TopRes® clubroot resistance in cabbage
Clubroot is a widespread disease that causes serious problems in many brassica growing areas. The disease is caused by Plasmodiophora brassicae , a one-cellular organism. Symptoms of the disease include root malformations with hard swellings (clubs), that eventually rot. The disease also causes stunting through reduced growth, and wilting of leaves is observed under water stress.
Clubroot is considered to be the most important disease in brassica crops. This soil-borne disease is present in many growing areas, and can locally prevent brassica culturing. Chemical control of the disease is not effective. Therefore, good genetic resistance of the crop is important for its protection against the disease. For brassica crops the trait potential is significant as the disease is among the most important economic loss causing disease in brassica's.
The genus of the Brassicas comprises several species of commercial interest, such as B. rapa (Chinese cabbage, pak choi, turnip), B. napus (oil seed, swede), B. juncea (mustard), B. nigra (black mustard) and B. oleracea (cauliflower, broccoli, cabbage, Brussels sprouts, savoy cabbage, borecole, kohl rabi and others). While sub-species within a species of the Brassica genus are usually sexually compatible, this is not necessarily the case between different species of the Brassica genus. For example, B. rapa and B. oleracea do not have the same number of chromosomes (10 chromosomes versus 9 chromosomes) and are therefore not sexually compatible. This renders the transfer of a trait from one brassica species to another particularly difficult.
Several sources of resistance to clubroot have been described within the Brassica genus. Some resistances are monogenic, some polygenic, some are dominant, some recessive. Monogenic dominant resistances have been described in B. rapa and B. napus such as, for example, a monogenic dominant resistance in the B. rapa Chinese cabbage. Chinese cabbage F1-hybrids with this resistance have been shown to have good protection against clubroot, although a small number of strains (`races`) of clubroot have been able to break through this resistance. Such races seem more prevalent in Asia than in Europe.
By contrast, only polygenic, recessive sources of resistance have been described in the brassica species B. oleracea . Such sources have proven not only to be insufficiently resistant to clubroot, but they are also very difficult to transfer between commercial B. oleracea lines. This renders the breeding of the resistance a difficult and time consuming task.
Therefore, the resistance trait described here is unique in developing clubroot-resistant B. oleracea plants in which the resistance is also easy to breed and transfer to commercial B. oleracea lines, as it is a monogenic and dominant trait.
The trait can be introduced into cabbage parental lines for use in producing clubroot resistant commercial hybrid varieties. The commercial varieties containing this trait provide higher yield under disease pressure.
Commercial varieties: Tekila, Kilazol, Kilaton, Kilaxy, Kilajack, Kilaherb, Ramkila, Kilagreg, SG3443
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Based on FRAND license terms the licensee pays a fixed fee / ks for the use of this resistance locus in commercial varieties. This license includes the TopRes® trademark license.
You can review an example of a standard license agreement by clicking on the link: Standard License Agreement
Access to trait know-how and molecular markers to increase the efficiency with which the trait can be introduced into the market will be negotiated as a lump-sum or an additional royalty rate.
Materials and Know-How
To speak to us about how we can best support you in gaining access to this native trait via TraitAbility and how it can benefit your breeding programs please contact us for more detailed information. If you are a member of the International Licensing Platform you can obtain a basic patent license directly through that platform.
As Syngenta continuously produces new materials and increases its know-how on this native trait, we can offer a licensee additional know-how and material related to this native trait further to the patent license through TraitAbility.
In its continued breeding programs Syngenta has obtained broad experience with the application of this trait in various brassica crops. In addition to granting access to the patented trait, Syngenta can offer Cauliflower breeding lines which contain the resistance genes in a suitable genetic background and molecular markers to assist the breeding. This will save the licensee 4-5 years of back-crossing work in the process of commercialization.