Somatic hybrids and some progenies were distributed as in vitro plants to all partners, making possible the comparison of resistance of these materials in the different locations. There were similarities in the level of resistance of these genotypes with respect to the wild species involved. Most resistant materials from somatic hybrids had S.bulbocastanum as an ancestor, followed by S.circaeifolium, and, occasionally, S.okadae, whilst materials with S.commersonii and S.berthaultii were resistant in only some locations. In addition, materials with the accession of S. chiquidenum used for somatic hybridization showed a very high level of resistance. Of the wild species utilized for sexual hybridization, S.hondelmannii, S.jamesii, S.polyadenium, S.avilesii, and S.canasense gave the highest number of resistant progenies. Although these evaluations are preliminary and further field-testing is needed, the tendency is clear.

During the project and the planning meetings, discussions and the exchange of experiences, methods and materials were ongoing. Important topics were the different evaluation methods, the identification of the type of resistance, and strategies to manage the resistance in the field for sustainability.

The impact of this project has resulted in widening the genetic background of breeding materials for the Latin American, as well as the European partners, creating a base for further cooperation and exchange of materials in the effort to produce potatoes with more sustainable resistance to Phytophthora infestans in the future.

Submitted by L. Schilde; Email: lieselotte.schilde(at)uni-tuebingen.de

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[1] European Union Program for International Cooperation (INCO), Contract number: IC18-CT-98-0320

 The INCO (International Scientific Cooperation) Project Exploitation of the genetic biodiversity of wild relatives for breeding potatoes with sustainable resistance to late blight (Phytophthora infestans)[1] , November 1, 1998 to October 30, 2001, has generated some important outputs. Scientists from Europe (Germany and Spain) and Latin America (Bolivia, Colombia, Costa Rica and Ecuador took part. The six participating institutions and principal collaborators are found in Table 1. Lieselotte Schilde from the University of Tuebingen, Germany, coordinated the project.

Table 1. Institutions and principle collaborators in the INCO-PAPA Project.

A large number of wild species with valuable traits — especially resistance to Phytophthora infestans — were incorporated into breeding materials, thus strengthening the different breeding programs of the partners. The different species and the method of hybridization (sexual or somatic fusion) are found in Table 2. Somatic hybridization was used when crossing was difficult.