Genetic Diversity, Cytogenetics, and Biomass Yields among Arundo spp. and Accessions (Arundineae)

Genetic diversity and cytogenetics of 31 accessions of Arundo spp., collected from North America and South Asia, were characterized using 20 ISSR markers, flow cytometry and cytology. In addition, field trials of 23 Arundo donax accessions were established in 2011 and harvested annually in winter from 2012 to 2013 to assess biomass yields. Cluster analysis (UPGMA) based on Jaccard’s similarity coefficient clearly differentiated Arundo formasana from Arundo donax and a third unidentified Arundo taxa.  Arundo donax further contained two subgroups representing North American and South Asian accessions. Within each Arundo donax subgroup, genetic distances were low but showed discernable variation (0.03 for North America, 0.07 for South Asia). Principle coordinate analysis further supported distinct clusters and variation within clusters. Relative genome sizes were determined using Pisum sativum as the reference genome and DAPI fluorochrome. Chromosome numbers (2n), ploidy levels, and 2C relative genome sizes ranged from 67 to 105, hexaploid to enneaploid, and 2.78 to 4.13 pg, respectively, and were similar within each taxa/subgroup.  While there was a low level of genetic variability among Arundo donax accession, dry biomass yields varied significantly ranging from 22 to 65 Mg ha^-1 y^-1 for the third growing season.