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NZ Walnut Site |
Cultivar Importation Project |
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Keep track of our new cultivars as they journey to NZ, undergo quarantine and begin growing in our orchards. Latest News:The trees have been grafted and are with the propagators. They will be released for planting in the winter. See them as they were in November after grafting, here... Earlier Stages:Great news! Graft wood from our 3 imported walnut cultivars has been released from quarantine, and is now in the hands of walnut propagators. The imported walnut trees entered the quarantine coolstore on 12 July, so the material would have received around 860 chilling hours by the time the graft wood was cut on 17 August. Graft wood was cut by Plant and Food Research quarantine staff, with the supervision of a MAF inspector. We received release documentation for the graft wood from ‘Lara’ and ‘Howard’ on 20 August. Release documentation for the ‘Tulare’ graft wood was delayed until 24 August while some final lab testing was carried out (the lab testing showed that some tiny signs of fungus on these trees were of a kind common in NZ). Plant and Food Research staff carefully packed the graft wood into polystyrene boxes with ice, and sent them by overnight courier to Darrell and Karen Johnston at River Terrace Nurseries (Brightwater, Nelson). The ‘Lara’ and ‘Howard’ graft wood arrived on 25 August, and the ‘Tulare’ graft wood a day later. Darrell estimated that there is sufficient ‘Lara’ material to graft 75 trees, with 53 grafts possible from the ‘Howard’ material, and 65 grafts from the ‘Tulare’. However he cautions that the success rate may not be high, since with the small amount of material, propagators will have to use everything available, rather than being able to choose just the best buds. Darrell couriered a parcel of graft wood from the 3 cultivars to David Murdoch at Peninsula Tree Nursery (Little River, Canterbury). The intention is that some of the grafted trees will be put into a new NZWIG cultivar trial to be planted out in winter 2011. Darrell and David will also plant some of the grafted trees at their own properties for the purposes of bulking up the new cultivars. NZWIG is keen to see grafted trees of the new cultivars available for sale to members as quickly as possible, and this bulking up should provide a supply of graft wood for future propagation. The original imported trees (just the roots and a short trunk remaining, after the graft wood was cut) are still in the Plant and Food Research quarantine coolstore and will stay there until we can confirm the success of our grafting in October. 16 July: The hardening-off process for our walnut trees is complete, and they were transferred from the quarantine glasshouse into the quarantine coolstore last week. 29 June 2010: Our trees are being hardened off in the quarantine glasshouse, ready for coolstore. Photos taken on 15 June by Plant & Food Research quarantine staff show that some trees had completely lost their leaves at that date, while others had partially lost their leaves. The trees will be placed in the quarantine coolstore as soon as the hardening off is complete. Check out the photos - here. The final application to release the budwood will be submitted to MAF in July. Assuming this is approved, in late July we will take budwood from the trees for grafting. Grafting will be done in August, with the aim for the new trees to be ready for planting the following winter. Of these grafted trees, the plan is for some to go into a new NZWIG cultivar trial, and others to go to propagators’ properties so the new cultivars can be bulked up and made available to members as quickly as possible. Heather North of the NZWIG research committee spoke about the cultivar import project at the recent AGM, outlining the import process, the current status of the trees, and the planned next steps. The update also showed that the project is on track as compared to the allocated financial budget. 20 April 2010: We have received the great news that the required tests for our trees in quarantine are now complete, with no disease problems found. The final tests were for Brennaria and Phytoplasmas, and we heard back in early April that these disease-causing organisms were not found on the trees. The next step was the final growing season inspection of the trees in quarantine, carried out by MAF last week. No issues arose from this inspection. The
staff at Plant & Food Research will now harden off the tested
trees
(two of each cultivar) in preparation for cool storage. Once
dormant, the trees will wait in the cool store from early May until we
are ready to take budwood off them for grafting in winter.
The
hardening-off process was first trialled on the 'spare' untested trees
(these ones will not be available for release) and it was successful
and caused no adverse effects, so we can have confidence it will also
be successful for the tested trees. Our walnut trees are continuing to grow extremely well in quarantine. The two trees of each cultivar which in December were headed back hard to promote budwood growth have responded well, and now have a good selection of 1-2m shoots. The other trees of each cultivar which were not headed (these are our ‘spares’ which are not being tested for release) grew to around 4m by late January (some reached the glasshouse ceiling), prompting Plant&Food Research to check whether we would mind these trees being topped! In early February some small black spots were found on the leaves and stems of several plants, and samples were sent to MAF for diagnostic analysis. The results showed several fungi but these were not of significant concern; however, a small amount of leaf tissue was removed from the trees and an eradicative spray was applied to eliminate any possible risk. The staff in quarantine are now planning the method for hardening-off the green shoots and budwood, and have discussed this method with Darrell Johnston. This hardening-off will take place in early April and will prepare the trees for dormancy in coolstore (where they will be kept until we are ready to take budwood from them in July, assuming our trees are cleared for release by MAF). The remainder of the required testing will also be done during March, covering the disease-causing organisms Brenneria rubrifaciens and walnut witches broom phytoplasma. 25 January:
A good start has been made to the series
of tests our trees will undergo to check them for various diseases of
concern to
NZ. In November, samples were taken and tested for Cherry
Leaf Roll Virus.
Results were sent to us just before Christmas with the good news that
no
disease was found. Monday 14 December: We have reached the point in the growing season when PFR and MAF are beginning to carry out the required tests for various diseases. First up is the test for Cherry Leaf Roll Virus – material was sent away last week for this test. Because NZWIG members voted for a budget to test and release only two trees of each cultivar (not all five), the arrival of this testing phase meant we had to select which two trees of each cultivar to test. If testing shows the selected trees to be disease-free then we will be able to take budwood off them at the end of the season for grafting in NZ. Also, because we can only take budwood off the two (tested) trees of each cultivar, it is important that we maximise growth of suitable budwood on these trees so that we can graft sufficient plants for a trial of the new cultivars in NZ. On the recommendation of Darrell Johnston, we therefore decided to cut back the current shoots to 5 buds on the trees to be tested and released (the other trees of each cultivar will not be cut except to prevent them hitting the ceiling of the glasshouse). This should encourage new shoot growth, which should be of suitable size by the end of the growing season. See photos of before and after cutting back ...here Monday 30 November October 2009 Check out the photos of the trees in quarantine on 27 October ... here. September 2009 Thursday
24 September The MAF Inspector visited on Tuesday 22nd. She was very pleased with the plants, and has agreed that the 6-month growing season inspection period can considered underway. See the latest photos. When Plant and Food Research quarantine staff inspected the walnut trees on arrival, they found signs of disease on three trees. These included a rot on an old pruning wound, vascular staining in a main tap root, and lesions on the roots. The MAF inspector, with agreement of the PFR Plant Pathologist, decided these three plants were unacceptable for importation into New Zealand. If the trees had been included within the consignment, they would have jeopardised the release of the whole importation. It would also be necessary to establish what the organisms were that were causing these symptoms. To achieve this with certainty would be very costly and would be our responsibility as the importer. The research committee has thought through the options and has made a decision (with the backing of the NZWIG committee) to go with the PFR/MAF recommendation to destroy the three trees. It is unfortunate to lose these trees (2 Howard and 1 Tulare) but we believe it is the safest option. It is unlikely to affect our plans, since in any case we will be choosing only the best 2-3 trees of each cultivar (we imported 5 of each cultivar) for testing and release. Monday 14 September: Palmerston North walnut propagator Vern Harrison visited our trees in quarantine today. He discussed with the quarantine staff the care of the trees in their planter bags, and maximising budwood growth. Nelson walnut propagator Darrell Johnston has also had phone discussions with the quarantine staff and may visit the trees during the growing season. The quarantine staff have excellent horticultural skills and knowledge but have not dealt specifically with walnuts before, so we are keen for the best walnut-specific advice to be available to them and are grateful that these expert propagators have been providing this. August 2009: August 21: Plant and Food Research (PFR) received the trees on Monday, has carefully inspected them and has potted them up. The trees were headed fairly hard by the propagator in Tasmania for ease of packing and transport, and this heading will also promote the scion wood growth we need during the coming growing season. Tuesday 18th August: Our 15 walnut trees arrived safely at the quarantine facility in Palmerston North late yesterday afternoon. They have been carefully inspected today and look to be in good health. Friday 14th August: Our consignment of walnut trees successfully received biosecurity clearance from MAF Biosecurity at Auckland Airport this afternoon, which is a great result. The packages of trees will now be held in the courier company's coolstore at the airport over the weekend, and then be sent on to the quarantine facility in Palmerston North on Monday. Prior to this we have had a few anxious days tracking the consignment's slow progress from Tasmania to Melbourne to Sydney and finally to Auckland - there have been a number of delays from the courier, meaning that the trees arrived in NZ today rather than on Wednesday as originally expected. However, there have been no delays at MAF Biosecurity, where the personnel have been very helpful. We arranged that the nursery in Tasmania would apply the insecticide and miticide treatments (required by our import permit) prior to packing, and this was witnessed by the Australian Quarantine inspector, so there were no further treatments required when the trees reached Auckland. Our bare-rooted walnut trees left Tasmania on Monday 10 August. On this day they were cleaned by the propagator in Tasmania, and inspected by the Australian Quarantine Service. They will be carefully packed and sealed in polystyrene boxes, with wet material around their roots. A courier will pick them up from the nursery, and then they will be air freighted to the NZ quarantine facility in Palmerston North, travelling via Sydney and Auckland. While in Auckland they will be inspected by Biosecurity NZ, and insecticide and miticide treatments will be applied to them. We are expecting them to arrive at the quarantine facility in Palmerston North on Thursday 13th or Friday 14th. July 2009: Thurs 2 July we received our permit from MAF to import the 3 new walnut cultivars. June 2009: Research sub-committee meets to make a final decision on the cultivars to be imported. The decision to import Lara, Howard and Tulare was supported by NZWIG. The decision was reported at the NZWIG AGM, with notes on the reasoning circulated. [Read the committee decision here] February 2007: Research sub-committee begins investigating methods, facilities and costs for importing and quarantining new walnut cultivars from overseas. May 2007: Research sub-committee, working with walnut propagators and other walnut experts, completes the writing of a section on Post-entry Care and Propagation for the new MAF testing manual for importing Juglans. June 2008: Research sub-committee draws together the information it has gathered in the past 16 months, and presents a case at the NZWIG Special General Meeting for importing new walnut cultivars from Tasmania. Members are interested in the idea but request further information, particularly on the taste and nut quality of the cultivars proposed for import. July 2008: The new testing manual for importing Juglans is completed by MAF and is available for use. September 2008: NZWIG imports samples of nuts from new walnut cultivars in Tasmania into the transitional facility at Lincoln University. A Cracker of a Nut provides samples from New Zealand cultivars, and Lincoln University carries out testing of nut taste and quality. NZWIG members are involved in the (blind) tasting panel. April 2009: NZWIG holds a Special Information Meeting on the cultivar import proposal, having posted out detailed briefing notes in advance. The briefing notes cover the further information gathered by the research sub-committee since the June 2008 SGM, and a summary report from the Lincoln University researchers on the results of the taste and quality testing. The researchers speak at the meeting and members ask detailed questions and contribute comments. [Read the briefing notes presented to the meeting here.] May 2009: NZWIG sends out a postal ballot to members (along with notes from the Special Information meeting) so all financial members can vote on the proposal to import 3 new cultivars from Tasmania. 56 members vote, of which 36 were in favour of proceeding with the project.
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