Wild Miscanthus Germplasm in a Drought-Affected Area: Physiology and Agronomy Appraisals

Abstract

Predictions of future climate scenarios indicate that yields from perennial biomass crops (PBCs) growing in the Mediterranean region are likely to decline due to prolonged drought. Among PBCs, Miscanthus grasses with C4 photosynthesis combine high yield potentials and water use efficiencies. However, the standard commercial clone M. x giganteus (Mxg), with minimal stomatal regulation, is too sensitive to drought for reliable yields in the Mediterranean regions. This paper screened a diverse panel of thirteen Miscanthus genotypes (M. sinensis, M. floridulus, M. sacchariflorus and Mxg) to identify which types could maximize yield under summer drought conditions typical in the South Mediterranean climate. In the second growing season, significant differences were observed for plant height (from 63 to 185 cm), stem number (from 12 to 208 stems plant−1), biomass yield (from 0.17 to 6.4 kg DM plant−1) and whole crop water use efficiency (from 0.11 to 7.0 g L−1). Temporal variation in net photosynthesis, stomatal conductance, transpiration rate and instantaneous water use efficiency identified different strategies adopted by genotypes, and that genotypes selected from M. floridulus and M. sinensis were better adapted to rainfed conditions and could produce six times more biomass than the Mxg. These accessions are being used as parents in experimental breeding aimed at producing future seed-based drought resilient hybrids.

The Impact of Soil Water Content on Yield, Composition, Energy, and Water Indicators of the Bioenergy Grass Saccharum spontaneum ssp. aegyptiacum under Three-Growing Seasons

“…It is imperative that agriculture will take these threats as opportunities, by diversifying crop options, introducing new cropping systems with locally adapted genotypes combined with sustainable agronomic practices to provide raw material for the bioeconomy and to conserve natural resources [38]. Advanced research on locally adapted plants, aimed at identifying stress-resilient traits and to breed resource-efficient and climate-resilient genotypes, will likely play a key role in strength synergies among farmers, practitioners, and industries to optimize bioeconomy value chains [39][40][41][42][43][44].…”

Identifying Factors Explaining Yield Variability of Miscanthus x giganteus and Miscanthus sinensis Across Contrasting Environments: Use of an Agronomic Diagnosis Approach

“…This was the finding at the Chanteloup site (shallow sandy soil with a maximum soil water capacity of 149 mm and rainfall lower than 400 mm) where M. sinensis obtained higher yields than M. x giganteus. Scordia et al [37] found similar results and showed a low yielding of M. x giganteus compared to M. sinensis established in sandy soil in Italy. In a context of climate change, characterized in several regions by a higher rainfall variability, the choice of genotypes for a perennial crop should be for the most stable yields across years [37] and even better if they are high and stable.…”

“…Scordia et al [37] found similar results and showed a low yielding of M. x giganteus compared to M. sinensis established in sandy soil in Italy. In a context of climate change, characterized in several regions by a higher rainfall variability, the choice of genotypes for a perennial crop should be for the most stable yields across years [37] and even better if they are high and stable. For this purpose, on sites with low water availability and sandy soils, M. sinensis would be a better choice than M. x giganteus.…”

“…Similar results were obtained by da Costa et al [11], who showed that M. sinensis was more tolerant to water stress than M. x giganteus. In water stress conditions, the water use efficiency of M. sinensis was increased by 2% while that of x giganteus was reduced by 7% [37]. The morphology of the plant could explain these results.…”

Linkage mapping evidence for a syntenic QTL associated with flowering time in perennial C4 rhizomatous grasses Miscanthus and switchgrass

“…Miscanthus demonstrates stand and harvest longevity exceeding 15 years (Clifton‐Brown et al., 2019) and, once established, expresses considerable drought (Scordia et al., 2020) and flood (Kam et al., 2020) tolerance with low to zero requirements for herbicide treatments and fertilization (Cosentino et al., 2007). The commercially dominant triploid Miscanthus x giganteus ( Mxg ) is a natural interspecific hybrid between diploid Miscanthus sinensis (2n = 2x = 38) and allotetraploid Miscanthus sacchariflorus (2n = 4x = 76; Greef & Deuter, 1993; Linde‐Laursen, 1993; Rayburn et al., 2009).…”