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)

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 C4 photosynthesis
has tropical origins, but is found growing both at high latitudes (4401) and altitudes
(41000 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 1C on a 12 h cycle and germination was monitored
daily for 35 days at mean temperatures ranging from 5.3 to 26.5 1C. 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 1C respectively; for
different Miscanthus half-sib families base temperatures ranged between 9.7 and 11.6 1C
and these were higher than maize and switchgrass which share C4 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.