Search Results

You are looking at 51 - 59 of 59 items for

  • Author or Editor: J.W. Scott x
  • Refine by Access: All x
Clear All Modify Search
Free access

Yuanfu Ji, Jay W. Scott, David J. Schuster, and Douglas P. Maxwell

Resistance to begomoviruses, including bipartite tomato mottle virus (ToMoV) and monopartite tomato yellow leaf curl virus (TYLCV), has been introgressed to cultivated tomato (Solanum lycopersicum) from Solanum chilense accessions LA1932 and LA2779. A major gene, Ty-3, responsible for resistance to ToMoV and TYLCV was previously mapped on the long arm of chromosome 6. In the present study, we identified a 14-cM S. chilense introgression on the long arm of chromosome 3 in some resistant breeding lines derived from LA1932. A new begomovirus resistance locus, Ty-4, was mapped to the 2.3-cM marker interval between C2_At4g17300 and C2_At5g60160 in the introgression. Analysis of a population segregating for Ty-3 and Ty-4 demonstrated that Ty-3 accounted for 59.6% of the variance, while Ty-4 only accounted for 15.7%, suggesting that Ty-4 confers a lesser effect on TYLCV resistance. Recombinant inbred lines (RILs) with Ty-3 and Ty-4 had the highest level of TYLCV resistance. The PCR-based markers tightly linked to the Ty-4 locus as well as the Ty-3 locus have been recently used in our breeding program for efficient selection of high-levels of begomovirus resistance and now allow for efficient breeding by marker-assisted selection.

Free access

J.W. Scott, S.A. Miller, R.E. Stall, J.B. Jones, G.C. Somodi, and V. Barbosa

Thirty-three tomato (Lycopersicon esculentum Mill.) or L. pimpinellifolium (L.) Mill. accessions were inoculated with race T2 of Xanthomonas campestris pv. vesicatoria (Xcv) in a field experiment at Wooster, Ohio, in Summer 1995. These included accessions selected for race T2 resistance in greenhouse tests in Florida, and accessions from Hawaii, Brazil, and Bulgaria. One L. esculentum (PI 114490-1-1) and three L. pimpinellifolium (PI 340905-S1, PI 128216-T2, and LA 442-1-BK) accessions had no Xcv symptoms. This is the first report of resistance to Xcv race T2. Partial resistance was found in PI 271385, PI 79532-S1, PI 155372-S1, PI 195002, and PI 126428. Most of the 33 genotypes were tested for race T1 resistance in Presidente Prudente, Sao Paulo, Brazil in summer 1993. Hawaii 7983, PI 155372-S1, PI 114490, PI 114490-S1, and PI 262173 had greater resistance to T1 than the susceptible control `Solar Set'. Comparisons with earlier experiments in which accessions were inoculated with race T1 or T3 indicated that the most consistent source of resistance to all three races was PI 114490 or selections from it.

Full access

David W. Burger, J.B. Katcher, Nathan E. Lange, Jose L. Saenz, Scott P. Sherman, and Mark R. Stoutemyer

Graduate students in horticulture at the Univ. of California, Davis, spent an academic quarter learning how to use the Internet and World-Wide Web (WWW) to access and collect information. The collected information was organized and placed on the WWW where it is available to anyone with access to the Internet.

Free access

J.W. Scott, S.A. Miller, R.E. Stall, J.B. Jones, G.C. Somodi, V. Barbosa, D.L. Francis, and F. Sahin

Thirty-two tomato (Lycopersicon esculentum Mill.) or L. pimpinellifolium (L.) Mill. accessions were inoculated with race T2 of Xanthomonas campestris pv. vesicatoria (Xcv) in a field experiment at Wooster, Ohio, in 1995. Plants from accessions which segregated for race T2 resistance in greenhouse tests were selected and these are designated by hyphenated extensions below. The eight most resistant accessions from 1995 and PI 262173 were retested in 1996. Lycopersicon esculentum accession PI 114490-1-1 had virtually no Xcv symptoms either year. Lycopersicon pimpinellifolium accessions LA 442-1-Bk and PI 128216-T2 expressed a high level of resistance in 1995, but only partial resistance in 1996. Accessions with partial resistance for both seasons were PI 79532-S1, PI 155372-S1, PI 126428, PI 271385, PI 195002, PI 262173, Hawaii 7998, and Hawaii 7983. PI 79532-S1 is a L. pimpinellifolium accession and the remaining seven are L. esculentum. Twenty accessions tested in 1995 for T2 plus 10 other accessions were also tested for race T1 resistance in Presidente Prudente, Sao Paulo, Brazil, in 1993. Hawaii 7983, PI 155372-S1, PI 114490, PI 114490-S1, and PI 262173 had greater resistance to T1 than the susceptible control, `Solar Set'. Comparisons with earlier experiments, in which accessions were inoculated with race T1 or T3, indicated that the most consistent source of resistance to all three races was PI 114490 or selections derived from it.

Open access

Peter J. Stoffella, Herbert H. Bryan, Teresa K. Howe, Jay W. Scott, Salvadore J. Locascio, and Stephen M. Olson

Abstract

Ten fresh market tomato (Lycopersicon esculentum Mill.) genotypes were evaluated for yield stability in 7 environments within Florida. Genotype × environment interaction was significant for yield of marketable fruit. Linear relationships between mean yields of individual genotypes and environmental mean yields were evaluated to determine genotype stability. Mean square deviations from linear regression (s2d), regression coefficients (b1) and coefficient of linear determination (R 2) were used to evaluate phenotypic stability. ‘Sunny’, Castlehy 1035’, ‘Burgis’, ‘FTE 12’, and ‘Duke’ were considered stable and high yielding. An advanced breeding line, 827015-IBK, was considered stable but low yielding. ‘Hayslip’, D76127, ‘Flora-Dade’, and ‘Walter PF’ were considered unstable. This study suggests that yield stability differences occur among fresh market tomato genotypes. Therefore, selection of tomato genotypes for improved adaptability should be considered in tomato breeding programs.

Free access

John W. Scott, Elizabeth A. Baldwin, Harry J. Klee, Jeffrey K. Brecht, Stephen M. Olson, Jerry A. Bartz, and Charles A. Sims

‘Fla. 8153’ is a fresh-market tomato (Solanum lycopersicum L.) hybrid that is being released for the premium tomato market. It has high lycopene content and an attractive, deep red interior color as a result of the crimson (ogc ) gene (Thompson et al., 1965). Flavor is superior to most commercially available tomato cultivars based on the results of seven experienced sensory panels, a consumer panel, and numerous samplings from field trials. Environmental conditions have a large impact on tomato flavor (Scott, 2001), and the strength of this hybrid is its ability to

Free access

E.A. Baldwin, J.W. Scott, M.A. Einstein, T.M.M. Malundo, B.T. Carr, R.L. Shewfelt, and K.S. Tandon

The major components of flavor in tomato (Lycopersicon esculentum Mill.) and other fruit are thought to be sugars, acids, and flavor volatiles. Tomato overall acceptability, tomato-like flavor, sweetness, and sourness for six to nine tomato cultivars were analyzed by experienced panels using a nine-point scale and by trained descriptive analysis panels using a 15-cm line scale for sweetness, sourness, three to five aroma and three to seven taste descriptors in three seasons. Relationships between sensory data and instrumental analyses, including flavor volatiles, soluble solids (SS), individual sugars converted to sucrose equivalents (SE), titratable acidity (TA), pH, SS/TA, and SE/TA, were established using correlation and multiple linear regression. For instrumental data, SS/TA, SE/TA, TA, and cis-3-hexenol correlated with overall acceptability (P = 0.05); SE, SE/TA (P≤0.03), geranylacetone, 2+3-methylbutanol and 6-methyl-5-hepten-2-one (P = 0.11) with tomato-like flavor; SE, pH, cis-3-hexenal, trans-2-hexenal, hexanal, cis-3-hexenol, geranylacetone, 2+3-methylbutanol, trans-2 heptenal, 6-methyl-5-hepten-2-one, and 1-nitro-2-phenylethane (P≤0.11) with sweetness; and SS, pH, acetaldehyde, aceton, 2-isobutylthiazole, geranlyacetone, β-ionone, ethanol, hexanal and cis-3-hexenal with sourness (P≤0.15) for experienced or trained panel data. Measurements for SS/TA correlated with overall taste (P=0.09) and SS with astringency, bitter aftertaste, and saltiness (P≤0.07) for trained panel data. In addition to the above mentioned flavor volatiles, methanol and 1-penten-3-one significantly affected sensory responses (P = 0.13) for certain aroma descriptors. Levels of aroma compounds affected perception of sweetness and sourness and measurements of SS showed a closer relationship to sourness, astringency, and bitterness than to sweetness.

Open access

Dwain D. Gull, Peter J. Stoffella, Salvador J. Locascio, Steve M. Olson, Herbert H. Bryan, Paul H. Everett, Teresa K. Howe, and John W. Scott

Abstract

Ten fresh-market tomato (Lycopersicon esculentum Mill.) genotypes were evaluated for stability of fruit firmness, citric acid, soluble solids, β-carotene and ascorbic acid concentrations, sugar : acid ratio, color, N content, and dry weight when grown in nine environments. Linear relationships between the genotype means for a given trait and the mean for the trait in each environment were used as an indicator of stability. A stable genotype for a given trait was considered to possess a regression coefficient (b1) ⩽ a coefficient of linear determination (r2) > 0.50, a genotype mean above the grand mean (mean of all genotypes), and a nonsignificant deviation from regression mean square (S2d). Using these criteria, stability in the nine environments was shown by the fruits of the various cultivars as follows: ‘Flora-Dade’, ‘FTE-12’, and D76I27 for firmness; ‘Castlehy 1035’ and ‘Sunny’ for citric acid; ‘Walter’ for soluble solids concentration; ‘FTE-12’ for ascorbic acid concentration; ‘Hayslip’, ‘Walter’, and ‘Burgis’ for sugar : acid ratio; ‘FTE-12’ and ‘Hayslip’ for β-carotene concentration: ‘Flora-Dade’ and 827115-IBK for color a/b; ‘Castlehy 1035’ and ‘Hayslip’ for dry weight; and ‘Walter’ for N content. Stable genotypes are less sensitive to environmental changes and are more adapted to favorable and unfavorable conditions than unstable genotypes. No genotype was found to be stable for every fruit quality trait in the nine environments. Stability of fruit quality characteristics should be considered in tomato breeding programs to develop genotypes adapted to diverse environmental and management conditions.

Free access

Todd C. Wehner and Beiquan Mou

Crop listings: asparagus, bean–dry, bean–green, beet, broccoli, cabbage, cabbage–Chinese, carrot, cauliflower, celery, collard, cucumber, eggplant, endive, herbs–parsley, leek, lettuce, melon, okra, onion, pea–green, pepper, pumpkin, radish, rhubarb, soybean, spinach, squash, sweetcorn, Swiss chard, tomato, turnip, watermelon.

This list of the North American vegetable cultivars was developed using the database of cultivars registered with the American Seed Trade Association, as well as published descriptions from scientific journals, seed catalogs, and websites of seed companies. Assistant editors responsible for each crop were instructed to obtain as much information as possible about the cultivars available to North American growers. The crop species