DNA fingerprinting supports hybridisation as a factor explaining complex natural variation in Phormium (Hemerocallidaceae)

Abstract

Analysis of AFLP profiles from 47 wild‐sourced plants of Phormium from New Zealand and Norfolk Island reveals two major genetic groups corresponding with the two currently recognised and sympatric species (P. cookianum and P. tenax). In addition, plants from a number of coastal sites, a putative F₁ hybrid, and some plants identified a priori as P. cookianum display AFLP profiles consistent with a hybrid origin. These putative hybrid plants have varying genomic composition, and some were collected from morphologically uniform populations. Others depart from the intermediate morphology expected of F₁ hybrids. Therefore, introgression between P. cookianum and P. tenax and the existence of stabilised hybrid derivatives appears likely. Some degree of geographic structuring of genetic diversity is evident in both species.

Keywords:

• Phormium tenax
• P. cookianum
• P. “Coast”
• AFLP
• hybridisation
• New Zealand flora