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Clubroot Brussels Sprout

TopRes® clubroot resistance in Brussels sprout

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 Brussels sprouts parental lines for use in producing clubroot resistant commercial hybrid varieties. The commercial varieties containing this trait provide higher yield under disease pressure.

Varieties

Commercial varieties: Cronus, Crispus, Cryptus


Patent

See the patent status by clicking here.

Please note that Syngenta is not responsible for the accuracy of the European Patent Office database. Please contact your patent expert for further information.

Financial Terms

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.


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