Controlled environment trials to reduce Psa-V risk to the early maturing gold kiwifruit Y356 are showing very promising results, say Simon Dickie, who owns the plant protection rights to the variety.

Investment rewarded
“We are working out how to get enough control over variations in climate. However, growing under cover presents some challenges such as what to do about rainfall and water. Pollination is another issue as we know bees do not work well under plastic. Also how does increasing the temperature affect maturity?”

The research is costly but Simon believes the investment will be rewarded. “Significant resources have been required and invested and we have got some really interesting information which is part of our IP.

“The outcomes could be significant because the diploid gold cultivar has a more appealing taste in certain markets than other gold varieties and those are high return markets,” he says.

Variety rights
Y356 is described as “a kiwifruit plant particularly distinguished by very early maturing fruit, hairless fruit surface with conspicuous mid-brown lenticels, yellow fruit flesh, ovoid longitudinal and circular cross section fruit shape, slightly blunt protruding stylar end”.

Simon, who has been growing kiwifruit since 1979, offered Y356 to Zespri but it was turned down. “It was not unexpected that Zespri would choose to look at alternative options out of Plant & Food, over which it would have exclusive plant variety rights.”

Plant & Food bred Zespri’s SunGold or G3 which has proved more tolerant of Psa-V and has virtually replaced Hort16A since the arrival of the disease, with growers cutting out the former gold and progressively re-grafting to the new variety.

Under current government regulations, kiwifruit grown in New Zealand can only be exported by Zespri, with the exception of fruit going to Australia.

Simon says a collaborative marketing arrangement for Top Gold with Zespri may be possible in future.

It wouldn’t be the first time the fruit has been exported this way. In a landmark collaborative marketing agreement in 2011, industry regulator Kiwifruit New Zealand gave approval for First Fresh NZ Ltd of Gisborne to launch a consumer trial of First Gold, in Thailand and Hong Kong supermarkets.