As part of the GEREPHYTI project, the CRA-W stepped up its potato improvement programme between 2013 and 2017, helping to achieve potato genotypes that are more resistant to late blight by means of conventional selection and cisgenesis.
Conventional selection was introduced at the CRA-W in 2005, as a mean of creating improved genotypes. The selection model (see video http://www.cra.wallonie.be/fr/la-creation-de-nouvelles-varietes-de-pommes-de-terre-en-wallonie) was rendered more efficient. The choice of parents (or progenitors) is now based on assessing their level of resistance to late blight (caused by Phytophthora infestans): 127 varieties were tested under local pedo-climatic and epidemiological conditions during field trials at the Libramont and Gembloux sites. Only resistant varieties will be used for future crossings. As far as the methodology is concerned, GEREPHYTI has enabled acquisition of two rapid selection techniques that can be incorporated into the selection model. These are the detached leaf test, a protocol for testing susceptibility to mildew in the laboratory, and molecular marker-assisted selection, for early detection of the presence of resistance genes.
The second method used for creating improved material is cisgenesis. This is the process of transferring genes of interest between closely related plants, which could be crossed using conventional hybridization methods. Cisgenic varieties were obtained by selecting and isolating resistance genes in wild Solanum species (S. bulbocastanum and S. pinnatisectum). Techniques for the transfer of genes into the genome of varieties that are susceptible, but have other favourable qualities, were studied. This resulted in the production of more than 15 cisgenic clones of 3 varieties (Lady Rosetta, Charlotte and Louisa), which were consistent with the original variety and had increased resistance to late blight. Having acquired this new expertise, the CRA-W remains competitive in the field of new varietal improvement technologies, although cisgenesis is still covered by the same regulations as transgenesis.
Louisa, a new variety in the catalogue
Meanwhile, the project has led to enhanced collaboration with the potato sector: farmers now have the option of testing clones in their own growing conditions. 5 clones are currently being investigated on 4 farms. Finally, a registration application, introduced in the national catalogue of varieties in 2014, has been successful: Louisa, a variety intended for the industrial production of crisps, with good resistance to late blight, is now included in the Belgian catalogue.
GEREPHYTI has successfully combined innovative research, a source of new expertise at the CRA-W, and support for agriculture in Wallonia, particularly in the potato sector.
Project subsidised by Moerman funding.