The ECOPAPA (Enrichment of Potato Breeding Programs in Latin America and Europe with resistance to late blight, Phytophthora infestans) Project (supported by the European Union Program for International Cooperation with Developing Countries [INCO-DC] Contract ERBIC18 CT98 0318), November 1998 to February 2003, has been successful in meeting its objectives of broadening the genetic base of late blight resistance in the breeding programs in the participating countries in Latin America and Europe, as well as the transfer of knowledge and technology for marker-assisted breeding. The partners are INIA (Instituto Nacional de Investigación Agropecuaria) Uruguay; INRA (Institut National de la Recherche Agronomique) France; INTA (Instituto Nacional de Technología Agropecuaria) Argentina; PRI (Plant Research International) the Netherlands, which also has a coordinating role; PROINPA ( Foundation for the Promotion and Research of Andean Products) Bolivia; and SCRI (Scottish Crop Research Institute) United Kingdom.

Parental genotypes, 2x and 4x, with potentially useful late blight resistance genes, six from each institution, were sent to SCRI (United Kingdom) and quarantined. Thirty-four of them were subsequently distributed as an “exchanged set” by SCRI to each partner. The performance in field-testing of this exchanged set across all participating countries was evaluated for two cropping seasons, including the reaction towards the local late blight isolates. Some clones were identified as particularly suited for resistance breeding for specific regions, or (in a few cases) anywhere. The results of this multi-site foliage resistance study of these thirty-four genotypes will be published. PRI (the Netherlands), who was responsible for collating and analyzing the data, will prepare the draft manuscript.

To produce potential new parental lines with no specific local adaptation for exchange between the partners, INTA (Argentina) produced 91 families from tetraploid crosses between local varieties and the CIP (International Potato Center) “population B”, both with partial resistance. Tubers of these families were obtained during the third year and testing was in progress at the end of the project.

INRA (France) crossed 33 of the exchanged genotypes with five modern cultivars that were chosen for favorable traits like tuber aspect, yielding ability and cooking quality. Fifty-seven of the crosses yielded 200 or more seeds for each partner and 38 of them yielded 100–200 seeds each. At INIA (Uruguay) crosses were made among exchanged and other identified resistant genotypes. Many of these crosses combine blight resistance, a high level of virus resistance and commercial attributes. The selection of potential new cultivars by the partners is yet to be achieved. At SCRI breeders are evaluating materials generated by the program and have expressed interest in crosses with the Bolivian (PROINPA) clones.

To gain insight on the population structure of Phytophthora infestans in the different testing locations, one isolate of P. infestans was collected from each of the 34 exchanged clones after natural infection by four of the partners. In order to obtain pure isolates, sampling took place at a time when individual lesions were still small, from leaflets with only one lesion. These isolates were sent to SCRI and then re-distributed for analysis by SCRI, PRI and INRA. Isolates were not collected in Uruguay or Argentina. However, the Argentinean isolate used for artificial inoculation of the field tests was included. All isolates were characterized by SCRI for AFLP (Amplified Fragment Length Polymorphisms) fingerprints, metalaxyl resistance and mating type. A selection of the isolates was characterized by PRI for aggressiveness and by INRA for virulence. Furthermore, INRA evaluated oospore production of specific isolate combinations on different clones. SCRI will be responsible for drafting an article describing these characterizations. It should be published during 2004.

Scientists from INTA, PRI and SCRI used two diploid potato populations (a Solanum chacoense F1 mapping population from INTA and a S. tuberosum x S. phureja backcross mapping population from SCRI) with quantitative resistance to develop new molecular markers for foliage and tuber resistance. The S. chacoense population is being studied at INTA and PRI. At INTA a linkage map based largely on AFLP markers has been developed and markers for one QTL have been identified. PRI work has focused on the development of RGA (Resistance Gene Analogs) for this population. This is a relatively new kind of marker that targets sequences that are conserved in resistance genes and this work is ongoing. At SCRI, AFLP mapping of the S. tuberosum x S. phureja population is in progress. As an integral part of this endeavor, scientists from INIA, INRA, INTA and PROINPA were trained in molecular marker techniques.

Besides the two scientific papers mentioned in this article, it is expected that the QTL mapping of both the Solanum chacoense F1 mapping population and the S. tuberosum x S.phureja backcross mapping population will be published.

ECOPAPA held its initiation meeting at the GILB'99 Conference in Ecuador [GILB Newsletter No. 7, April 1999] and updates on the ECOPAPA project appeared in the GILB Newsletters No. 11, August 2000 and No. 17, October 2002.

Submitted by Roeland Voorrips, Coordinator ECOPAPA, Email: roeland.voorrips(at)wur.nl