Australasian Science: Australia's authority on science since 1938

Sex without Seed

Mouse-ear hawkweed can clone itself through its seeds.

Mouse-ear hawkweed can clone itself through its seeds.

By Dyani Lewis

Plant biologists are finding ways to retain hybrid vigour in important crops by generating clonal seed.

Dyani Lewis is a freelance science writer.

The full text of this article can be purchased from Informit.

On the alpine slopes of New Zealand’s South Island, an innocuous-looking yellow flower, not dissimilar to a daisy in appearance, has invaded the terrain. A native of Europe and the central Asian steppe, mouse-ear hawkweed (Hieracium pilosella) has successfully colonised disturbed landscapes around the globe, contaminating pastures and out-competing native plants for ecological real estate. In New Zealand, Australia and many states of the US, it is classified as a noxious and invasive weed.

As much as hawkweed may be the scourge of pastoralists and environmentalists, some biologists are eagerly studying hawkweed to unlock an important quirk of its reproduction. Hawkweed’s allure comes from its ability to clone itself. Many plants can be propagated through cloning – grasses send out runners, and many others are helped along by gardeners carefully tending cuttings. But hawkweed’s trick is to clone itself through its seeds – a phenomenon known as apomixis – and this has caught the attention of scientists.

Plant breeders spend many years crossing varieties and looking for the next elite plant that will give them an edge against their competitors and the environment. Breeding is a vital weapon in the arms race agriculturalists are engaged in against viral and fungal pathogens. It can also increase crop yield, tolerance to drought and frost, and improve texture,...

The full text of this article can be purchased from Informit.