Walnut Varieties - Notes From Ian Sheerin

(You can see images of walnut varieties on the Home & Public Info page of this web site. These articles come from our June 2019 and Autumn 2020 newsletters) 

Recollections About Our Cultivars

by Ian Sheerin

 

Taste Panel

About 25 years ago, a tasting panel was organized by food technology staff at Lincoln University with the aim of determining people’s taste preferences for selected NZ walnutcultivars. These cultivars had been previously selected and were being trialled as the most promising NZ selections for a commercial walnut industry. Rex and Meyric were included with others such as 151, 150, Stan, Franquette, NZ Purple, Dublin’s Glory etc.

The taste panel was held on one evening when about 40-50 people were invited to participate in a “blind” tasting. The evening was well organized. People were grouped into groups of 6 or so and we all sat around tables tasting previously shelled walnuts, which were identified by code numbers (not names) so you couldn’t really tell which varieties were which. We were all asked to rate the different cultivars on different criteria such as taste, colour, appearance, any aftertaste etc. Likert scales were used which is a scientific way in which people can score the cultivars against each criteria. These scores could then be used to rank the nuts, in a way that reflected a cross-section of people who participated in the tasting. The scoring was done by each participant independently so that in theory they would not be biased by what someone else might say. My recollection was that Stan came out as the most preferred nut (it was known as BLE300 back then). Rex, Meyric and NZ Purple all rated quite well on taste. On reflection, we thought that people may have rated Stan highly because of its appearance (as well as taste) ie it is bigger, has a nice shape and a light colour.

Was this tasting panel the reason for so much planting of Rex and Meyric?
The answer is “No”. Other research was being carried out by David McNeill who at that time was at Lincoln University. David trialled selected cultivars and compared them on various criteria including yield, shell seal, crack-out %, nut size etc. Rex, Meyric and NZ Purple were identified as being among the most promising. The Cracker of a Nut company subsequently found that most of the early volume came from plantings of Rex ie it came into fruiting earlier than other cultivars. That seemed the main reason that people planted Rex. Since then we’ve found that Stan is less productive than Rex (although the nuts are better). Also, Dublin’s Glory is susceptible to blight. We’ve also learned that Rex is prone to late frosts although most seasons it still produces good crops.

Ian Sheerin May 2019.

 

How do various walnut cultivars perform in Canterbury?

By Ian Sheerin. Autumn 2020

I’ve been planting walnut trees since about 1989. We’ve been on our current orchard near Prebbleton for almost 30 years and Nelson Hubber recently asked me to write an article describing how different cultivars have performed over time. I planted a number of different cultivars and people have asked over the years  – why did you do that? The reason was that back in 1990 nobody knew which cultivars would perform best in New Zealand, although a number of them had been selected as potentials for orchard plantings. It wasn’t until about the mid 1990s until David McNeill published his research that sufficient knowledge existed to guide the industry toward the current preferred varieties, particularly Rex and Meyric. (David was at that time working at Lincoln University).I’ve had the opportunity of observing how a number of cultivars have performed over about a 28 year period and this article is written from the viewpoint of a hands-on orchardist, though I hasten to add that we were busy with full time jobs and family as well. So here are some observations.

Rex
This was one of the first I planted and most people will know that it bears good crops most years, although it is prone to late frosts particularly around Labour Weekend (mid to late October). In Canterbury you should expect a late frost at least once every 4 – 5 years. How much snow is still on the mountains is a good guide to estimate your risk of late frost at that time of the year. If you’re closer to the mountains your risk will be higher. Rex is resistant to blight which is a good reason to plant this variety. It is a good processing nut, but not a very good in-shell nut. I definitely recommend other nuts for the in-shell market (see below). Rex establishes well and starts to come into production from about year 6, although with low volumes at first.

Meyric
Meyric has proved to be the best all round walnut for Canterbury. It takes a bit longer than Rex to come into production – about 8 years. It is a bigger tree than Rex. The nuts are very good in-shell nuts and they are easy to crack and produce beautiful halves. (Some types of walnuts don’t crack easily into halves). It is more prone to blight than Rex but it is also less prone to late frost and has been a more reliable producer in seasons with late frost problems. If you give consumers a choice between Rex and Meyric, the ones with previous experience of Meyric will choose it in preference every time. Meyric also produces bigger nuts than Rex and this helps with consumer appeal for the in-shell market. The NZ in-shell walnut market needs a lot more promotion and market development so it would be wise to take note of consumer preferences.

Dublins Glory
This was a cultivar that showed early promise but time has proven that is prone to blight, so your losses to blight outweigh any good quality nuts from this variety. The other problem is that it is the earliest cultivar to flower and leaf up so it is the most prone to late frosts. So in short, the industry should not encourage any plantings of Dublin’s Glory because of problems with blight and late frosts.

149
This cultivar was selected as number one in some of the evaluation work undertaken in the 1990s. (That rating was based solely on the characteristics of the nut). I only planted a few trees and found that they established well but only produce a disappointing number of nuts each year ie far less than most other cultivars. So again, the industry should not encourage any plantings of 149.

150
This is proving to be one of the best cultivars with good quality nuts and a good cropping history. It is a bit slower to start producing compared with Rex, but once established the quality of the nuts is very good. John Hanning who owned an orchard in Halswell found out from 150 that boron deficiency is an important consideration for Canterbury soils. Boron deficiency produces a particular deformity in the nuts but is easily cured by timely application of the recommended amount of boron fertiliser. Some of the compound fertilisers such as Nitrophoska or Yarra HydroComplex have boron in the trace elements. Anyway, I recommend checking your boron levels by soil analysis. 150 would be a good choice of cultivar for people wanting to diversify their risk. I wish I had planted more of them.

Franquette
Franquette is one of the top varieties in France and produces the best quality table nuts. The trees establish well but take a bit longer to start producing walnuts – in about year 10.  But they are a bigger tree and produce a lot of nuts. They are also resistant to late frosts as they flower later than most cultivars. I highly recommend Franquette, particularly for the in-shell table nut market. They are a good choice for Canterbury and would probably suit Otago also – even with the late frost issues there. The pollinator for Franquette is Spurgion.

G120.
These establish very well and start cropping quite early on – a bit like Rex does. The shells are bigger, as are the kernels. They are a very good nut, but they do have an amber colour – ie slightly darker than some cultivars. This does not seem a problem for consumers who tend to like the size of the nut – much bigger and more impressive than Rex. G120 taught me about the importance of micro-nutrients – things like boron, zinc, molybdenum. If you find the shells of the nuts are not fully developed, it is most likely because of micro-nutrient deficiencies which can be corrected by application of the right fertilisers. In summary, G120 is a good cultivar to think about, the main issue probably being that it has an amber colour to the kernel. 

NZ Purple
These established very well on our orchard and I think it was because we had the right mix of good shelter and soils. Some people have complained that NZ Purple did not establish well on their place and this seems to be due to insufficient shelter. So if you pay attention to having good shelter, NZ Purple is a good option. In some countries, the red or purple nuts have been part of a resurgence of consumer interest in walnuts so the NZ industry could take advantage of that opportunity also. The nut has a beautiful purple colour and appearance and tastes as good as any walnut. Some Asian customers say they taste sweeter and ask for them in preference to other varieties. In summary, I would recommend NZ Purple as being a major future market opportunity, but make sure you have adequate shelter from wind before you plant them.

Stan
Previously known as BLE300, Stan has very good quality nuts, but I have found that the crop volumes are a bit disappointing some years. From the perspective of consumer appeal, it rates very well – I recollect being on a blind tasting panel once, where everybody rated Stan as the best all round nut taking account of taste, colour and appearance. It has a nice light colour, which people seemed to appreciate. But I would tend to recommend other cultivars in preference mainly because some others have a more consistent cropping performance. 

Esterhazy
Esterhazy was slow to establish but produces these big beautiful table nuts. On our orchard they seem to be doing well now but were slow to establish and start producing. They might do better in warmer climates eg Banks Peninsula, Marlborough or Wairarapa. They are one of our favourite table nuts now, but I would recommend that they should be trialled in warmer climates to see if they establish better there.

Summary
From the above experience of different cultivars over the years, my top selections from these cultivars would be Rex and 150 for processing nuts. For in-shell table nuts, my top selections would be Meyric, Franquette and NZ Purple. I would recommend that the NZ walnut industry should pay attention to the different walnut markets and for the in-shell market, it should offer to consumers cultivars which are more suited to the in-shell walnut market.  

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New Zealand Walnut Industry Group