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David L. Coffey

Eight extended shelf-life hybrid tomato cultivars, along with six conventional entries including the commercial cultivars, `Sun Leaper' and `Plum Dandy', were evaluated at The Univ. of Tennessee Agricultural Experiment Station. Plants of extended shelf-life cultivars had an indeterminate growth habit and were 18 cm taller than plants of the determinate conventional cultivars. Subjective ratings for disease incidence were less for extended shelf-life cultivars early in the season but were no different late in the season. Fruits were harvested at the pink stage over a 4-week period and graded by size according to the Los Angeles lug arrangement. Yields from extended shelf-life cultivars ranged from 2000 to 2666 with an average of 2394 boxes of marketable fruit per hectare. Yields from conventional cultivars averaged 2323 boxes of marketable fruits per hectare. Yields of fruits occurring in the 5 × 5 and larger size ranges were greater for the extended shelf-life cultivars, while the reverse was true with yields of fruits in the 6 × 6 range. Extended shelf-life cultivars produced more cull fruits than conventional cultivars. For firmness comparisons, fruits were selected from the 4 × 5 grade and stored at a temperature of 22 to 24 °C. Starting 2 days after harvest, fruits were subjectively evaluated at 2-day intervals by hand-squeezing, using a rating scale of 1-5, 5 being equivalent to that of the firmness of a mature green fruit of the same size category. Fruits of extended shelf-life cultivars were firmer at harvest and remained firmer during 12 days of postharvest storage than those of conventional cultivars.

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David L. Coffey

Results from a three-year cultivar evaluation study indicate that Chinese cabbage production is feasible in Tennessee, but may require special attention to bacterial disease control. Individual head weight and projected yields of both the heading (pe tsai) and the nonheading (pak choy) forms compared well to those reported from areas where it is adapted and widely grown. Additional research is needed to identify appropriate planting dates and slow-bolting cultivars, especially for spring production. The ability to achieve predictable and profitable spring and fall production of this specialty crop is essential for establishing markets and promoting Chinese cabbage as a reliable crop that can be incorporated readily into vegetable production systems.

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Joanne Logan and David L. Coffey

Vegetable production has become a multi-million dollar activity in Tennessee. The large number of options of planting dates and maturity classes of different vegetable species and cultivars result in a flexible, yet confusing, situation for the grower. A plentiful supply of vegetables for the processor, fresh market, or family table can be assured by the proper scheduling of planting and harvest of different crops and cultivars. Growers have very limited access to climatic data oriented to vegetable production in their locations. For the most part, they depend on planting maps on the backs of seed packets, or on extension bulletins with very general planting and harvest date recommendations. Tennessee consists of 4 climatic divisions that do not adequately describe the multitude of climates due to the diverse topography. The objective of this research was to create GIS maps of climatic variables important to vegetable production. Maps of temperatures, growing degree days, and rainfall, freeze and heat stress probabilities based on data from 72 locations in Tennessee were used to characterize the growing seasons for different vegetables.

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William Terry Kelley and David L. Coffey

Three cropping sequences and three tillage systems were evaluated under reduced tillage. Sequences were spring `Packman' broccoli followed by `Sunny' tomatoes or 'm.s. Ky 14 × L8 tobacco, spring broccoli/tomatoes or tobacco/fall broccoli, and tomatoes or tobacco/fall broccoli. Each sequence was grown conventionally tilled/no winter cover, conventionally tilled/wheat winter cover and no-till transplanted directly into killed wheat. The study was conducted at Knoxville, (elev. 251m), Greeneville, (elev. 400m) and Crossville, (elev. 549m) during 1989 and 1990. Experiments were arranged in a strip-plot design with sequences stripped across tillages. No. 1 tomato yield was reduced in no-till at Greeneville (1989). Percentage of No. 1 tomatoes was not affected by tillage but the tomato-broccoli system produced a greater percentage at Greeneville (1990). Broccoli head size and subsequent yield was generally greater in conventionally tilled plots. Sequence generally had little affect on broccoli production. Yield and revenue of tobacco were generally lower in no-till treatments. Broccoli/tobacco sequences generally had the highest yield but varied by location. No-till produced lower quality tobacco both years at Knoxville but not at Greeneville.

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William Terry Kelley and David L. Coffey

Three cropping sequences and three tillage systems were evaluated for increasing returns on small farms under reduced tillage. The sequences were spring 'Packman' broccoli followed by 'Sunny' tomatoes, spring broccoli/tomatoes/fall broccoli, and tomatoes/fall broccoli. Each sequence was grown conventionally tilled with no winter cover, conventionally tilled with a wheat winter cover and no-till transplanted directly into killed wheat. The study was conducted at Knoxville, TN (elev. 251m, Greeneville, TN (elev. 400m) and Crossville, TN (elev. 549m) during 1989 and 1990. Experiments were arranged in a strip plot design with sequences stripped across tillage treatments. No. 1 tomato yield was reduced in no-till at Greeneville (1989). Percentage of No. 1 tomatoes was not affected by tillage but the tomato-broccoli system produced a greater percentage at Greeneville (1990). Percentage of cull fruit was greater in Knoxville (1990) for conventional/no cover. A tomato-broccoli sequence produced more cull fruit at Knoxville (1990) and Greeneville (1989). Broccoli head size and subsequent yield and value was generally greater at most environments in conventionally tilled plots. Sequence generally had little affect on broccoli production.

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Vernon H. Reich and David L. Coffey

Float bed culture, common in the production of tobacco transplants, was investigated for the production of the salad vegetables leaf lettuce and radicchio. Experiments were conducted during Spring and Summer 1999. Seeds were planted on 61 cm × 61 cm, 2.54-cm-thick expanded foam sheets and floated on nutrient solution until plants were ready for harvest. Lettuce plants of the four cultivars evaluated were harvested 53 days after planting. Yields ranged from 99 to 181 g/plant. In the same experiment, aeration of the solution was compared with static solution with plants grown in aerated nutrient solution yielding significantly better than those grown in static solution. There was not a significant cultiva × aeration interaction for yield. Radicchio plants were seeded on expanded foam sheets at 20 plants per sheet. Plants were harvested 69 days after seeding. Those that had been aerated had significantly higher number of heads and leaf, head, and root weight than the nonaerated ones. There were no differences in total leaf weight among the five cultivars evaluated, but `Red Treviso' had significantly fewer and lower weight heads and more root weight than the other four cultivars.

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Senshan Yang, Joanne Logan and David L. Coffey

To investigate effects of temperatures in the preceding developmental stage on the following developmental stage, `Sunny' tomatoes were seeded in the greenhouse at six dates and three temperature levels. Plants were rotated among temperature levels so that all plants received approximately the same temperature accumulation at the time of field transplanting. Developmental stages defined were: emergence, 1st, 2nd, 3rd, 4th, 5th, and 6th leaf appearance. Temperature and solar radiation were recorded hourly. Results indicated a significant effect of temperature in the preceding stage on the following stage. Coefficients of variation (CV) in growing degree days (GDD) calculated from the 1st to the ith stage were significantly smaller than those calculated from the (i-1)th to ith stage. When Ri, defined as the reciprocal of the number of days from the 1st to the ith stage, was regressed to Ri-1 and the daily average temperature was regressed from the (i-1)th to the ith stage, all coefficients of Ri-1 were significant at the 1% level. This model was superior to one in which Ri was regressed to the daily average temperature from the 1st to the ith stage.