Date of Award:

5-2020

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Committee

Paul Johnson

Committee

Shaun Bushman

Committee

Kelly Kopp

Abstract

Diminishing water sources in the Intermountain West have led to increased use of alternative sources of water. These sources, such as reclaimed water, generally have elevated salinity levels that may slow growth, and cause a decline in turfgrass quality. Kentucky bluegrass (Poa pratensis L.) is sensitive to salt stress, but is otherwise very well adapted to many turfgrass areas because of its dark color, durability, ability to recover from wear, and soft texture. Because of these positive traits, it has been the subject of selection for salt tolerance. This study was designed to evaluate the salt tolerance of hybrids from parents that had previously recorded higher salt tolerance, and parents with higher quality traits. My hypothesis was that hybrids from these parent would have mid-parent salt tolerances.

Thirty-one Kentucky bluegrass entries were included in this experiment, ten parents and twenty-one hybrids. Parents and hybrid plants were irrigated with increasing salinity levels. Plants were irrigated every-other-day with an automated boom irrigation system. Treatments began at a lower salinity level (3 dS m-1) for two weeks then increased to a higher salinity level (6 dS m-1) for the remainder of the eight-week experiment. Electrolyte leakage was measured to quantify salt stress along with visual quality ratings of plant health. The experiment was replicated 4 times over the course of 3 years.

There was significant variation in salt tolerance among the different parents and hybrids. Grasses demonstrating higher salt tolerance generally did so during all four replications of the experiment. Of the hybrids that were evaluated, six demonstrated improved salt tolerance. The majority of these hybrids were offspring of parents: 768, ‘North Star’, 827, and 603. The numbered parents are breeding lines in the USDA-USU bluegrass program. I concluded that some Kentucky bluegrass hybrids have potential for use in environments with elevated salinity levels.

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