Abstract
Annual plants are currently the dominant growth habit for grain production systems but often create agroecosystems with negative environmental consequences. Developing grains with a perennial growth habit provides an opportunity to produce staple crops in a more environmentally beneficial manner. Amphiploids of perennial tall wheatgrass (Thinopyrum elongatum) and common annual wheat (Triticum aestivum) have been produced for wheat-like traits while exhibiting post-sexual cycle regrowth (PSCR). Here we report results from two experiments at two locations in the Palouse region of the U.S. Pacific Northwest (PNW) designed to (1) evaluate a subset of the current perennial grain germplasm base and (2) test post-harvest management strategies on key perennial growth habit traits. The first experiment evaluated 18 putative perennial amphiploid lines, two annual wheat varieties, and one intermediate wheatgrass variety (Thinopyrum intermedium) for yield, PSCR, key agronomic traits, and grain quality characteristics. Results from this trial showed mean yields ranged from 713 to 2874 kg/ha among the amphiploids and 1627 to 6867 kg/ha with the annual wheat varieties. Variation across the amphiploids was found for key agronomic and quality traits, indicating potential for continued selection and improvement. When compared to the two annuals, the four highest-yielding amphiploids produced the same yield at one location but 50 to 60% less at the other. Regarding grain qualities, amphiploids had lower test weights and thousand kernel weights, smaller kernel diameters, lower starch content, and higher protein, ash, and fiber. The second experiment investigated the effect of post-harvest residue management on PSCR and winter survival of two amphiploids using mowing, burning, and a control. Mowing the residue and PSCR significantly increased winter survival across both amphiploids at one location from 3% in the control to 63% in the mowed treatment. Burning the residue did not improve survival. Our results address three important challenges in perennial grain development in the Palouse region: selecting a stable perennial habit, increasing grain yield, and improving marketable grain quality traits. Each of these challenges will require significant research efforts by plant breeders and agronomists prior to widespread adoption of perennial grains in the Palouse region of the PNW.
Highlights
The Palouse region of the Pacific Northwest is sui generis; a highyielding, rainfed grain-producing area with a history of some of the highest dryland grain yields and most severe soil erosion rates in the United States (Steiner, 1987; Duffin, 2007)
Higher emergence and winter survival was observed at the Tukey location as compared to Higbee, though most genotypic means were not different from each other with the annual and amphiploid lines ranging from 84 to 95% emergence
The rhizomatous trait in O. longistaminata has been shown to be controlled by a complex gene network, which suggests that the phytohormone auxin acts as a negative regulator of rhizome development whereas gibberellin acts as an activator
Summary
The Palouse region of the Pacific Northwest is sui generis; a highyielding, rainfed grain-producing area with a history of some of the highest dryland grain yields and most severe soil erosion rates in the United States (Steiner, 1987; Duffin, 2007). The Palouse region is temperate with warm, dry summers (Köppen Classification Csb), and an average annual precipitation ranging from 280 to 660 mm (Hall et al, 1999). Considerable evidence suggests conventional cereal-legume systems in the Palouse have degraded soil health and increased soil pollution (Saxton et al, 2000). Annuals typically have shallower rooting depths and lower root densities (Glover et al, 2010b). Even with crop management advances, such as no-tillage practices, these traits limit their access to nutrients and water, leave croplands more vulnerable to soil degradation and erosion, and make annual plants less resilient to the increased environmental stress expected from climate change (Glover and Reganold, 2010)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
