2004 Annual Report 4.What were the most significant accomplishments this past year? D. Progress Report: This report serves to document research conducted under a Specific Cooperative Agreement between the ARS and the Instituto Nacional de Tecnologia Agropecuaria. Additional details of research can be found in the report for the parent research project 3655-21000-037-00D, Allium, Cucumis, and Daucus Germplasm Enhancement, Genetics, and Biochemistry. For germplasm collection of D. pusillus, the following was accomplished. Based on national and international references and dried herbarium specimens from Argentine descriptions, collections were carried out in Mendoza and Central Buenos Aires provinces. The herbarium data refered to 20 collection sites within the Mendoza province. D. pusillus was recorded in the West of the province at 1,400 m.a.s.l., growing in very poor and not structured soils, with good water percolation. In herbarium specimens leaf, umbel and seed characters were measured and studied, in order to determine variability in previous collections. In the Mendoza province, plant and seed collections in our project were made at "Tupungato" during August and December 2003. Soils analysis and a description of the vegetation that grows together with D. pusillus were recorded. Plants and seeds were collected. At "Reserva Divisadero Largo" in January 2004, plants were collected and also soil samples were taken. At "Villavicencio" in May 2004 were collected several plants and the population was identified. At "Agua del Toro" (San Rafael) in July 2004 were collected several plants and the population identified. In Central Buenos Aires province, an area called "flooding pampas" was explored in January and February 2004. For this area, both D. pusillus and Daucus montevidensis had been cited as growing in plant communities known as flechillares. In a 2,000 km round trip, 22 sites with large populations were recognized and fruiting inflorescences were collected in 15 of them (a minimum distance of 20 km between sites). Although the morphological type that corresponded to the collections had been classified as D. pusillus by various authors, the close resemblance of both leaves and fruiting umbels to those of cultivated carrot was an indication that the populations belong to wild D. carota. Data on soil type, climate and accompanying vegetation at each site was recorded. The chromosome number of every collection was determined by root tip counts; it turned out to be 2n=2x=18. Chromosome counts were also performed in specimens from Mendoza, resulting in two different chromosome numbers 2n=2x=20 and 2n=2x=22, which is quite interesting. For morphological and genetic studies, an experimental plot has been established in the field, in Balcarce and also at Mendoza, with 15-20 plants of each of the 15 collections (likely wild D. carota), one cultivar, one wild D. carota introduction provided by P.W. Simon (USDA) and one introduction from Mendoza (likely D. pusillus). For study of the genetics of flowering habit in cultivated carrots, 15 hybrid combinations between "Criolla" (annual) and male sterile lines (biennial) were attempted. Seeds were obtained from 8 of these combinations. The F1 will be selfed during the 2004-2005 season. For Solanum germplasm collection, a field collection to the South of Mendoza and North of Neuquén was carried out in March 2004. Unfortunally few specimens of S. kurtzianum were collected, probably due to a very dry summer season. However, several introductions from S. kurtzianum and S. ruiz-lealli from Mendoza, collected in 2002 and 2003, will be evaluated for agronomic and tuber quality. The S. okadae collections in the Balcarce Potato Germplasm Bank had not been previously evaluated genetically or for breeding purposes.