Cultivar diversity as a means of ecologically intensifying dry matter production in a perennial forage stand

Abstract

Abstract. The relationship between genotypic diversity and productivity has not been adequately explored in perennial forage production systems despite strong theoretical and empirical evidence supporting diversity's role in ecosystem functioning in other managed and unmanaged systems. We conducted a two-year field experiment with six cultivars of an agriculturally important forage grass, Lolium perenne L. (perennial ryegrass). Dry matter production of L. perenne and the weed community that emerged from the soil seed bank were measured each year in treatments that ranged from cultivar monocultures to three-and six-way cultivar mixtures, all sown at a constant seeding rate. Mean L. perenne dry matter production increased with increasing cultivar diversity and was highest in mixtures that contained cultivars representing the greatest additive trait range (calculated on rankings of three traits: winter hardiness, heading date, and tolerance to grazing). Mixtures had greater yields than those predicted by the mean of their component monoculture yields, but there was evidence that highly productive cultivars may have dampened over-yielding in mixtures. Weed abundance was correlated with L. perenne dry matter, but not L. perenne cultivar diversity. These results suggest that multi-cultivar mixtures may have utility as an approach to ecologically intensifying perennial forage production. Additional research will be necessary to determine the mechanisms responsible for the over-yielding observed in this study and the generality of these findings.

Plant community response to switchgrass (Panicum virgatum) population source in establishing prairies

“…However, increased homogeneity at the landscape scale confers a greater risk of pathogen and pest infestations (Gustafson et al 2003, Robertson et al 2008, Hartman et al 2011). This suggests that the inclusion of undomesticated strains in switchgrass biomass plantings may increase site-level yield, as was found for mixtures of switchgrass cultivars (Morris et al 2016) and perennial ryegrass (Lolium perenne; Pollnac et al 2014). Additionally, we found that, at each site, particular undomesticated populations produced more biomass than particular cultivars even though cultivars as a group were more productive.…”

“…Additionally, we found that, at each site, particular undomesticated populations produced more biomass than particular cultivars even though cultivars as a group were more productive. This suggests that the inclusion of undomesticated strains in switchgrass biomass plantings may increase site-level yield, as was found for mixtures of switchgrass cultivars (Morris et al 2016) and perennial ryegrass (Lolium perenne; Pollnac et al 2014).…”

Major shifts in species’ relative abundance in grassland mixtures alongside positive effects of species diversity in yield: a continental‐scale experiment

“…Legume persistence in mixed swards could be enhanced by selecting legume species and cultivars with proven persistence abilities for the local environment and that have good competitive abilities, and by matching legumes with grasses that are less aggressive in competition (Annicchiarico & Proietti ). Genotypic diversity has successfully increased yields of L. perenne (Pollnac, Smith & Warren ) suggesting that enhancing functional trait diversity by combining mixtures of cultivars with mixtures of species may lead to additional diversity effects to ecosystem function than mixing species alone. Further research is needed to explore this.…”

How Can Sustainable Agriculture Increase Climate Resilience? A Systematic Review

“…However, there is disagreement in the literature about the impacts of genetic management on yield increases. While some authors argue that crop and cultivar diversity is positively and significantly related to production [120][121][122], others maintain that a productivity increase is observable only in normal years, not during extreme weather events or epidemics [123]. Notably, most of the research documenting the benefits of diversification evaluated a single ecosystem service [124].…”