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Jennifer Johnson-Cicalese, James J. Polashock, Josh A. Honig, Jennifer Vaiciunas, Daniel L. Ward, and Nicholi Vorsa

introgression and pyramiding in genetically productive backgrounds should provide future genetic gain for FRR and crop productivity. Literature Cited Bruederle, L.P. Hugan, M.S. Dignan, J.M. Vorsa, N. 1996 Genetic variation in natural populations of the large

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Neil O. Anderson, Peter D. Ascher, and Barbara E. Liedl

Since its evolution as an invasive species in Quebec (1930s), L. salicaria has spread across North American wetlands virtually unchecked. Initially, it was theorized that the rapid invasion was due to the absence of phytophagous insects (present in the native habitat). However, evolutionists theorized that invasive characteristics probably arose from introgressive hybridization with a native species (L. alatum), since their ecotypes overlap. Several horticultural cultivars are also fertile interspecific hybrids. These two species differ for diagnostic traits (number of flowers/axil, plant height, phyllotaxy, style morphology, seed dormancy). Minnesota L. salicaria populations were examined for evidence of introgression. Lythrum salicaria introgressive genotypes were found for all diagnostic traits. Seed dormancy was the most common, i.e., OP seed showed significant seed dormancy (F = 5.2, P = 0.024). Such hybrids would have adaptive advantages as weeds, having evolved for each ecotype by introgression with locally adapted L. alatum populations.

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Agnes RICROCH, Robert J. BAKER, and Ellen B. PEFFLEY

Biotin- and fluorescein-labeled probe has been used to map. specific sunflower rDNA sequences by in situ hybridization on mitotic chromosomes of Allium cepa, Allium fistulosum and interspecific hybrid derivatives, There are three hybridization sites in A. cepa and more than six in an interspecific triploid. This in situ hybridization technique offers new cytogenetic markers useful in the construction of a physical genomic map of Allium and offer a means to document introgression of these genomes.

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Paul W. Bosland and Jit B. Baral

In replicated trials at Las Cruces, N.M., the Scoville heat units (SHUs) of ‘Bhut Jolokia’, a chile pepper from Assam, India, reached one million SHUs. Morphologic characters revealed that ‘Bhut Jolokia’ is a Capsicum chinense Jacq. cultivar. Molecular analysis with randomly amplified polymorphic DNA markers confirmed the species identification and, interestingly, revealed that there may have been genetic introgression from Capsicum frutescens L. into ‘Bhut Jolokia’.

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Yuanfu Ji and John W. Scott

Resistance to begomoviruses tomato mottle virus (ToMoV) and tomato yellow leaf curl virus (TYLCV) has been introgressed to tomato (Lycopersicon esculentum) from L. chilense accessions LA 1932, LA 2779, and LA 1938. Resistance genes have been mapped to three regions on chromosome 6 using randomly amplified polymorphic DNA (RAPD) markers. We call these regions 1, 2, and 3. To facilitate breeding by marker assisted selection, advanced breeding lines with resistance from the above sources were assayed for the presence of RAPD markers to determine which were most tightly linked to begomovirus resistance. The best RAPD markers were then converted to sequence characterized amplified region (SCAR) markers or cleaved amplified polymorphic sequence (CAPS) markers. In addition, selected restriction fragment length polymorphism (RFLP) markers near the three regions were converted into CAPS markers, which were tested for association with the advanced breeding lines. Only LA 2779 derivatives have the L. chilense introgression in region 1, which is near the location of the Ty-1 gene and spans across CAPS markers 32.5Cla and TG118. Two region 1 RAPD markers UBC197 and UBC621 were converted co-dominant SCAR or CAPS markers, which were present in all 16 resistant breeding lines tested. Derivatives from all three accessions have introgressions in region 2. Further assays with more markers in this region are under way to determine the lengths and locations of the introgressions. No tightly linked RAPD markers have been found for the resistance gene from LA 1932 in region 3. RFLP and CAPS markers are being used to more precisely locate the region 3 gene.

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Min Wang and Irwin L. Goldman

Genetic relationships among 37 accessions of Beta vulgaris, including 21 table beet, 14 sugar beet, and two Swiss chard (Beta vulgaris ssp. cicla) accessions, were evaluated using randomly amplified polymorphic DNA (RAPD). Genetic distance was estimated based on the presence or absence of polymorphic RAPD bands. Multidimensional scaling plots of genetic distance values revealed that table beet inbred lines from the University of Wisconsin Table beet Breeding Program clustered in an intermediate position between sugar beet breeding lines and standard table beet germplasm, likely because of their origin from an introgression program designed to incorporate sugar beet genes.

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Peter J. Mes* and James R. Myers

Tomato lines carrying the genes Aft, atv, Abg, hp-1, and an as yet undetermined gene from the introgression line LA2099 have been combined to produce fruit with elevated anthocyanin content. The antioxidant activity of juice made from anthocyanin-expressing tomatoes was compared to juices made from tomatoes with varied carotenoid content. The contribution of anthocyanin to the total antioxidant activity of the whole fruit in current material is small, but with potential for significant improvement. The increase in flavonoids in the elevated anthocyanin lines has increased water-soluble antioxidant activity of the fruit in vitro.

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Angela Baldo, Larry Robertson, and Joanne Labate

Cultivated tomato varieties are genetically extremely similar. We identified 764 Unigenes with potential single nucleotide polymorphisms (SNPs) among more than 15 cultivars from public expressed tomato data. By sequencing regions from 53 of these Unigenes in two to three cultivars, we discovered an unexpected wealth of nucleotide polymorphism (62 SNPs and 12 indels in 21 Unigenes). This included a high proportion of predicted nonsynonymous nucleotide (17 of 33 SNPs in exons) and nonconservative amino acid (6 of 16 nonsynonymous SNPs) changes. We hypothesize that five of these regions are associated with introgressions from wild relatives. Identifying polymorphic, expressed genes in the tomato genome will be useful for both tomato improvement and germplasm conservation.

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Dale E. Kester and Thomas M. Gradziel

Approximately twenty native almond species have been described. Representative germplasm from seven of these are present in UC collections and have been used in crossing. Three specific breeding lines utilizing these species are described. One (1980 series) involved increasing yield potential through selection of high blossom density following gene introgression from Prunus fenzliana. A second involved incorporation of self-fertility, late bloom, smaller tree size, early maturity, high blossom density, and desirable nut characters from Prunus webbii into commercial breeding lines. A self-fertile selection resembling `Nonpareil' has been obtained from this material. The third line involves transmission of a unique thin, netted-surfaced, hard-shell phenotype from Prunus argentea.

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W. Patrick Wechter, Ralph A. Dean, and Claude E. Thomas

Two 24-mer primers, MUSKFOM I and MUSKFOM II, were developed that amplify a 1.5-kb DNA fragment in race 1 Fusarium wilt resistant muskmelon (Cucumis melo L.), but not in race 1 susceptible germplasm tested. Three race 1 resistant cultivars and two race 1 resistant breeding lines as well as eight race 1 susceptible lines were analyzed using the two sequence-specific primers in the polymerase chain reaction. These primers should prove valuable for nondestructive determination of Fom 2 gene introgression in breeding programs.