Hierarchical Analysis of Switchgrass Morphology
- Arvid Boe *a and
- Michael D. Caslerb
Switchgrass (Panicum virgatum L.) has potential as a biomass crop in North America. Our objective was to determine effects of cultivar and location on morphological traits that influence biomass in switchgrass. Six cultivars with origins from 37° N, 88° W (Cave-In-Rock and Shawnee) to 46° N, 100° W (Dacotah) were evaluated in 1-yr-old swards at Bristol and South Shore, SD; in 3-yr-old swards at Brookings, SD, and Arlington, WI; and in 15-yr-old swards at Pierre, SD, for biomass; tillers m−2; reproductive tiller proportions by count and weight; weight tiller−1; phytomers tiller−1; leaf, stem, and inflorescence components of tiller weight; and sheath and stem components of phytomer weight. Biomass production was related to region of cultivar origin [e.g., Shawnee produced two times more than Dacotah (6.2 Mg ha−1)]. Tiller density was highest for Dacotah (1090 tillers m−2) and lowest for Cave-In-Rock (520 tillers m−2). Reproductive tiller fractions by count were plastic and higher at Arlington (0.81) than Brookings (0.08). Weights per reproductive tiller ranged from 0.7 g (Dacotah) to 3.4 g (Cave-In-Rock). Phytomers per tiller was not plastic (5.2 for Dacotah to 7.4 for Cave-In-Rock). Internode weight exhibited a basipetal increase and was highly plastic. Cultivars responded similarly to location effects on tillers m−2, weight tiller−1, and biomass production. Cultivar differences for biomass production were attributed to variation at tiller (phytomers tiller−1) and phytomer (weight phytomer−1) levels.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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