Thermal requirements for seed germination in Miscanthus compared with Switchgrass (Panicum virgatum), Reed canary grass (Phalaris arundinaceae), Maize (Zea mays) and perennial ryegrass (Lolium perenne)

摘要

The high establishment costs of Miscanthus by clonal propagation are a barrier to widespread deployment. Direct sowing is the cheapest method, but limited field trials have given generally poor results. Miscanthus, a perennial grass with CSUB4/SUB photosynthesis has tropical origins, but is found growing both at high latitudes (40°) and altitudes (1000 m) in Asia. In this paper, we investigate if significant variation in the thermal requirements for germination exist in 10 Miscanthus sinensis half-sib families and compare these with Panicum virgatum (Switchgrass – Trailblazer), Phalaris arundinaceae (Reed canary grass – P10) and Lolium perenne (perennial ryegrass cv AberDart) and maize (Zea mays cv Aviso). The comparisons were made on a thermal gradient bar with a controlled temperature oscillating ± 5 °C on a 12 h cycle and germination was monitored daily for 35 days at mean temperatures ranging from 5.3 to 26.5 °C. Base temperatures were calculated below which germination of at least 50% of viable seeds ceased. Base temperatures were lowest for L. perenne and Zea mays at 3.4 and 4.5 °C respectively; for different Miscanthus half-sib families base temperatures ranged between 9.7 and 11.6 °C and these were higher than maize and switchgrass which share CSUB4/SUB photosynthesis with Miscanthus. Parameters derived from germination and temperature were used to predict germination patterns in Europe based on historical climate data. We predict that seed establishment of Miscanthus in spring time is unlikely to be viable in Northern Europe under present climatic conditions without crop management practices aimed at raising soil temperature, and that useful variation in thermal requirement for germination in Miscanthus is available which should facilitate seed germination in other regions.