchgrass selections had significantly higher ALERs than 'Pathfinder' (PA) in the cold-night chamber. There were no significant differences in ALER among PA, LS, and HS in the warm-night chamber. At low temperatures, LS and HS tended to germinate more rapidly than PA. For both big bluestem and switchgrass, the progeny of high fresh weight selections had higher seedling fresh weights than the progeny of low fresh weight selections in the cold-night chamber. The same was true for big bluestem, but not switchgrass, in the warm-night chamber. No significant seedling fresh weight differences were observed in the field. No significant differences in CER were found among LS, HS, and PA. For big bluestem, progeny from high fresh weight selection (HB) had a higher respiration rate at 10 C than progeny from low fresh weight selections (LB) and 'Pawnee' (PW). Selection based on seedling fresh weight in a cold-night growth chamber regime appears to be an effective and practical technique for improving seedling cold tolerance and increasing seedling vigor.
Subject Area
Botany
Recommended Citation
JOLITZ, EVAN C, "COLD TOLERANCE OF SWITCHGRASS AND BIG BLUESTEM SEEDLINGS (SELECTION, PHOTOSYNTHESIS, SEEDLING-VIGOR)" (1984). ETD collection for University of Nebraska-Lincoln. AAI8423796.
https://digitalcommons.unl.edu/dissertations/AAI8423796