Molecular markers and experimental pollinations reveal self-fertility and high levels of natural inbreeding in the New Zealand endemic tree Vitex lucens (puriri)

Abstract

The breeding system of the New Zealand endemic tree Vitex lucens (puriri) (Labiatae) was investigated using controlled pollinations and paternity analysis with RAPD and microsatellite markers. Experimental pollinations demonstrated that puriri is physiologically capable of producing fruit and viable seed from both selfed and outcrossed flowers. A low level of autogamous seed set was also observed, suggesting that at least occasional seed set is possible in the absence of pollinators. Polymorphic RAPD and microsatellite markers were developed for puriri and used to confirm the parentage of seedlings from experimental self and outcrossed pollinations. Paternity analysis of 18 seedlings from naturally pollinated drupes collected from a single tree revealed that a high proportion of these progeny were likely to be the result of self-pollination. These results are the first demonstration that puriri is capable of both self-and cross-fertilisation, and that in nature puriri has a mixed breeding system, with high levels of self-fertilisation possible. The molecular markers developed in this project will be useful tools for future puriri genetic studies.