Date of Award:

7-6-2012

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Advisor/Chair:

Corey V Ransom

Abstract

Forage kochia (Bassia prostrata, [L.] A. J. Scott) (Synonym = Kochia prostrata [L.] Schrad.) is a perennial semi-shrub that is valued for its forage quality and ability to restore degraded rangeland. However, establishment success of forage kochia plantings in western North America has been erratic. These failures leave the land vulnerable to erosion and invasion of undesirable plants. This research focused on the germination dynamics of forage kochia accessions as it relates to harvest date, planting date, age of seed, and environmental conditions. The effect of planting date, age of seed, and environmental conditions on forage kochia germination was elucidated by planting recently harvested (2010) and year-old, cold-stored seed (2009) monthly, during a four-month period at two locations. Two entries were tested, Immigrant, the standard subspecies virescens cultivar, and an experimental line, Sahsel, of subspecies grisea. Regardless of planting date, location, or age of seed, Sahsel exhibited higher germination percentages than Immigrant. The age of the seed lots used also significantly affected (P<0.05) the germination percentage. Field germination averaged over location and planting date of year-old Immigrant seed was 89.5% less than the current-year fresh seed, and similarly year-old Sahsel seed had 83.6% less germination than current-year seed. Although the two locations were subjected to very different weather patterns, the germination percentage of seeds at each location was not significantly different (P=0.3156). In the year we conducted our study (2011), the germination percentage from planting in February was significantly higher (P<0.05) than January, which was significantly higher (P<0.05) than both March and April. In the final set of trials, different harvest dates were tested by collecting seed in October, November, and December from seven forage kochia accessions. Measurements for total seed yield, 100-seed weight, and germination were collected from seed harvested each month. The month of harvest, accession, and month × accession interaction were significant (P<0.05) for each measurement in the study. Two accessions, Pustsel and KZ6Xsel, matured the earliest and had peak seed production at the October harvest (15.1 and 13.4 g plant-1, respectively). The remaining accessions had maximum yield and viable seed from the November harvest.

Comments

This work made publicly available electronically on July 31, 2012.

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