In a forestry block all of the trees look the same. There’s a reason for that – they probably ARE all the same. Forestry has used clonal propagation for years, because they want trees that grow exactly the same way; the genetic variation that comes with normal cross pollination and fertilisation would deliver less uniform growth, make harvesting more time-consuming and therefore expensive.
The same is true of kiwifruit orchards, apples and grapes: once you have a plant that delivers exactly what you want, cloning it will deliver that same optimal performance. But most of that optimal genetic material – the germplasm – is stored out in the field … it’s in working orchards and vineyards all over the country.
That means that our prime horticultural stock is vulnerable to disease and climate fluctuations. The PSA crisis showed the dangers of this, and a number of scientists are working on ways to preserve valuable germplasm using cryopreservation technologies.
David Burritt in the Botany department has spent years working on clonal propagation and cryopreservation. Now that clonal propagation is established for many commercially important plant species, he is working, in collaboration with scientists from Plant and Food, to understanding how plants can survive freezing and to increase cryopreservation success rates.
“This is the other side of seed banks as a repository of plant genetics. Seeds have that cross-pollination variability, which is valuable for preserving diversity. But cryopreservation protects those plants that are so important to our horticulture; the exact genotypes of kiwifruit, apples, grapes, and forestry trees that are critical to New Zealand’s exports.”
Cryopreservation techniques are improving all the time, making our valuable horticultural stock more secure.