A BREED APART
Kate Marshall looks at the work of some of New Zealand’s most successful fruit tree breeders.
New Zealand punches above its weight in the development of new fruit varieties. It is astounding the number of world-leading varieties that have been developed here by both government and private breeding programmes.
This is noteworthy as importing new plant material into this country is difficult and time consuming, requiring a quarantine period to test for diseases, pests and viruses.
Although the process of developing new fruit tree varieties is pretty lengthy too. It can take thousands of rejections and many years before the breeder finds a winner.
The main sources of new fruit varieties are seedlings and natural mutations. Seedlings can be accidental, called “chance” seedlings, or result from the controlled crossing of two varieties. Natural mutations are usually just one branch which is different to the rest – the fruit may be redder, say, or have a slightly different maturity time.
Plant breeders aim for a set of desired characteristics such as bigger fruit, better storage, improved flavour, disease resistance, different maturity time or a smaller tree habit.
Sometimes a fruit tree that’s a new variety costs more (although usually only a few dollars more than the older varieties). But that is not much when you consider the time and resources invested by the breeder, with at least 10 years of trials, rejects and development to get to a single new cultivar.
How does it happen? Chance seedlings
are those which are found in the wild or grown without selecting the parentage.
Controlled seedlings are where two varieties are selected, with at least one desirable characteristic each. The flowers on the mother plant are pollinated with pollen from the other variety, in a controlled way. Methods of crossing differ with each crop, but in general, the flower’s male parts are covered, and a scalpel is used to emasculate the female parts of the flower, which are then hand pollinated with pollen on a small brush. The flower is then covered with a bag for a few weeks to keep out other pollen.
Synchronising the male and female flowers so the pollen is at its best, and the female receptive, is important.
The seeds from the resulting fruit are raised, then planted out for evaluation. Each seed holds a different genetic profile, and so is a slightly different combination of the characteristics from the parents.
Once a promising seedling has been identified, the next stage begins with further trials. Trial trees are usually placed in orchards (and home gardens) in a few regions to see how the variety performs in different climates. After several years of cropping, the trial information is evaluated to see if the variety is worth pursuing or not.
If the go-ahead is given, the next stage of the process is increasing the amount of plant material, as there may be less than 10 trees of the variety in existence. From these 10 trees, several hundred trees can be produced. Then from these, several thousand can be grown in the nursery, with this process alone taking three to four years.
Once the decision has been made to commercialise a variety (or to bring it to market), the process of intellectual property protection begins. Plant Variety Rights (or PVR) are like a patent for a plant, and means that the variety is new and distinct from anything else already available. PVR protection lasts for 23 years, ensuring the flow of royalties from the nursery to the breeder for each plant sold during that time.
John McLaren In Earnscleugh, Central Otago,
John McLaren started his plant breeding career with apricot varieties at the government’s Department of Scientific & Industrial Research (DSIR), trying to breed in resistance to bacterial blast. (DSIR went on to become HortResearch, and is now known as Plant & Food Research.)
He worked closely with the Lincoln University crop research division, crossing ‘Moorpark’ and ‘Sundrop’ to create over 6000 apricot seedlings, which were then culled to several hundred promising selections. From these, the outstanding ‘Cluthagold’, ‘Cluthasun’, ‘Cluthalate’ and ‘Cluthaearly’ were released in the early 1990s.
‘Cluthagold’ remains a popular commercial variety for Central Otago fruit growers. “There were some absolute dogs, but you have to do the seedling work, as you cannot predict the results,” John says.
John developed an interest in apple varieties after working in Nelson
“Breeding is a mix of science and art. You need to really like and believe in the crop you are working with.”
orchards while at university. So after leaving DSIR, he set up a private breeding programme with some funding from a French company. Several major commercial apple varieties have been released from this programme, including elongated red apple ‘Sonya’ and the Thumbelina series of bite-sized apples ‘Candy Crunch’ and ‘Golden Crunch’ for home gardeners. There is a possible release of a very shiny red apple variety for home gardeners soon.
But it’s not just fruit varieties that John is interested in. With Denis Hughes at Blue Mountain Nurseries in Tapanui, John has released new crabapple variety ‘Flamingo’, which has double red flower buds opening to deep pink blooms, with burgundy red foliage on an upright tree. Waimea Nurseries has also released a thornless type of Robinia ‘Frisia’ bred by John, called ‘Tropical Splash’.
Further releases in the pipeline include a pittosporum, coloured willows and a yellow crabapple. “With breeding taking from 10 to 15 years from the seedling, and released variety taking around 15 years, breeders need to live for 300 to 400 years to be really successful!” he quips.
Roy Hart Like John, Roy started plant
breeding with DSIR. He worked on breeding swedes, turnips, rape and chou moellier (kale) for improved disease resistance. He then moved onto breeding cereal crops in Southland, before the drawcard of a warmer climate at the Riwaka Research Station took him north.
The focus at Riwaka was fruit breeding to replace the local mainstay crops of tobacco and hops. One of these crops was feijoa, and Roy was the breeder of the popular varieties ‘Pounamu’ and ‘Kakapo’.
Roy says that he wanted to continue with horticultural work after retiring. “As the research organisations had stopped feijoa work, I decided to continue it,” he explained.
Since his official retirement, Roy has been active in plant breeding, producing the outstanding early ripening feijoa varieties ‘Anatoki’ and ‘Kakariki’, which bring forward the season by about a month – great for both home gardeners and commercial growers alike. In addition to its early ripening nature, the fruit is extremely sweet and very large.
Not done yet with feijoas, Roy is producing around 400 seedlings a year which are planted in orchards around Nelson, with several selections looking very promising for possible future release after further trials.
He has also developed an outstanding plum variety called ‘Lucy’ (‘Luisa’ crossed with ‘Fortune’),
disease-resistant apples and an apricot variety which is being trialled. A keen member of the New Zealand Tree Crop Association, Roy has recently become interested in honeyberries ( Lonicera caerulea), also known as haskaps.
As the sole worker in his breeding programme, Roy grows about 400 seedlings a year. The seedlings take about three to four years from seed to the first fruit, and are assessed for another three to four years. “Breeding is a mix of science and art. You need to really like and believe in the crop you are working with,” he says. “Also, you need a crystal ball to know what will be needed in six to 10 years’ time. One of my trials involving a nut crop reached a cropping stage, only for me to discover there was no market for them in New Zealand.”
Plant & Food Research The government- and industry-funded
breeding organisation is currently working on new cultivars of apples, pears, kiwifruit, berryfruit and summerfruit. As part of its international aid and development work, PFR is also working on dragonfruit.
Communications manager Emma Timewell says that the breeding focuses on traits desired by consumers such as taste, flavour, novel colours and characteristics as well as those required by growers including yield, pest and disease resistance, and fruit size.
Environmental requirements – including the ability to grow in multiple locations in New Zealand – are also considered.
The ability for new fruit cultivars to handle the produce supply chain in terms of storage and robust handling qualities are also important from a commercial perspective.
Fortunately, many of the characteristics required by home gardeners are the same as those that appeal to commercial growers and consumers. These qualities include yield, pest and disease resistance as well as taste.
There is a big range of varieties bred by PFR which are available to home gardeners. This includes blueberry varieties grown by Incredible Edibles (‘Blue Dawn’, ‘Blue Magic’, ‘Island Blue’ and ‘Muffin’); feijoas (‘Opal Star’, ‘Apollo’ and ‘Unique’); the KiwiApples series of dwarf trees; ‘Cluthaearly’ and ‘Cluthalate’ apricots; ‘Scarlet O’Hara’ and ‘Coconut Ice’ white-fleshed peaches; and the Sciros apple variety (better known as Pacific Rose).
To develop new cultivars, PFR uses traditional breeding techniques to select and control crossing of the best parents to deliver the combination of desired traits.
Once these seedlings have been grown, the genomics research (undertaken in containment) helps to identify the best parents for crosses and select seedlings at the early stages – without having to wait a number of years to evaluate the fruit produced from these seedlings.
Despite this use of gene technology to speed up the breeding process, it typically still takes 10 to 15 years from crossing to release of a commercial cultivar. Tens of thousands of seedlings are raised and evaluated each year across their fruit breeding programmes.