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

Abstract

A network of 21 experiments was established across nine countries on four continents and spanning both hemispheres, to evaluate the relative performance of early generation perennial cereal material derived from wheat, rye, and barley and to inform future breeding strategies. The experimental lines were grown in replicated single rows, and first year production and phenology characteristics as well as yield and persistence for up to three years were monitored. The study showed that the existing experimental material is all relatively short-lived (≤3 years), with environments that are milder in summer and winter generally conferring greater longevity. No pedigree was superior across this diverse network of sites although better performing lines at the higher latitude sites were generally derived from Thinopyrum intermedium. By contrast, at lower latitudes the superior lines were generally derived from Th. ponticum and Th. elongatum parentage. The study observed a poor relationship between year 1 performance and productivity in later years, highlighting the need for perennial cereal material with greater longevity to underpin future experimental evaluation, and the importance for breeding programs to emphasize post-year 1 performance in their selections. Hybrid lines derived from the tetraploid durum wheat generally showed greater longevity than derivatives of hexaploid wheat, highlighting potential for greater use of Triticum turgidum in perennial wheat breeding. We advocate a model in future breeding initiatives that develops perennial cereal genotypes for specific target environments rather than a generic product for one global market. These products may include a diversity of cultivars derived from locally adapted annual and perennial parents. In this scenario the breeding program may have access to only a limited range of adapted perennial grass parents. In other situations, such as at very high latitude environments, perennial crops derived from barley or rye may have a better chance of success than those derived from wheat. In either case, development and selection of the perennial parent for adaptation to local environments would seem fundamental to success.

Genome mapping of quantitative trait loci (QTL) controlling domestication traits of intermediate wheatgrass (Thinopyrum intermedium)

“…However, unlike wheat, IWG is usually self-incompatible meaning that most populations are highly heterogeneous and most individuals are highly heterozygous (Jensen et al 2016;Jensen et al 1990; Kantarski et al 2017;Zhang et al 2016). Wheat-Thinopyrum hybrids have also been utilized for the development of perennial grain crops (Curwen-McAdams and Jones 2017; Hayes et al 2018), but commercial production of these plant materials has not yet been realized because it has been difficult to introgress and stabilize this complex trait in wheat. However, parallel efforts to directly domesticate IWG itself as a perennial grain crop (Cox et al 2006;Cox et al 2010;Wagoner 1990) have led to small-scale production and utilization of IWG grain or flour for baking, beverages, and other edible food products (DeHaan and Ismail 2017).…”

Strategies, Advances, and Challenges in Breeding Perennial Grain Crops

“…Wide hybridization is attractive because, if successful, the new hybrid species can largely inherit highly developed traits such as yield and end-use quality from the already domesticated annual parent. Challenges arise, however, when the chromosome sets (genomes) or number of chromosome sets (ploidy level) in the annual and perennial parents do not match and/or do not recombine during meiosis (see, for example, papers by Cox et al [27] and Hayes et al [28] in this volume).…”

“…× Thinopyrum spp.) [28], rice (Oryza sativa × O. longistaminata) [35], and buckwheat (Fagopyrum spp. × Fagopyrum spp.)…”

Integrating multipurpose perennial grains crops in Western European farming systems

“…Adebiyi et al (2016) termed these innovations "radical transformative technologies" as "their architecture, functionality, component principles and underlying science markedly depart from existing agricultural systems" and suggests perennial grains as one of these "radical transformations". While other regions such as North America and Australia have been conducting research on perennial grain crops for more than a decade, similar research is still rare in Western Europe (Hayes et al, 2018). Recently a research program in France was set up in 2017.…”

“…Perennial grain: potential to provide ecosystem services for Western Europe Although current breeding efforts are promising and suggest further yield improvements will be forthcoming, IWG is currently unable to compete with annual counterparts in terms of grain productivity, mainly due to low harvest index which is around 0.10 (Culman et al, 2013;DeHaan et al, 2018). In contrast, perennial grain accessions obtained from the hybridization of domesticated varieties with close perennial relatives, most often using crosses between wheat (Triticum L.) and perennial Triticeae from the Thinopyrum genus, could be markedly higher yielding but also experience much lower perenniality and regrowth vigor (Cox et al, 2006;Hayes et al, 2018). Currently, plant breeders are working to improve breeding strategies and agronomic traits of perennial grains, including yield, threshability, favorable phenology, shattering rate, and plant persistence (Cox et al, 2010;DeHaan et al, 2018DeHaan et al, , 2014DeHaan et al, , 2005Hayes et al, 2012;Kantar et al, 2016).…”