Breeding and Mating Systems of Australian Proteaceae

Abstract

There has been a significant increase in the number of studies investigating plant breeding and mating systems over the past 10 years. The family Proteaceae, in particular, has dominated such research conducted in Australia. Thus it is now timely to present a critical review of the breeding and mating systems of the Australian Proteaceae. It is hoped that this will stimulate further research. The review covers key events between pollen deposition on stigmas through to fruit set. The genus Banksia, although not the most diverse of the family, has received a disproportionate amount of attention. It has featured in nine published studies of self-compatibility compared to 13 studies spanning the other 45 genera and has featured in eight genetic studies of the mating system compared to just two on other genera. Few studies have assessed the timing of stigma receptivity despite the intriguing situation in most Proteaceae of auto-deposition of self-pollen on or near stigmas at anthesis. Studies suggest that stigmas are not receptive until 0.5–4 days after anthesis. Banksia species appear to show low levels of self-compatibility although one subspecies shows high levels of selfing and evidence of selective fruit development. Self-compatibility may be more common in other genera, although a dearth of studies precludes generalisation. Assessment of mating systems indicates almost complete outcrossing for most species, lending support to the idea of selective fruit development. It is clear that many further studies of all topics are required but particularly across a wide range of genera because many have not been studied at all.