New commercial varieties of kiwifruit optimised for their flavour, colour and health attributes will become available in the next few years, thanks to the publication of a huge collection of DNA sequences from the fruit.
Kiwifruit belong to the genus Actinidia. The two best known cultivars are the Haywood and the Zespri Gold kiwifruits – but given the diversity of the genus there is scope to develop many more, with tailored attributes.
Now fruit breeders will be able to more closely tailor new fruit varieties to consumer tastes and market needs, as the collection of 130,000 DNA sequences put together by New Zealand’s Hort Research and its biotech partner Genesis Research and Development Corporation over the last eight years have been made public.
Details of the discovery and analysis sequences – called expressed sequence tags, or ESTs – have been published in the journal BMC Genomics.
The ESTs come from active genes in the plant that govern characteristics like flavour, colour, shape, and vitamin content – as well as practical properties like ripening and storage time.
They will be invaluable to breeders seeking to develop new varieties of the fruit using Marker Assisted Selection (MAS), since it will allow them to identify the genes they are looking.
In its own right, MAS has significantly speeded up the fruit breeding process since it removes the need to wait for seedlings to bear fruit before their properties can be assessed and either commercialised or cross-bred.
“If breeding a new fruit with a specific trait is like finding a needle in a haystack, then MAS is like having a metal detector,” said Dr William Laing, a scientist with HortResearch.
“With MAS, we can quickly scan the seedlings and find out right away which ones are likely to have the type of fruit we want.”
HortResearch actually breeds kiwifruit exclusively for Zespri and the New Zealand kiwifruit industry, and has a collection of 23 species. Zespri, for its part, manages some 30 per cent of internationally traded kiwifruit. It represents some 4000 kiwifruit growers globally, and sells more than 34,000 tonnes of the fruit around the world each year.
The commercialised fruits are already enjoyed by consumers in their whole form, and on the back of their popularity food manufacturers are also developing products that use kiwi or kiwi flavour.
In the last five years, market researcher Mintel has listed 197 new food products (mostly confectionery and yoghurts) in its Global New Products Database.
This is not the first time that HortResearch and Genesis, which has a therapeutic platform focused on immunity and cancer, have released DNA data that they have collected to aid the development of new fruits.
In 2006 they made public some 50,000 apple ESTs, which are now being employed by Hort in its apple- and pear-breeding programme.
BMC Genomics 2008, 9:351
Title: “Analysis of expressed sequence tags from actinidia: applications of a cross species EST database for gene discovery in the areas of flavor, health, color and ripening”
Authors: Ross N Crowhurst, Andrew P Gleave, Espeth A MacRae, Charles Ampomah-Dwamena, Ross G Atkinson, Lesley L Beuning, Sean M Bulley, David Chagne, Ken B Marsh, Adam J Matich, Mirco Montefiori, Richard D Newcomb, Robert J Schaffer, Bjorn Usadel, Andrew C Allan, Helen L Boldingh, Judith H Bowen, Marcus W Davy, Rheinhart Eckloff, A Ross Ferguson, Lena G Fraser, Emma Gera, Roger P Hellens, Bart J Janssen, Karen Klages, Kim R Lo, Robin M MacDiarmid, Bhawana Nain, Mark A McNeilage, Maysoon Rassam, et al.