Winter hardiness of Miscanthus (II): Genetic mapping for overwintering ability and adaptation traits in three interconnected Miscanthus populations

Abstract

Miscanthus × giganteus (M×g) is the primary species of Miscanthus for bioenergy feedstock production. The current leading biomass cultivar, M×g ‘1993‐1780’, is insufficiently adapted in temperate regions with cold winters such as USDA hardiness zone 5 (average annual minimum temperature of −28.9 to −23.3°C) or lower. Three interconnected Miscanthus F1 populations that shared a common parent were planted in a replicated field trial at Urbana, IL (hardiness zone 5b; average annual minimum temperature of −26.1 to −23.3°C) in spring 2011. The winter of 2013–2014 was especially cold in Urbana, with a minimum soil temperature at 10 cm of −6.2°C and a minimum air temperature of −25.3°C, giving us an opportunity to evaluate hardiness on established year‐3 plants. The parent in common to all three populations, M. sinensis ssp. condensatus ‘Cosmopolitan’, is native to maritime southern Japan, and in Urbana, it is winter‐damaged most years. In contrast, the three other parents, M. sacchariflorus ‘Robustus’ (MapA), M. sinensis ‘Silberturm’ (MapB), and M. sinensis ‘November Sunset’ (MapC), are typically winter hardy in Urbana. Nearly all MapA progeny plants survived and grew vigorously in spring 2014, whereas in MapB and MapC, many progeny plants did not survive the winter, and most of the survivors were severely damaged, with poor vigor. Negative correlations between overwintering ability and spring regrowth date and autumn dormancy date suggested that the genotypes most likely to survive winters were those that emerged early in spring and/or went dormant early in autumn. Using joint‐population analysis, we identified 53 quantitative trait loci (QTLs) for nine adaptation traits, including nine QTLs for overwintering ability and 11 for spring hardiness scores. Many biologically intuitive candidate genes were observed within or near the QTLs detected in this study, suggesting their validity and potential for further study.

Winter hardiness of Miscanthus (I): Overwintering ability and yield of new Miscanthus ×giganteus genotypes in Illinois and Arkansas

“…In contrast to the first-year plants in this study, in a parallel study (Dong et al, 2018b) over the cold 2013-2014 winter at Urbana, we observed that third-year plants of M×g '1993-1780' had a high survival rate, but hardiness scores indicated that the plants had been damaged, with relatively few and weak late-emerging shoots. However, the third-year plants of M×g '1993-1780' subsequently recovered by June (Dong et al, 2018b), confirming that mature field plantings of Miscanthus are more resilient to low-temperature stresses during the winter than first-year plants.…”

“…In our previous studies of M×g ‘1993‐1780’ at Urbana, when temperatures were warmer than those observed during the current study, we observed no stand losses during the first winters, and third year yields were 7–8 Mg/ha greater than during the current study (Dong et al, ; Kaiser et al, ). In contrast to the first‐year plants in this study, in a parallel study (Dong et al, ) over the cold 2013–2014 winter at Urbana, we observed that third‐year plants of M×g ‘1993‐1780’ had a high survival rate, but hardiness scores indicated that the plants had been damaged, with relatively few and weak late‐emerging shoots. However, the third‐year plants of M×g ‘1993‐1780’ subsequently recovered by June (Dong et al, ), confirming that mature field plantings of Miscanthus are more resilient to low‐temperature stresses during the winter than first‐year plants.…”

Winter hardiness of Miscanthus (III): Genome‐wide association and genomic prediction for overwintering ability in Miscanthus sinensis

“…Correspondence between QTLs for overwintering ability detected across three interconnected diploid F 1 Miscanthus populations (Dong, Liu, et al, ) and genome‐wide associations (GWA) for overwintering ability in an M. sinensis diversity panel. Black dashed bars represent Miscanthus linkage groups (LGs), and blue bars represent S. bicolor (version 3.0) LGs.…”

“…Overwintering ability is an important selection criterion for perennial bioenergy crops in temperate environments (Burner, Tew, Harvey, & Belesky, ; Clifton‐Brown & Lewandowski, ; Clifton‐Brown et al, ). Insufficient overwintering ability is a consistent limitation of M×g ‘1993–1780' in regions with cold winters, such as those in USDA hardiness zone 4 (average annual minimum air temperature of −34.4°C to −28.9°C; U.S. Department of Agriculture, ) and lower, and an intermittent problem in hardiness zone 5 (average annual minimum air temperature of −28.9°C to −23.3°C) and zone 6 (average annual minimum air temperature of −23.3°C to −17.8°C) (Clifton‐Brown & Lewandowski, ; Dong, Green, et al, ; Dong et al, ; Dong, Liu, et al, ; Heaton et al, ; Jørgensen, Mortensen, Kjeldsen, & Schwarz, ; Lewandowski, Clifton‐Brown, Scurlock, & Huisman, ). Clifton‐Brown and Lewandowski () observed variation among two M×g, one M. sacchariflorus , and two M. sinensis grown at four field trial locations in Europe for ability to survive the first winter, and this was not associated with plant size or early senescence in the first autumn.…”

“…Given that Miscanthus is a long‐lived perennial, marker‐assisted selection is expected to enable plant breeders to efficiently select superior genotypes and greatly improve breeding efficiency. However, few GWA or genomic prediction studies on Miscanthus have been published and these have focused primarily on yield traits of M. sinensis (Nie et al, ; Slavov et al, ,) and M. sacchariflorus (Clark et al, ); to the best of our knowledge, none GWA studies have been published on overwintering ability, and only one genetic mapping study reported QTLs for overwintering ability (Dong, Liu, et al, ). To facilitate the use of a previously characterized M. sinensis germplasm panel (Clark et al, ,) and identify superior genotypes for breeding, we evaluated the overwintering ability of M. sinensis genotypes in this germplasm panel in North America and Asia.…”