Evaluating native pre-variety germplasms for use in dryland restoration

Abstract

Sourcing appropriate plant material for direct seeding is fundamental to the sustainable restoration of degraded ecosystems. The Pre-Varietal Germplasm program offers a series of seed certification strategies to facilitate the rapid production, procurement, and distribution of native seeds for restoration. We implemented a multi-year study across 6 sites in the Great Basin, USA, to evaluate recruitment success of 3 bluebunch wheatgrass germplasms: Anatone (selected class, natural track), Columbia (selected class, manipulated track), and Wahluke (source identified class, natural track). Each site and planting year were fully replicated research trials that evaluated germplasm response to climatic and edaphic factors and how these influenced seedling recruitment during the early life stages. Anatone and Wahluke germplasms generally performed as well or better than Columbia for each demographic life stage. Wahluke outperformed Columbia germination and seedling emergence in 82% of the trials, and juvenile establishment in 30% of the trials. Similarly, Anatone germinated, emerged, and established greater than Columbia in 64, 55, and 20% of the trials. Wahluke had greater germination and emergence in 45% of the trials and higher establishment in 10% of the trials. Anatone emergence and establishment outperformed Wahluke in 9 and 20% of the trials, respectively. The best predictors of seedling recruitment were plant material traits that influenced germination timing and emergence, not site climate or edaphic properties. This research emphasizes the need to evaluate plant material traits and incorporate seeding strategies that increase seedling emergence to achieve juvenile establishment objectives.