Two decades of searching for the best
Apricot growers are lining up to plant new varieties developed at Plant & Food’s Research station near Clyde where apricot breeder Arlene Nixon has spent nearly 20 years searching for the perfect fruit.
New cultivars have been planted in trial blocks in Central Otago orchards and the outcome of these will be new varieties for consumers to enjoy… soon. New cultivars were bred using conventional breeding methods as Arlene and her team take over the role of the bees and fertilise bloom on selected trees to develop populations of seedling trees.
Breeding new varieties of fruit is a long process and one which Arlene, a Canadian who came from a background in animal breeding, is passionate about. Her 20-year anniversary will be in February next year but she will always be searching for a new apricot, even though she has found some that New Zealand consumers will enjoy. She believes she’s looked at thousands of possible trees over the years.
When an Asian buyer visited one of her trial blocks at the Plant & Food Research station Arlene pointed out her three top choices. He did a tasting. It was a little like Goldilocks with him trying the one in the middle, the one on the left and the one on the right. And his choice of the one on the right demonstrated that Asian consumers can have a different palate to New Zealanders.
As potential cultivars go into an elite stage of testing, consumer trials are added to discern those that may be best suited to future markets. Arlene said she always remembers this when selecting cultivars to go out to growers.
Storage trials, funded by SummerfruitNZ, test some of the late maturing advanced selections for long storage and ethylene production. These trials investigate the rate at which apricots naturally produce ethylene and are an indicator that fruit could potentially be shipped to foreign markets.
“I have a shopping list for the characteristics I’m looking for during the selection process and this involves looking at it from the commercial angle for the growers,” she said.
“I have a shopping list for the characteristics I’m looking for during the selection process and this involves looking at it from the commercial angle for the growers.”
“There are a lot of characters, such as flavour, sugar acid, appearance, tree health and tolerance to handling, add up to the tree being commercially viable. The growers want to grow a good piece of fruit, and naturally they have to be able to profit from their efforts.
“Consumer attributes are very important and the key to repeat purchasing. The aim of the programme is high quality full-flavoured apricots of good size, with eye-appeal, high colour, smooth skin, shine, shape symmetry and with incredible flavours.”
Picture this… each day of the blossom season an apricot “mother” tree ready to burst into bloom is surrounded by workers beneath its branches carrying out handpollination. Individual blossoms at the “popcorn” stage are carefully opened, the little petals removed and the anthers removed. The female parts are now ready to be hand pollinated with golden pollen from a parent tree.
During the Sumptuous Summerfruit programme four workers per tree were working quickly, some with a pair of tweezers, to dab pollen on each blossom before a blossom opened naturally. Each branch of each tree could have different pollen applied in order to have enough crosses to capture the best attributes of Plant & Food’s
collection of apricot trees.
Both parents have been carefully chosen for the
attributes they can contribute to the programme.
A few weeks earlier the pollen was carefully combed from blossoms forced to bloom early in the laboratory. This is performed with the use of a nit comb which is used to carefully tease the anthers from freshly
When all possible blossoms – potentially thousands per tree have been covered – the tree is covered with a plastic tent and a propane heater is used to keep the frost away. This pattern is repeated day after day until all required “mother” trees have been
The trees are not thinned as each fruit contains a
seed that could become the next new cultivar. The apricots grow, ripen and are harvested. Stones are collected for growing on in glasshouses in Hawke’s Bay Research Centre.
More than 4000 stones may have been collected but after growing the trees and evaluating the fruit, only two or three trees may have what it takes for a new cultivar. The seedling trees are returned to Central Otago in spring when they measure about 30cm in height. Once the trees fruit Arlene walks the blocks daily searching for seedlings with the potential to become another commercial release or contribute to the breeding programme.
“A grower needs a healthy tree that crops well and produces high quality fruit which will go over the grader without scuffing and also handle shipping,” she said.
“It needs to have storage capability in order to reach the market-place and still have some shelf-life.”
Apricot trees require chilling in order to set fruit. This is not a problem in Central Otago, where lower temperatures ensure plenty of buds, but is more of a challenge in the North Island where low chill apricot trees are required.
While trees with less chill will fruit, these are often not of the same high quality as high chill apricots.
“Breeding a high quality, low chill apricot is another of our breeding goals and a very important one, as the first fruit of the season can set a consumer’s buying habits for the season,” she said.
“If a consumer has a bad eating experience they may not repeat purchase for over a month. We need to give the consumer a great eating experience right through the season, starting from that first apricot they purchase and so they continue to buy apricots.
“Luckily North Island growers are very aware of this and very supportive of efforts to breed low chill varieties.”
Back in 2011 Arlene told growers at a Summerfruit Conference that a new cultivar MacKenzie 12/45 had stunning flavour and she saw the possibilities of using this as a parent. But she stressed that advanced material needed several season of evaluations before decisions could be made regarding its release as a new cultivar. Now this MacKenzie seedling has made a big impact on seedling blocks at Clyde and had been named NZ Summer 2.
Over the years many generations of seedlings have been evaluated and the most promises have been budded on to Golden Queen peach rootstocks for further evaluation as advanced selections.
“We are at the stage now of working through the material generated from the crosses we did several years ago,” she said.
“The seedling blocks are mostly gone and a large block of advanced selections is being evaluated for commercial suitability.”
Long storage is one of the goals of the breeding programme. Dr Jill Stanley and her team have been looking at ethylene production in apricots. Apricots are a fruit which produces this gas naturally and its presence signals softening and ripening.
“Some of the new apricots produce very little ethylene so do not soften as much as older varieties during the ripening process which means they store longer enabling apricots to be shipped to foreign markets and still offer a good eating experience,” Arlene said. Another of the cultivars developed from the original MacKenzie block is NZSummer 4, an early harvest, domestic apricot, harvested in early to mid-December in Clyde.
The search for late harvest varieties of perfect fruit with crunch, apricot flavour, high brix levels, red blushed, bright colour high colour and long storage is ongoing.
The programme’s newly released cultivars, bred more than 10 years ago, are now being planted in grower orchards so should be available on domestic markets over the next few years.
Consumers will be in for a treat, Arlene believes.
“It’s all exciting isn’t it?”
Apricot breeder Arlene Nixon has a shovel at the ready to plant a seedling cultivar bred at Plant & Food Research, Clyde.
One of the McKenzie new cultivars. Image credit: Plant & Food Research New Zealand
Apricot stones, a tube and a sprinkling of golden pollen used in the search for new apricot varieties at Plant & Food Research Orchard at Clyde.