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Stephen Reiners and Peter J. Nitzsche

`Pilgrim' tomatoes (Lycopersicon esculentum) grown under slitted clear polyethylene or spunbonded polypropylene rowcovers were compared to those with no protection for the effect on yield. Both covers significantly increased early yield in terms of fruit numbers and weight, but no differences were observed in total yields. In addition, no difference was observed in yield between two tomato transplant sizes- 4- to 5-leaf stage and 6- to 7-leaf stage---grown in the same-sized containers. The results from this study indicate that early tomato yield may be enhanced with the use of rowcovers.

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T.J. Swiecki and J.D. MacDonald

Exposure of tomato plants (Lycopersicon esculentum Mill.) to salinity stress either before or after inoculation with Phytophthora parasitica increased root and crown rot severity relative to nonstressed controls. The synergy between salinity and P. parasitic was most pronounced on young (prebloom) plants and least pronounced on older (postbloom) plants. Salt stressed, inoculated plants had significantly reduced top weight, significantly more root necrosis, greater incidence of crown necrosis, and significantly greater mortality. Increased disease severity occurred even though experiments showed salinity reduced zoospore release arid motility of P. parasitic, suggesting that even low inoculum levels can result in severe root rot on young tomato plants in saline soils.

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Joseph. M. Kemble and Randolph G. Gardner

Experiments were conducted in 1989 to determine the heritability of shortened fruit maturation (SFM) period in 871213-1, an inbred cherry tomato line (Lycopersicon esculentum var. cerasiforme (Dunal.) A. Gray), and to determine the relationship between this trait and fruit size. In the first study, a cross was made between 871213-1 and NC 21C-1, an inbred cherry line. NC 21C-1 had a mean maturation period of 40.8 days compared to 32.0 days for 871213-1. A mean maturation period for the F1 hybrid of 32.9 days and 32.2 days was found using 871213-1 as the female and male parent, respectively. Analysis of the data from parental, F1, F2 and backcross generations yielded estimates of broad-sense and narrow-sense heritabilities for SFM as 0.72 and 0.56, respectively. Further analysis indicated that genetic control of SFM was quantitative in nature and highly dominant. A test for epistatic interaction showed significance. In the second study, an F2 population from the cross 871213-1 x NC 309-1, a large-fruited tomato line (Lycopersicon esculentum Mill.), was evaluated to determine if any correlations existed between fruit size and SFM. Two fruit characteristics, locule number and fruit weight, were used as estimates of fruit size. Correlations between SFM and these two characteristics were +0.28 and +0.61, respectively. Broad-sense heritability of SFM was estimated as 0.64.

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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.

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W.B. Evans, Y. Vizzier-Thaxton, P. Hudson, and K. Paridon

Mississippi is one of the nation's largest broiler litter producing states. Interest in using litter and other organic waste products, such as compost, in horticultural systems is increasing in the state and region. The objective of this research was to determine the influences of composted broiler litter (CBL) on three aspects of vegetable crop productivity: growth and yield, microbiological safety, and mineral nutrition. This report focuses on the first two objectives. Compost was made in a covered, turned windrow for a blend of broiler litter and hardwood sawdust. Responses to CBL were tested in two vegetables: collard (Brassica oleracea var. Acephala) and tomato (Lycopersicon esculentum). Rates of CBL ranged from 0 to 5 tons/acre, preplant incorporated in a randomized complete block design with four replicates for each species in two separate experiments in 2004. Testing of the CBL, the soil after application, leaves, and harvested organs found no significant influence of CBL on pathogenic microbe concentrations. At each of five sampling dates through commercial crop maturity, collard (Brassica oleracea var. Acephala) fresh and dry weight per plant increased linearly with CBL applications up to 5 tons/acre. Tomato (Lycopersicon esculentum) shoot fresh weight increased with increasing CBL applications at each sampling date. Marketable fruit yield increased linearly with increasing CBL applications. Total fruit yield response to CBL was best described by a quadratic equation.

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H.C. Wien and Y. Zhang

Catfacing of tomato (Lycopersicon esculentum Mill.) fruit describes the enlarged blossom-end scar and ridged, flattened or irregular fruit shape often found on plants subjected to low temperature during ovary development. Experiments were conducted to determine if GA3 foliar sprays could be used as a screening tool for catfacing. Concentrations of 5 to 50 μM of GA3, applied once at transplanting, significantly increased catfacing incidence on the susceptible `Revolution', whereas the resistant `Valerie' was less affected. Two applications 8 days apart extended symptoms to later clusters formed on branches and may be useful for screening cultivars of a wide range of earliness. Plant apex removal may also be possible as a fruit catfacing screening tool. Chemical name used: gibberellic acid (GA3).

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Linda Nelson and K.A. Stewart

In 1988 and 1989, three tomato (Lycopersicon esculentum Mill.) cultivars, Springset (cold-tolerant), Celebrity (standard) and Hope No. 1 (heat-tolerant) were grown under clear and white perforated mini-tunnels that were either vented ten days prior to anthesis to maintain temperatures below 29°C or non-vented. Controls had no mini-tunnel treatment. Maximum temperatures were highest under the clear-nonvented tunnels. Minimum temperatures were lower in the clear and white vented tunnels compared to the control and non-vented tunnels in 1989. Springset had the highest early and Celebrity the highest total yield .The clear non-vented tunnels gave significantly lower early yields compared to the other tunnel treatments in 1988. In 1989, treatments had no effect on early yield. The percentage of early yield that was marketable varied from 58-82 % in 1988 and 72-85% in 1989. For both years, total yields did not differ significantly.

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Allen V. Barker, Kathleen M. Ready, and Jinan Feng

Several factors inducing physiological stress in plants were investigated for their effects on foliar ammonium accumulation and ethylene evolution in tomato (Lycopersicon esculentum Mill.). Plants grown on ammonium nutrition (0.015M NH4 +) in solution culture had elevated rates of ammonium accumulation and ethylene evolution relative to plants grown on nitrate nutrition at the same molar concentration. Inhibitors of ethylene action (0.001 mM Ag+) or synthesis (0.01 mM amino-oxyacetic acid) restricted ammonium accumulation and ethylene evolution relative to rates by untreated controls receiving ammonium nutrition. The inhibitors lessened the expression of ammonium toxicity. Stress from salinity, drought, or flooding in soil increased ammonium accumulation and ethylene evolution. Plants infected with root-knot nematode had variable rates of ethylene evolution in response to variations in ammonium accumulation. Ammonium accumulation and ethylene evolution appear to be factors in the expression of physiological stress.

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D.T. Drost and H.C. Price

Tomatoes (Lycopersicon esculentum Mill.) were grown in conventional tillage (CT), rye (Secale cereale L.) mulch no tillage (RNT), and wheat (Triticum aestivum L.) mulch no tillage (WNT). Either germinated seeds (GS) or raw seeds (RS) were fluid drilled on several dates in 1981 and 1982. Tomato stands in no tillage (NT) generally were equal to or higher than in CT, and stands improved with later plantings in each year. Plant stands were unaffected by GS and RS. Time to 50% emergence (T50) was up to 4 days less in NT than in CT and 2 to 3 days less from GS than RS. Yields with CT were twice as high as those with NT for early planting dates. Yields decreased in CT with successive planting dates to levels equal to NT plantings. Use of GS increased fruit yields as compared to RS, regardless of the planting date.

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Wilton P. Cook and Douglas C. Sanders

Studies were conducted to determine the effect of N application frequency through drip irrigation on soil NO3-N movement in the bed profile and on yield and N uptake by tomato plants (Lycopersicon esculentum Mill. `Sunny') at two locations. Increasing N application frequency resulted in increased yields at Clayton, N. C., but not at Charleston, S.C. The number of fruit produced was not affected by N treatment at either location, but fruit size increased with increasing N application frequency at Clayton. Foliage N concentration decreased seasonally, but neither foliage N concentration nor total N content of the above-ground portion of the plants was affected by N application frequency. Regardless of N application frequency, NO3-N concentrations within the raised bed decreased with time due to plant uptake and leaching. Nitrogen levels declined most rapidly in the area closest to the drip tube.