Distinct Species-Level Adaptability of Miscanthus in Saline Soil in the Yellow River Delta, China

Miscanthus is a promising perennial lignocellulosic crop for biomass production. To avoid competing with arable land used for food crops to promote carbon neutrality, cultivating Miscanthus on marginal land, especially in saline soils in China, is a recommended strategy. However, the adaptability of Miscanthus species in saline soil remains largely unknown. In this study, a total of 354 genotypes, including Miscanthus sinensis, Miscanthus floridulus, Miscanthus sacchariflorus, Miscanthus lutarioriparius and interspecific species hybrids derived from M. sinensis and M. lutarioriparius, were evaluated under different planting times (May and August), salinity levels (low and moderate) and pest damage assessment by Helicoverpa armigera in the Yellow River Delta (YRD), in China. The significant effects of planting time on the adaptability of Miscanthus were observed. Planting in May in the YRD, Miscanthus had a lower establishment survival rate (28.76%) and overwintering rate (72.31%), but a dry weight higher than that of planting in August. In contrast, planting in August in the YRD had a very high establishment survival rate (91.14%) and overwintering rate (80.65%), which indicated August was the optimal month for planting Miscanthus in the YRD, while May could be suitable for screening salinity tolerance in Miscanthus. In addition, using the overall adaptability score calculated by establishment survival, overwintering ability, key agronomic traits and pest damage assessments to evaluate all genotypes in this study indicated that the adaptability of M. lutarioriparius was superior to other species. However, M. lutarioriparius is more sensitive to pest damage than others. Furthermore, interspecific hybrids in Miscanthus exhibited outstanding biomass production and adaptability in this region, indicating that creating hybrids would be the best breeding strategy for marginal lands. These results provide an important theoretical basis for the development of Miscanthus in saline soil in the YRD, China.