Assessment of Drought Tolerance of Miscanthus Genotypes through Dry-Down Treatment and Fixed-Soil-Moisture-Content Techniques

Abstract

Miscanthus, a high-yielding, warm-season C4 grass, shows promise as a potential bioenergy crop in temperate regions. However, drought may restrain productivity of most genotypes. In this study, total 29 Miscanthus genotypes of East-Asian origin were screened for drought tolerance with two methods, a dry-down treatment in two locations and a system where soil moisture content (SMC) was maintained at fixed levels using an automatic irrigation system in one location. One genotype, Miscanthus sinensis PMS-285, showed relatively high drought-tolerance capacity under moderate drought stress. Miscanthus sinensis PMS-285, aligned with the M. sinensis ‘Yangtze-Qinling’ genetic cluster, had relatively high principal component analysis ranking values in both two locations experiments, Hokkaido University and Brigham Young University. Genotypes derived from the ‘Yangtze-Qinling’ genetic cluster showed relatively greater photosynthetic performance than other genetic clusters, suggesting germplasm from this group could be a potential source of drought-tolerant plant material. Diploid genotypes showed stronger drought tolerance than tetraploid genotypes, suggesting ploidy could be an influential factor for this trait. Of the two methods, the dry-down treatment appears more suitable for selecting drought-tolerant genotypes given that it reflects water-stress conditions in the field. However, the fixed-SMC experiment may be good for understanding the physiological responses of plants to relatively constant water-stress levels.

Investigating applied drought in Miscanthus sinensis; sensitivity, response mechanisms, and subsequent recovery

“…Second generation biofuel crops are promising candidates for sustainable cultivation on marginal lands (Pancaldi & Trindade, 2020), especially C4 perennials such as miscanthus and switchgrass. Nonetheless, several studies on both crops reported a substantial decrease in yield under drought (Barney et al, 2009; Berdahl et al, 2005; Weng et al, 2022). Enhancing tolerance, however, ensures yield stability; a prerequisite for economically viable exploitation of drought‐affected lands for bioenergy production (Ings et al, 2013).…”

“…This presents a major obstacle for its adoption on a wider commercial scale given its costly plot setup via rhizome propagation (Xue et al, 2015), in addition to hindering its optimization via breeding (Jakob et al, 2009). Alternatively, the seedbased M. sinensis is gaining interest as a suitable replacement, owing to its genetic diversity (Clifton-Brown et al, 2017;Sacks et al, 2013), better tolerance to abiotic stresses (Clifton-Brown & Lewandowski, 2000a;Weng et al, 2022), and generally lower cell wall lignin contents (Qin et al, 2012;van der Weijde et al, 2017a). The latter is strongly associated with a higher saccharification efficiency (Van der Weijde et al, 2017c;Zhao et al, 2012).…”

“…Equally important is identifying biomarkers of stress, ensuring an early detection of vulnerability; crucial for pre‐screening in breeding programs and reducing mortality rates in plot setups on marginal lands. This pressing need, manifested in the scientific community's growing interest in examining the impact of drought on second generation biofuel crops (Chen et al, 2020; Lovell et al, 2016; Taylor et al, 2016; Weng et al, 2022). Some studies, however, especially those on miscanthus, focused on the stress‐imparted changes to cell wall quality and saccharification efficiency (Da Costa et al, 2019; Van Der Weijde et al, 2017b).…”

“…Alternatively, the seed‐based M . sinensis is gaining interest as a suitable replacement, owing to its genetic diversity (Clifton‐Brown et al, 2017; Sacks et al, 2013), better tolerance to abiotic stresses (Clifton‐Brown & Lewandowski, 2000a; Weng et al, 2022), and generally lower cell wall lignin contents (Qin et al, 2012; van der Weijde et al, 2017a). The latter is strongly associated with a higher saccharification efficiency (Van der Weijde et al, 2017c; Zhao et al, 2012).…”

“…(Yang et al, 2021). Accordingly, exploiting M. sinensis ample genetic diversity via comparative studies, is pivotal in screening for better performing genotypes and the consequent breeding efforts toward improved tolerance in this crop (Weng et al, 2022). This was evident in the dissimilar impact of water-deficiency (Van Der Weijde et al, 2017b) and salt (Chen et al, 2017) on diverse populations of M. sinensis genotypes, and likewise the differential expression of common regulatory pathways after flooding and drought treatments (De Vega et al, 2021).…”