Germination Response of Twelve Accessions of Bouteloua curtipendula (Michx.) Torr. (Poaceae) to a Simulated Winter Temperature Regime

Abstract

Twelve accessions of Bouteloua curtipendula were tested in a laboratory growth chamber to examine the effect of simulated winter temperature on the germination response of the selected accessions of B. curtipendula var. curtipendula (Michx.) Torr. and B. curtipendula var. caespitosa Gould & Kapadia, two botanical varieties of disparate origin. Accessions of the variety curtipendula had significantly higher total germination percentages compared to accessions whose variety was var. caespitosa under the winter treatment. Latitude was also significant with accessions whose origin was farther north exhibiting higher relative germination percentages under the winter treatment. Mean total germination percentage was significantly higher for accessions whose grains were from NPGS seed production facilities under the winter treatment compared to the mean of accessions from wild-collected populations. Mean seed (grain) mass was highly correlated (rs = 0.774) with relative germination percentages, suggesting seed vigor may be an important explanatory factor in germination under stressful conditions.