Last week at Macfrut, Star Fruits presented its new rootstock for growing kiwis: a possible small revolution for a sector that had not seen much innovation lately.
"Before getting to the heart of the matter, it is worth tracing the history of kiwi growing in Europe in order to understand why this new rootstock was developed. Until then, kiwis had never really been grown using rootstock, simply because there was no particular need for it. Kiwis were planted as free-standing plants, and this worked very well. On the other hand, although kiwi growing has expanded very rapidly in New Zealand, it is still relatively new compared to other crops such as wine, apple, or stone fruit. But from the 2010s onwards, with the appearance of PSA in particular, followed a few years later by Moria, the situation changed. In Europe, we have seen the emergence of mortality concerns in orchards, threatening the survival of crops. This year, Greece has even overtaken Italy in terms of volumes, and France is increasingly affected by the problem. Although we still find it difficult to clearly identify the causes of Moria (KVDS), we do know that the mortality rate is higher on waterlogged, compacted, clayey soil with a hydromorphic tendency," explains Guillaume Jarret, business developer at Star Fruits.
A rootstock hybridized in rice paddy conditions, with excellent performance in wet soil
The Actinidia valvata rootstock has been created to combat these problems of orchard mortality and provide a solution for a sector that is currently in danger. "The idea is to have a rootstock with a powerful root system that is resistant to waterlogged soils. This new rootstock has been named Jackson, in reference to its root system, which is reminiscent of the hairstyle of the iconic Jackson 5. It is hybridized in rice paddy conditions, so it performs extremely well in wet soils. We therefore expect it to have a high level of tolerance to PSA, and initial results seem to indicate signs of tolerance to KVDS (mortality) and salinity. In terms of grafting, it appears to be compatible with both Actinidia deliciosa and Chinensis.
At the European level, the French in vitro laboratory Eurostem (Star Group/Lafond) is responsible for propagating the rootstocks. They are now available from French and Italian nurseries: Vendries (France), Dalpane vivai (Italy), Righi Vivai (Italy), Dalmonte vivai (Italy), Marco Ribba vivai (Italy), Simeoni vivai (Italy) & Magalotti vivai (Italy) and Salvi vivai (Italy).
Nick Steyn, business manager (KiwiKo), Camille Herouard, technical and sector development manager (Star Fruits), and Andrea Righi, Italian nurseryman.
The objective is to test, measure, and learn
While this rootstock is a source of great hope for the sector, caution is the order of the day. For the time being, Jackson is only being offered to growers for experimental purposes. "Large-scale trials are currently underway throughout Europe to test the rootstock's resistance under real conditions, and its compatibility with commercial varieties.
We are well aware of the urgency of the situation, with strong demand from the sector, which is facing mortality problems. However, we are proceeding cautiously and seeking to gather as much information as possible about the rootstock's behavior. Each trial grower will receive several questionnaires to collect key data (on soil type, irrigation method, and disease prevalence) for analysis. As an international publisher and European KiwiKo licensee, we do not want to rush things. We would like to evaluate our rootstock in as many different conditions as possible, especially in problem plots. We are dynamic and have produced a lot, but we want growers to give it a reasonable try. That is why we are limiting sales to a maximum of 1,000 rootstocks per grower. We believe that this is a promising development for the sector, but we still need to prove that it can be planted on a large scale on a farm."
Equivalent affinity between yellow and green kiwis
Another advantage of this Jackson rootstock lies in its equivalent compatibility with yellow and green kiwis. "There are very few kiwi rootstocks on the market at the moment. There is the Bounty rootstock that has been available for a few years now, but it seems to give better results on yellow rather than green kiwis. With the Jackson rootstock, we can already see that the affinity is just as good on both. Once again, we are in the early days of kiwi rootstocks, so we are in the process of experimenting, which we want to do with humility. We therefore encourage growers to plant Jackson rootstocks alongside other rootstocks such as Bounty or Ro.Ki so that we can compare them in similar environments."
"Star Fruits is the European master licensee for KiwiKo, which has invested in one of the world's leading kiwi breeding programs: Yanoon BioTech."
For more information:
Camille Herouard
Star Fruits
[email protected]
Guillaume Jarret
Star Fruits
[email protected]