Russell Lowe and the saving of the kiwifruit industry

Scientist Russell Lowe has been introduced to Stuff readers as “the man who saved New Zealand’s billion-dollar kiwifruit industry from disease”.

The article, written by journalist and author Nicky Pellegrino, says it is no exaggeration to say that kiwifruit have been Russell Lowe’s life.

For more than 50 years as a plant scientist, the New Zealand scientist has been devoted to the little green, gold and now red fruits formerly known here as Chinese gooseberries.

But his contribution was perhaps best summed up when he was presented with the Plant Raiser’s Award by the Royal New Zealand Institute of Horticulture last year.

In a speech when he was presenting the award, RNZIH president Dr Keith Hammett said Lowe was widely considered to have saved New Zealand’s entire kiwifruit industry after it was devastated by the virulent bacterial disease PSA (Pseudomonas syringae pv. actinidiae).” Continue reading

Successful funding bids set to identify kiwifruit plant stress and optimise forestry yield

Scientists from Tauranga’s PlantTech Research Institute are celebrating their involvement in two successful funding bids to the Ministry for Business, Innovation & Employment’s (MBIE) Endeavour Fund, New Zealand’s largest contestable research fund.

In this year’s round of funding, 69 new scientific research projects were awarded more than $244 million.

Tauranga headquartered PlantTech Research Institute is leading a two-year international project, that will use airborne remote sensors to discover what is causing plant stress in kiwifruit orchards, thanks to a successful bid for $1 million.

Another MBIE-funded project, led by Scion, Seeing the forest for the treestransforming tree phenotyping for future forests, involves using PlantTech’s capability in hyperspectral imagery analysis to support research that will identify the best genotype to plant in different environments for commercial production and indigenous uses. Continue reading

Deadline extended for input on kiwifruit spray ingredient

The deadline has been extended  for submissions on the potential phase-out of hydrogen cyanamide, an active ingredient in sprays commonly used by kiwifruit growers.

The original deadline of 26 November has been pushed out to 5pm on Monday 20 December.

Hydrogen cyanamide is banned in Europe, and its re-registration is currently under review in the United States.

In New Zealand, the Environmental Protection Authority (EPA) is undertaking a reassessment of the substance, which is primarily sprayed on bare kiwifruit vines to help buds form after winter.

The latest evidence suggests the economic benefits of hydrogen cyanamide are outweighed by the environmental risks and adverse health effects to the reproductive system and thyroid. Continue reading

EPA seeks views on potential phase-out of kiwifruit spray ingredient

Public consultation is open on an application to reassess the use of hydrogen cyanamide, an active ingredient in sprays commonly used by kiwifruit growers.

Hydrogen cyanamide is banned in Europe and its re-registration is under review in the United States.

In New Zealand, the Environmental Protection Authority (EPA) is undertaking a reassessment of the substance, which is primarily sprayed on bare kiwifruit orchards to help buds form after winter.

“While we accept that there are economic benefits from hydrogen cyanamide use, new information suggests these are outweighed by the environmental risks and adverse health effects,” says Dr Chris Hill, General Manager of the EPA’s Hazardous Substances group.

“As part of our reassessment of this substance, we’ve carried out an initial assessment of the information now available and produced draft recommendations. Continue reading

Designing plantings to boost pollination in kiwifruit

New native plantings have been established in the Bay of Plenty to support kiwifruit pollination and encourage bio-diversity.

The plantings of 600 trees and shrubs on previously low-productivity land include a carefully selected mix of plants that support insects known to pollinate kiwifruit, while reducing the risks of harbouring pest species, mainly passion vine hopper.

Based on Plant & Food Research science, the project is funded by Operation Pollinator®, a Syngenta global initiative to boost the number of pollinating insects on commercial farms. It is expected that the effect of the new plants will increase as the plants establish, grow, and start to produce flowers.

The research team hopes to monitor changes in insect populations and kiwifruit yields during this period.

While restoring natives to production landscapes has become an increasingly common practice in New Zealand, this is the first project of its kind to take a prescriptive approach to enhancing pollination and avoiding creating a reservoir for pests in kiwifruit.

“If you want to stabilise a streambank, or return nitrogen to the soil, we know certain native plants can do that”, says project leader Dr Brad Howlett from Plant & Food Research. “We want to take the same approach for enhancing crop pollination by managing the landscape.”

Dr Howlett’s team worked for several years to get a clear picture of which insects, including native bees, flies, and beetles are the most important for kiwifruit pollination. To be good pollinators, the insects must visit kiwifruit flowers and  transfer sufficient amounts of pollen between male and female flowers.

Once researchers identified the most important pollinators, they surveyed native plants to learn which of these were important for the best pollinators.

“The plantings that were established this year include plant species which we know kiwifruit pollinators use during their life cycle and, importantly, these plants flower at different times to kiwifruit. This will support large populations of pollinating insects ready to move onto the crop during flowering,” says Dr Howlett.

The kiwifruit industry is entirely dependent on pollination, and relies heavily on managed honey bees and manual pollination to ensure that flowers set fruit. Human pollination (either by hand or vehicle-based) can be expensive, and access to honey bee hives can be limited because of overlap with Mānuka honey collection and concerns about the effects of crop-protecting nets on colony health.

Increased support for native insects should help to reduce concerns about pollination in this high-value crop.

Source:  Plant & Food Research

Scientists are cracking the code to kiwifruit pollination success using a “digital twin”

Plant & Food Research scientists and collaborators from the USA have compiled more than 30 years of field-based data from kiwifruit research to create “digital twins” of pollination processes in kiwifruit orchards, and have used these to predict how growers can optimise their fruit set.

Digital twins are virtual replicas of physical systems – in this case mathematical models of the biology of the plants and the behaviour of pollinating bees.

These digital twins give researchers the ability to examine complex scenarios which examine multiple, intertwined factors at once. These types of trials are difficult or impossible to test in field – running a full combination of even six variables would require more kiwifruit orchards than exist in New Zealand. Continue reading

Cold temperature survival of an unwanted pest of kiwifruit

Researchers report in The New Zealand Journal of Crop and Horticultural Science on the survival of White Peach Scale on kiwifruit imported into New Zealand.

Believed to have originated in continental Asia, White Peach Scale (WPS), Pseudaulacaspis pentagona, is an armoured scale insect pest of fruit and ornamental trees. It has a global distribution in major crop producing and exporting countries, excluding New Zealand.

In Italy, WPS has become a serious pest of kiwifruit, infesting all above-ground parts of the plant.

Kiwifruit is imported from Italy to New Zealand in summer each year and live WPS have been found on the imported fruit. With increasing vol Continue reading

Kiwifruit genes validate plant evolutionary theory

An international research team has discovered a sex-determining gene in kiwifruit that could potentially lead to the breeding of hermaphrodite varieties. The study has also validated the “two-mutation model” in sex acquisition of plants proposed 40 years ago.

Plant & Food Research scientists and their research partners in Japan and the US have identified a gene called Friendly Boy (FrBy), which is necessary for pollen production and is found naturally in Y chromosomes of male kiwifruit plants. It is the second sex-determinant discovered in kiwifruit after Shy Girl (SyGI), which suppresses fruit production in male kiwifruit plants. Continue reading

Novel plant architectures and canopy management techniques bear fruit

Novel plant architectures and new canopy management techniques have nearly doubled the yield of Envy™ apples and improved the quality of Zespri® SunGold Kiwifruit.

A Plant & Food Research team in Hawke’s Bay have optimised canopy management and tree architecture of the ‘Scilate’ cultivar, marketed as Envy™ apple, to enhance the efficiency of plant function and drastically increase the harvest index (the amount of fruit dry weight produced relative to the total dry weight of a tree).

They applied artificial spur extinction, a chemical-free crop load management technique, on trees to reduce the number of floral buds in winter in order to better allocate carbohydrate and nutrients during growth to the fruit bearing spurs. Continue reading

Climate change could render kiwifruit capital fruitless

As global temperatures rise with climate change, the risk of insufficient winter chilling for kiwifruit grown in Te Puke increases. This spurs a need for thoughtful planning from the industry to ensure the sustainability of kiwifruit in New Zealand.

These matters are examined in ‘Potential impact of climate change on Hayward kiwifruit production viability in New Zealand,’  by Andrew Tait, Vijay Paul, Abha Sood and Alistair Mowat features in the latest issue of New Zealand Journal of Crop and Horticultural Science Volume 46.3.

The article cautions that production viability of the Hayward kiwifruit is set to decrease steadily over the coming years. The model used shows the Hayward kiwifruit industry in Te Puke becoming non-viable by the end of the century under all but the strictest of global greenhouse gas emissions pathways.

The kiwifruit industry is predicted to contribute $6.14 billion to New Zealand’s gross domestic product by 2030. More than half of Aotearoa’s kiwifruit crop is grown in the Bay of Plenty, including the popular Hayward kiwifruit cultivar predominantly in Te Puke township, just southeast of Tauranga.

The town of Te Puke in the Western Bay of Plenty is one of the world’s kiwifruit hot-spots. In addition to the enormous fibreglass Kiwifruit straddling the roadside of SH2 into the town, Te Puke is proud to boast the title of ‘Kiwifruit capital of New Zealand’.

The climate and soils of Te Puke have historically been well-suited to growing kiwifruit as it sits within an ideal temperature range, has good winter chilling, warm springs, and mild summers and autumns. When you add lots of hours of sunshine and just the right amount of rain on deep, free-draining volcanic soils, it creates the perfect environment for growing bounties of fresh, tangy and sweet kiwifruit.

As global temperatures rise with climate change, this idyllic kiwifruit environment in Te Puke could be severely altered by the middle of the century. Commercial viability of the industry in the area could dwindle to nothing by 2080.

The use of the chemical hydrogen cyanamide (known commercially as Hi-Cane) greatly enhances the long-term viability of kiwifruit production in Te Puke. The use of Hi-Cane encourages budbreak and boosts the number of fruit on vines. It can also substitute about 2⁰C of winter chilling benefit in warm winters (basically the natural budbreak will yield the same number of flowers as untreated vines in a winter that is 2⁰C colder). Concern from the community regarding the toxicity and environmental effects of Hi-Cane mean that its use is increasingly being restricted or banned.

The possible banning of Hi-Cane spraying means there is an urgent need to consider other areas in the country for kiwifruit production, alongside possible genetic improvements to kiwifruit cultivars (for example, introducing low winter chill requirement traits). Other advancements made by growers to mitigate climate change in their vine management practices (like plant breeding) and some other factors which determine kiwifruit viability have not been included in the model discussed in the study.

The aim of the study was to develop a simple model for assessing current and future Hayward kiwifruit production viability in Te Puke, drawing on a wealth of previous research on the topic. The relative simplicity of the model ensures that it is easy to use with simulated temperature data output from climate models, and is easy to understand and interpret.

From this study it appears Te Puke’s perfect climate for kiwifruit orchards is set to change alongside global warming. However the authors conclude there are many other areas in New Zealand that show a potential increase in kiwifruit production viability over the next century.

Such areas include more inland parts of the Bay of Plenty and colder places like Canterbury and Central Otago. Through good future planning, the fruitful New Zealand kiwifruit industry is very likely to remain viable for many decades to come.

* The article ‘Potential impact of climate change on Hayward kiwifruit production viability in New Zealand‘ is available to read in full at Taylor & Francis Online. Articles included also discuss the effects of low pressure storage on zucchini quality, decreasing storage defects in persimmons and other important topics relating to crop science in the latest issue of the New Zealand Journal of Crop and Horticultural Science.

Source: Royal Society of New Zealand