Reciprocal transplant experiments testing the performance of common and early flowering types of Imperata cylindrica in Japan

摘要

We performed reciprocal transplant experiments in Miyazaki, Kyoto, and Akita to differentiate the effects of environmental factors and genetic variations on biomass production and heading time in common (C-) and early flowering (E-) types of Imperata cylindrica. In our experiments, we used 10 and 11 accessions of the C- and E-types, respectively, collected across the distribution range of the two types in Japan. Three ramets for each accession were potted in each of the experimental fields and cultivated from June 2016 through November 2017. All accessions were grouped based on their origins: low-latitude group (LG), mid-latitude group (MG), and high-latitude group (HG). The biomasses of the C-types in the MG were heavier than those of the C-types in the LG and HG in all experimental fields. E-type accessions with origins close to the respective experimental fields tended to have higher biomasses than accessions collected further away. C-type plants grew more vigorously than E-type plants in Miyazaki and Kyoto, but biomass growth was similar between the types in Akita. Thus, we did not detect clear local adaptation measured as biomass production in the C-type. However, each accession of the E-type appeared to be locally adapted. The competitive abilities of the C- and E-type accessions from Tohoku were similar. The flowering periods of the two types did not overlap in any of the experimental fields. Hence, although wild crosses between the two types occur in Tohoku, between-type hybridization was improbable under the conditions of our common garden experiment.