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United States Department of Agriculture

Agricultural Research Service

Title: Morphological Characteristics of Big Bluestem and Switchgrass Plants Divergently Selected for Seedling Tiller Number

Authors
item Smart, Alexander - SO DAKOTA STATE UNI
item Moser, Lowell - UNI OF NE
item Vogel, Kenneth

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 25, 2003
Publication Date: March 1, 2004
Citation: Smart, A.J., Moser, L.E., Vogel, K.P. 2004. Morphological characteristics of big bluestem and switchgrass plants divergently selected for seedling tiller number. Crop Science. 44:607-613.

Interpretive Summary: Switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) seedling tiller number at 6 to 8 wk after planting was genetically modified by breeding in selected populations. Mature big bluestem and switchgrass plants from populations developed by divergent selection for seedling tiller number differed for mature plant morphological and physiological characteristics and forage yield. Selection at the seedling stage for tiller number appears to be an effective method to develop switchgrass and big bluestem genotypes differing in yield tiller-1, which has been shown to affect herbage yield when grown in swards. Selection for tiller number may be an effective method of accelerating breeding progress for increasing biomass yield of switchgrass for use in bio-energy production systems.

Technical Abstract: Big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) seedling tiller number at 6 to 8 wk after planting was genetically modified by breeding in selected populations. Objectives of this study were to determine if mature big bluestem and switchgrass plants from populations developed by divergent selection for seedling tiller number differed for mature plant morphological and physiological characteristics and forage yield. Experiments were conducted in field and greenhouse studies at Lincoln, NE from 1999 through 2001. Seedlings from big bluestem and switchgrass populations that differed significantly for seedling tiller numbers were transplanted into the field and pots for study. Leaf width, leaf length, plant height, and number of tillers plant-1 were measured. Plant yield was determined in the year after establishment. Leaf elongation rate was measured in greenhouse studies. Mature plant morphological characteristics differed between multiple tiller plants and single tiller plant types for both big bluestem and switchgrass. Yield tiller-1 was greater for single tiller plants than multiple tiller plants. Leaf elongation rate was positively correlated with plant height, yield plant-1, and yield tiller-1. Selection at the seedling level for tiller number appears to be an effective method to develop genotypes differing in yield tiller-1, which has been shown to affect herbage yield when grown in swards.

Last Modified: 12/22/2014