Agronomic Assessment of Perennial Wheat and Perennial Rye as Cereal Crops

Abstract

Perennial wheat (Triticum aestivum L. × Thinopyrum spp.) and perennial rye (Secale cereale L. × S. montanum) are novel hybrid species under development as alternatives to annual cereal crops. We conducted a 2‐yr field study with a split plot design to evaluate agronomic performance, including yield, phenology, and biomass production, of perennial accessions of wheat and rye, along with annual analogs. This is one of the first studies to rigorously compare agronomic performance of 2‐yr‐old plants to 1‐yr‐old plants in perennial cereals. Perennial wheat produced 1.0 to 1.6 Mg ha−1 grain yield, 50% of annual wheat (2.7 Mg ha−1), while perennial rye produced 1.3 Mg ha−1, 73% of annual rye (1.8 Mg ha−1). Modest yields from perennials relative to annuals reflected lower harvest index, lower yield per tiller, and less kernel mass. One‐year‐old and 2‐yr‐old perennial plants had similar seed yields, yield components, and biomass production, indicating that plant age had little effect on these parameters and older plants maintained yield potential. In contrast, phenology did vary with plant age, and showed a shift toward earlier spring growth and later flowering dates in older perennial plants. This illustrates an expanded vegetative period for regrowing plants of these perennial cereals. There appears to be potential for producing an early season forage crop from these cereals, although biomass yields were not high at this site and regrowth was not always reliable. Overall, performance of perennial rye was consistent with a viable new cereal crop. On the other hand, perennial wheat requires further selection for allocation of biomass to grain and vigorous regrowth.

The Performance of Early-Generation Perennial Winter Cereals at 21 Sites across Four Continents

“…For perennial wheat this may indicate either a lack of adaptation or a lack of a typical perennial growth habit, which may be critical at this location. Cultivation of perennial cereal rye has occurred since ancient times in parts of Eastern Europe [1], and the impressive performance of the rye lines compared to the range of perennial wheats, in terms of persistence and grain yield (see Figure 6f), at the one site in the present study is consistent with the favourable performance of perennial rye compared to perennial wheat at Michigan, USA [10]. Currently, perennial cereal rye has better prospects as a near-term commercial crop than perennial wheat from a North American and European perspective.…”

“…Although Larkin et al [9] identified two perennial wheat lines that survived and yielded grain over four successive years at Cowra, Australia, plots in that study had declined to only single individual survivors. Poor longevity often limits the timeframe of evaluation to no more than two years [10,11], hampering the ability to explore the broader ecosystem benefits of perennial cereal crops.…”

“…Four hybrid wheat × Th. elongatum ([Host] D. R. Dewey) lines developed at Washington State University were tested in three studies run independently of each other; one in Michigan, USA [10], one in Washington, USA [16], and one in New South Wales, Australia [17]. Attempted comparisons between these discrete studies are problematic for a number of reasons, not least of all, the different objectives and methodologies undertaken.…”

Understanding perennial wheat adoption as a transformative technology: evidence from the literature and farmers

“…In the USA, breeding programs focusing on hybridization between annual wheat and its perennial relatives are the most advanced in development of a perennial grain crop (Jaikumar et al, 2012). Perennial wheat is not yet commercially available, but for its potential benefits to be realized, farmers would have to be interested in adopting it.…”

“…Agroforestry has also been so identified because it is based on a farming practice which deliberately incorporates perennial woody plants into cropped fields. Like agroforestry systems, perennial grain systems may demonstrate what Jaikumar et al (2012) describe as 'delayed reproductive investment' (p. 1716). All of these transformative technologies are widely associated with gains in ecosystem services.…”