Micro-propagation of peonies has been talked about a lot, yet up until now it used to be a hit-and-miss story as there were many problems. In a meta-article about the subject in 2012, the following still to be solved issues were noted:(1)
(1) Explant contamination is serious. Bacterial and fungal contamination is rife in P. lactiflora initiation culture, particularly serious when underground buds are chosen as explants – understandably so. (2) Hyperhydricity and browning. In the area of browning, novel methods and mechanisms have yet to be obtained, although some valuable advances have recently been achieved. (3) Shoot differentiation is difficult. Herbaceous peony needs to be rapidly propagated by direct bud proliferation and not indirectly following callus differentiation. (4) The induction percentage of somatic embryos is low, and when these do form, deformity is high. (5) Rooting percentage remains low and the quality of roots is in general not high. Wang and his co-workers confirmed that rooting of tree peony was successfully achieved under various conditions such as 4 mg l−1 IBA, cool cathode fluorescent lamps, and photoautotrophic. Similar trials should be carried out on herbaceous peony which would greatly benefit the micropropagation of this difficult-to-root ornamental plant. (6) Transplanted plantlets survive poorly, primarily due to the low quality of roots, ineffective transplant period, unsuitable environmental conditions and seedling dormancy after rooting, all of which negatively impact the survival percentage of transplanted plantlets.
The intersectionals (Itohs) seem to be the easiest ones to propagate this way. A few laboratories are working on this and another one, IribovSBW from Holland, has just joined the band: in an article in Greenity, a trade journal, they claim to have solved the problems and are now able to propagate any cultivar from any group with hardly any losses. It appears those new fancy cultivars that are so vastly expensive for such a long time will only remain so for a short term in the future.
So, for those interested, here’s my translation of the article about the breakthrough:
Large-scale fast and clean propagation of peonies.(2)
The popularity of peonies is still rising. The acreage devoted to it is increasing fast. But when it comes to propagation, the grower has only one option, dividing the roots of mature plants. IribovSBW succeeded in adding another choice for growers. Large-scale propagation from tissue-culture is now possible.
Initially flowerbulbs were the main activity in the company of Eloy Boon and his partner Evelien Huis, therefore it was named Iribov when it was founded in 1992. Iribov comes from Irises from Bovenkarspel, the location where Boon grew up. Irises where followed by lily and nerine. Evelien Huis in ‘t Veld had already looked at peonies, but like tulips, they could be classified as difficult crops. Besides, at that time peony didn’t belong to the crops that were grown large-scale.
“At a certain point in time we did succeed in propagating them through tissue-culture, but the propagating rate was very low. Eventually we didn’t pay much attention to it anymore as there were enough other crops to work with,” says Eloy Boon, CEO of IribovSBW in Heerhugowaard.
Stil the peony kept intriguing, according to Evelien Huis in ‘t Veld. “Several times I started working with it again. It remained a difficult crop. The biggest problem with peonies was that there are three phases that have to succeed all: the creation of the tissue-culture plants, the rooting, and the growth phase in the greenhouse. Many times one of the three phases did work fine, but all of them not.”
A new client arrived with peonies in 2012. “We did have enough experience with helleborus and anemone, both crops from the genus ranunculae, to which paeonia also belongs.”
As so often with propagation of crops through tissue-culture, looking at it is extremely important. “I’m mostly interested in how a plant grows in its natural habitat. What happens during the whole growth cyclus. By looking at that thoroughly you get insights that can be used in the laboratory. I want to understand how a plant works. And as it turns out it is not so much the medium, but other aspects. We succeeded in getting from 10% survival rate to 90%.”
What those aspects are, she cannot say, because for the most part that’s the secret of a successful fast propagation. There has been more than enough testing she says: “these last years we have propagated several dozens of cultivars from all groups of peonies through tissue-culture. They all came back true to name.”
By now there are many tissue-cultured peonies growing in the climate rooms and greenhouses of IribovSBW. “From now on, we can upscale and see what markets there are for this product,” Eloy Boon says. Expectations are high, he himself sees multiple possibilities: “With this a hybridizer who has a new cultivar can bring it to market faster. What’s also possible is that a grower of a popular cultivar chooses to renew his crop by this technique.” For him the advantages are clear. “By choosing for tissue-culture a grower starts with clean material. It is free from diseases and pests, like nematodes and viruses.”
The result offers another possibility: one-way traffic in the cultivation. Currently a grower propagates from motherplants which he divides. How healthy these motherplants are is not always well known. This way diseases and pests can go from the motherplant to the young plant. By choosing for cultivation from tissue-culture, the grower can start clean and deliver his plants after a few years.
Earlier this year IribovSBW, together with Hobaho and Dümmen Orange, reported their success in fast increasing tulips and now peony has been added. Are there other crops on the IribovSBW list that haven’t revealed their secrets as yet? Boon: “These last years we have run a program of difficult crops, of which we think there will be demand for. Next to tulip and peony the focus is on food crops, like cocoa, cashewnut and pepper. We’re working on the first two in Ghana, to give the locals the possibility to make better returns from these crops.”
Eloy Boon and Evelien Huis in ‘t Veld founded Iribov in 1992 in Enkhuizen. Initially the focus was on fast propagation of flowerbulbs through tissue-culture. Soon herbaceous plants, cutflowers and pot plants were added, later also vegetables and fruits. The company moved to Heerhugowaard, where there was more space, in 2007, to keep growing. In 2011 they took over the multinational SBW. IribovSBW has plants in Holland, Macedonia and Ghana. Yearly production of the company is 25 million plants of about 300 crops and 10,000 varieties. Next to ornamental crops the company is also active in food crops. The latter account for about 30% of turnover and this part is expected to increase. Some 370 people are employed by the company. Next to fast propagation the company also has a molecular laboratory for, amongst others, fast detection of pathogens and marker analysis for identification and breeding support.
- Miaomiao Shena, Qi Wang, XiaoNan Yu, Jaime A. Teixeira da Silva . “Micropropagation of herbaceous peony.” In: Scientia Horticulturae, 2012, no. 148, pp. 30-38.
- Dwarswaard, Arie. “Veel, schoon en snel pioen vermeerderen.” In: Greenity, no. 42, Oct 25th, 2018, pp. 42-43.