Genetic diversity and relationships in native Hawaiian Saccharum officinarum sugarcane.

Commercial sugarcane hybrid cultivars currently in production are high-yielding, disease-resistant, millable canes and are the result of years of breeding work. In Hawaii, these commercial hybrids are quite distinct from many Saccharum officinarum canes still in existence that were brought to the islands and cultivated by the native Polynesians. The actual genetic relationships among the native canes and the extent to which they contributed to the commercial hybrid germplasm has been the subject of speculation over the years. Genetic analysis of 43 presumed native Hawaiian S. officinarum clones using 228 DNA markers confirmed them to be a group distinct from the modern hybrid cultivars. The resulting dendrogram tended to confirm that there were several separate S. officinarum introductions that, owing to selections of somatic mutations, diverged into a number of cluster groups. When the "Sandwich Isles" were discovered by Captain James Cook in 1778, the Hawaiians were found to be growing sugarcane, S. officinarum ( Cook 1785). Sugarcane (ko, in the Hawaiian language) appeared in a variety of stalk and leaf colors, often with stripes (the "ribbon canes"). In the interest of preserving this historic germplasm, a collection was assembled in the 1920s by Edward L. Caum of the Hawaiian Sugar Planters' Association and W. W. G. Moir of American Factors. Histories and descriptions of the canes were reported by Moir (1932).