Saturday, March 30, 2024

Climate might move kiwifruit south

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The kiwifruit industry is pinning its faith on resilience and research to counter the possibility growing Green kiwifruit in Bay of Plenty might be impossible by 2100.
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NIWA scientist Dr Andrew Tait and primary sector consultant Alistair Mowat have put a specific local spin on the impact of climate change on regions’ ability to grow fruit crops, particularly those in warmer, temperate regions.

Tait said kiwifruit production around the key Te Puke district, which accounted for almost half of Green fruit, would steadily decrease over coming decades.

Estimates were it would be marginal by 2050 and most likely not viable by 2100 under all but the most stringent of global greenhouse gas emission options.

A key reason for the decline was expected to be the loss of winter chilling before bud burst.

The temperature drop from May to July usually resulted in more flowers and an earlier flowering period.

Tait said the use of the chemical hydrogen cyanamide, known as Hi-Cane, was common for helping promote bud burst and to counter warmer winters but it was not known how long that would continue to be allowable.

The use of the chemical did court a level of local controversy when applied in late winter but there had been no evidence to suggest it had health consequences.

The spray had been part of a raft of management practices used to significantly increase Green orchard productivity in recent years.

Tait said work looking at the implications of climate change on crop yields was not new and early work had included studies on its effects upon pipfruit.

“This was very much an empirical model we used and is a model type that could be used for other fruit types.”

Calling on NIWA temperature data and high resolution mapping, the researchers determined inland parts of Bay of Plenty or even districts in Otago and Canterbury might prove suitable for future plantings.

“But we do not think the Bay of Plenty is done. It is a well-established industry there and that has to be deeply considered.”

 However, there was also a high level of certainty that change would have to come.

“What proved interesting was that it virtually did not matter what greenhouse gas pathway was taken, with the exception of the most extreme and complete reduction in carbon through means we don’t have yet, all pathways resulted in a very similar type scenario.”

He suspected that initially over the coming decade growers would start to notice a gradual decline in Green yields.

“There is a big role for industry to play here.

“As an individual grower you are heavily invested and it is difficult to change your crop or your region. But as an industry such signals are important to lead those changes.”

The kiwifruit industry had proved adept at handling more immediate crises in the past.

The 2010 Psa outbreak resulted in a wholesale removal of the Hort 16a Gold fruit in response to the crisis, replacing it with today’s highly successful SunGold variety.

“So it is an industry that is quite vertically integrated and capable of adapting.”

Zespri innovation general manager Carol Ward said the study highlighted how important it was for Zespri and the New Zealand kiwifruit industry to think longer term on the potential impact of climate change.

“We are a resilient industry, thanks to several factors.

“One is diversity – many orchardists grow more than one variety of kiwifruit.

“Another factor is that we are continuously working to develop and evaluate new cultivars of kiwifruit through the world’s largest kiwifruit breeding programme with Plant and Food Research.”

She said that gave the sector the potential to develop new cultivars with different attributes, including resilience to environmental risks and productivity under different growing conditions.

“It is a very long-term programme and one that is vital for being prepared for future change.”

The industry was also innovating through different growing systems and solutions, including growing under shelter netting to protect against different climate risks in terms of short-term, seasonal factors and longer-term trends.

Kiwifruit Growers vice-chairman Mark Mayston said the organisation would continue to advocate for growers through its ongoing work with industry stakeholders including Zespri and Plant and Food Research.

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