significant amounts of minerals and fiber. In Kenya, tomatoes always are in high demand both for fresh consumption and processing ( Mungai et al., 2000 ). Tomato are established by direct seeding or from transplants ( Long and Cantliffe, 1975 ). However
Elisha O. Gogo, Mwanarusi Saidi, Francis M. Itulya, Thibaud Martin, and Mathieu Ngouajio
Berl M. Thomas
The containerized transplant commercial industry started in the United States in the 1960's. Since then, several different types of growing containers have been developed for the vegetable, tobacco, ornamental and forestry seedling industries. Two basic irrigation methods have developed including overhead and sub-irrigation systems. The irrigation system used depends on the crop needs, value, availability of water, and the need to reduce pesticide use and risk of disease. Sub-irrigation systems have reduced the spread of seed-borne and naturally occurring diseases. Overhead irrigation systems were predominantly used during the early years, but at present, both systems are used and selected for their respective advantages. Future developments in the transplant industry include reduction of production risks and to improve cost per production unit by reducing both nursery and farm labor requirements.
Francis X. Mangan, Charles S. Vavrina, and John C. Howell
The effects of transplant depth on lodging and yield were evaluated in five experiments in Florida and Massachusetts. `Cherry Bomb', `Jupiter', and `Mitla' pepper (Capsicum annuum L.) transplants were set at three depths so that the soil surface was even with the top of the rootball, the cotyledon leaf, or the first true leaf. Seedlings set to the depth of cotyledon leaves or to the first true leaf lodged less than did those set to the top of the rootball. No yield differences were recorded among treatments in Massachusetts; however, total weight of red fruit was greater in treatments that lodged less in 1 of the 2 years, suggesting that lodging delayed maturity. Soil temperature in Massachusetts declined at the level of the rootball as planting depth increased.
Steven C. Adams
Seed vigor has a very subtle effect on the productivity of greenhouses producing vegetable transplants, celery, cauliflower, lettuce, etc. and on todays highly mechanized automatic or semi-automatic transplanting operations. As greenhouse production technology moves from traditional bare root to plug/tray growing systems and as automatic and semi-automatic transplanting operations increase in number, the impact of poor seed vigor is realized.
Measures to mitigate the impact of poor seed vigor in the nursery are: Seed density grading; increased growing cycle in the nursery, hand culling or replanting. Measures to mitigate the impact of poor seed vigor in automatic transplanting operations: increase the number of people following the planter to replace poor vigor plants; use hand fed transplanters.
Joyce G. Latimer
Since chemical growth retardants are no longer labelled for use on vegetable transplants, mechanical conditioning provides an alternative method of controlling excessive stem elongation under greenhouse conditions. Mechanical conditioning includes brushing or shaking treatments that physically impact or displace the plant and generally reduce plant growth, increase stem and petiole strength, and improve overall plant quality. The resulting transplants have less breakage during postharvest handling, may be more stress tolerant, and are faster to establish in the field. However, only minor effects on crop yield have been identified. Brushing reduced broccoli transplant size, but improved shoot dry weight gain during field establishment but had no effect on head yield. Brushing is a labor intensive practice for large-scale operations. Current attempts to mechanize brushing require that the plants are uniform in height and treatment tolerant. Additional research in non-contact treatments like shaking or vibration of benches is necessary. The effects of the treatments on stress tolerance and predisposition to disease need to be clarified.
Laurie Hodges, Entin Daningsih, and James R. Brandle
Field experiments were conducted over 4 years to evaluate the effects of antitranspirant (Folicote, Aquatrol Inc., Paulsboro, N.J.) and polyacrylamide gel (SuperSorb, Aquatrol Inc., Paulsboro, N.J.) on early growth of transplanted muskmelon grown either protected by tree windbreaks or exposed to seasonal winds. A randomized complete block design (RCBD) with split plot arrangement was used with wind protection (sheltered and exposed) areas as the main treatment and use of an antitranspirant spray or gel dip as subtreatments. Based on destructive harvests in the field, treatments and subtreatments did not affect dry weight or leaf area index in the first 2 years. Specific contrasts, however, showed that gel application significantly increased fresh weight, dry weight, and leaf area index over that of the untreated transplants whereas the spray application tended to reduce these factors during the first 3 weeks after transplanting. Significant differences between gel and spray subtreatments disappeared by 5 weeks after transplanting. Shelterbelts ameliorated crop microclimate thereby enhancing plant growth. Significantly, wind velocity at canopy height was reduced 40% on average and soil temperatures were about 4% warmer in the sheltered plots compared to the exposed plots during the first 5 weeks post-transplant. Muskmelon plants in the sheltered areas grew significantly faster than the plants in the exposed areas in 2 of the 3 years reported, with the 3-year average fresh weight increased by 168% due to wind protection. Overall transplanting success and early growth were enhanced the most by wind protection, followed by the polyacrylamide gel root dip, and least by the antitranspirant foliar spray. We conclude that microclimate modification by wind speed reduction can increase early muskmelon plant growth more consistently than the use of polyacrylamide gel as a root dip at transplanting or the use of an antitranspirant spray. A polyacrylamide gel root dip generally will provide more benefit during early muskmelon growth than the use of an antitranspirant spray.
Regina P. Bracy
Field studies were conducted in Spring 1991, 1992, and 1993 to determine if stand deficiencies of 10%, 20%, or 30% affected bell pepper (Capsicum annuum L.) yield and fruit size. Subsequent replanting to a 100% stand and timing of replanting also were evaluated for effects on fruit yield. Stand deficiencies of up to 30% and replanting to a complete stand 2 or 3 weeks after initial transplanting did not affect yield per acre and average weight per fruit of bell pepper plants grown on polyethylene-mulched beds during 3 years of tests. Bell pepper plants grown in 10%, 20%, or 30% deficient stand had greater marketable yield per plant than plants grown in 100% stand. Replanting to a complete stand 3 weeks after initial transplanting decreased early marketable yield and production per plant over replanting 2 weeks after initial transplanting.
Darren E. Robinson, Kristen McNaughton, and Nader Soltani
cultivated twice with a field S-tine cultivator and rolling basket harrows in the spring before transplanting. The experimental design was a randomized complete block split-plot design with four replications. The main plot treatments were s
Joyce G. Latimer
`Jupiter' or `Marengo' pepper (Capsicum annuum L.) seedlings maintained under 0%, 30%, 50%, or 80% shade in a greenhouse were brushed 80 strokes twice daily beginning at the cotyledonary, first true leaf, or second true leaf stage. Averaged across shade environments, brushing reduced `Jupiter' and `Marengo' stem length 25% to 36% and 6% to 28%, respectively. However, the percentage of plants exhibiting mechanical damage by brushing ranged from 86% to 93% and 48% to 90% for `Jupiter' and `Marengo', respectively. Transplant quality tended to decrease as brushing was delayed. When brushing of `Marengo' was reduced to 40 strokes twice daily in 1992, plant growth reduction decreased, but the percent damage was about the same. The damage severity, however, was reduced as indicated by higher plant-quality ratings. Pepper plant damage was excessive for the small amount of growth regulation provided by brushing.
Charles W. Marr and Mark Jirak
Tomatoes (Lycopersicon esculentum Mill. cv. Jet Star) seedlings grown in small cells (plugs) in trays holding 200, 406, or 648 plants per flat (28 × 55 cm) were larger after 6 weeks as cell size increased, but all were acceptable. Other seedlings, transplanted at weekly intervals from plug trays to plastic cell packs (48 cells per 28 × 55-cm flat), were of similar size during weeks 1-3; seedlings from 648-plug trays were smaller than the others by week 5-6. Seedlings from 200-plug trays planted at weekly intervals into containers where plant-plant competition was absent were larger through 6 weeks than those from 406- and 648-plug trays. Early marketable and total yields were similar for plants held in 406-plug trays 1 to 4 weeks before their transfer to 48-cell flats, but yield decreased for those held 5 to 7 weeks.