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Ruben Macias-Duarte, Raul Leonel Grijalva-Contreras*, Manuel de Jesus Valenzuela-Ruiz, and Fabian Robles-Contreras

The onion bulb production In Mexico is about 39,000 ha annually. Yield is variable according to the technological capacity and economic condition of the grower. However, The technology adoption (new varieties, efficient irrigation system and establishment methods) is increased during the last years. Traditionally in Mexico the grower use the manual transplant of seedling, that which increases the cost and time of this labor. The objective of the present Experiment was to evaluate Two establishment methods (direct seed and transplant seedling) and the effect on 24 bulb varieties. The evaluation was carried out in INIFAP-CIRNO Experimental Station in furrows with 1.00 m of separation among them, with double row of plants, the amount of nitrogen and phosphorus used were 180 and 80 kg·ha-1 respectively, we used the drip irrigation system. In this experiment we observed that the system of direct seed obtained better yield (18%), bulb weight (21%) and precocity (11 days) in comparing to the transplant methods, however in the first treatment the floral stem emission was greater (6.7% vs 1.1%) of the transplant methods. The white varieties with high yield were: White onion 214 and Cal 128 with 71.4 and 65.7 ton/ha. The purple varieties was F1 Cal 192 with 68.3 t·ha-1 and the yellow varieties was Ringer Cal 160 with 63.2 t·ha-1.

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Regina P. Bracy and Richard L. Parish

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.

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Mike Murray

The California processing tomato industry continues to utilize transplants as a primary method of obtaining final plant stands. About 75% of the anticipated 2006 acreage will be transpanted, up from 0% a scant 20 years ago. This trend is being driven by increasing hybrid seed costs, the desire to utilize the land for multiple crops per year, potential water savings, and enhanced weed management options. The history of this transition will be traced, identifying positive and negative impacts of reliance on transplants. An economic evaluation suggests that stand establishment using transplants costs at least $250 per acre more than direct-seeding. A cost-benefit analysis is considered. The movement to transplants has reduced seed sales and many hybrid seed variety prices are tripling in 2006, as seed companies attempt to recoup R&D costs with declining markets. This “differential seed pricing,” and its implications, are discussed in detail.

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J. Cavero, R. Gil Ortega, and M. Gutierrez

Paprika pepper (Capsicum annuum var. annuum L., `Agridulce SIA') was direct-seeded on raised beds in double rows 0.35 cm apart. Plants were thinned within the row to establish densities ranging from 13,333 to >500,000 plants/ha. Yield of paprika pepper increased as plant density increased, but plant densities >200,000 plants/ha resulted in only small increases in yield. Fruit number and dry fruit weight/plant decreased with increasing plant populations, and weight/fruit decreased slightly. The increase in yield/ha as plant density increased was a result of increased numbers of fruits/ha. Pigment content (ASTA units) declined linearly as plant density increased, whereas moisture content of red fruits at harvest remained unaffected. Plant densities in the range of 150,000 to 200,000 plants/ha were optimal in terms of fruit yield and pigment content.

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Gene M. Miyao, Dennis C. Bryant, Mark S. Kochi, and Israel G. Herrera

Canning tomato transplants were compared to direct seed in field trials to evaluate fruit yield and quality. Trials were conducted either at the University of California at Davis Long Term Research on Sustainable Agriculture field facility or in a commercial direct-seeded tomato field near Woodland. To closely match harvest dates of both propagation methods, transplants were mechanically planted after direct-seeded plants approached the 2 to 3 true-leaf stage. Trial design was replicated, factorial with propagation method and with plant population comparisons. Populations were 8712, 6534, 5227, and 4356 planting units per acre. Direct-seeded plots were thinned to clumps of three plants centered on 12, 16, 20, or 24 inches between clumps within the seed line. Transplants were 6-week-old, commercial, greenhouse-grown plants that were mechanically planted to match the direct-seed spacing. Plant rows were single lines per bed centered on 5 feet. The entire 100-foot plot length was mechanically harvested into specially designed portable weigh trailers to measure yield. Fruit yield between direct-seed and transplants were similar in two of the 3 years. In one of the 3 years, production problems were encountered resulting in low overall yield, but significantly lower with the transplants. `Halley', a cultivar common in the region, was used in all of the test years. Transplant yields were slightly reduced linearly as spacing between plants increased while yield from direct seed was less affected. Fruit quality tended to be similar among the treatments.

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Charles L. Webber III, James W. Shrefler, and Merritt J. Taylor

.7%) broadleaf weed control through the first 46 d after planting (DAP) ( Webber et al., 2007a ), without reductions in yields from crop injury ( Webber et al., 2007b ). The impact of CGM applications on the plant safety of direct-seeded crops has been

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Daniel S. Egel, Ray Martyn, and Chris Gunter

, 2007 ). It is not known how development (vine growth and root structure) and yield are affected by today's practices compared with direct seeding on nonfumigated bare ground. Although one study of triploid watermelon root systems found no aberrant

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Daniel I. Leskovar, J. Clark Ward, Russell W. Sprague, and Avraham Meiri

Restrictions on pumping water from underground aquifers are limiting vegetable production in Southwest Texas. To determine yield, quality, and water use efficiency (WUE) of muskmelon (Cucumis melo L. group Cantalupensis, `Caravelle'), six irrigation systems with varying input levels and their interactions with stand establishment (containerized transplants vs. direct seeding) were examined. Irrigation systems were: 1) pre-irrigated followed by dryland conditions; 2) furrow/no mulch; 3) furrow/mulch (40-μm-thick black polyethylene); 4) surface drip (0 cm depth)/mulch; 5) subsurface drip (10-cm depth)/mulch; and 6) subsurface drip (30-cm depth)/mulch. Field experiments were conducted on a silty clay loam soil during four seasons (1995-98). In 1995, marketable fruit yields were greater for subsurface drip systems at 30-cm depth than for furrow systems, with or without plastic mulch. Transplants grown with surface drip irrigation produced 75% greater yield in the 9-count fruit class size during early harvest than did those grown with subsurface drip (10- or 30-cm depth), but total yield was unaffected by drip tape depth placement. In 1996, the driest season of these studies, direct-seeded plants had higher total yields than did transplants; yield was greatest for direct-seeded plants on subsurface drip placed at 10- or 30-cm soil depth, and for transplants on subsurface drip at 10-cm depth. Soluble solids content was minimally affected by irrigation method, but was higher in fruit from transplants than in those from direct-seeded plants in 3 years. Across all seasons, the average water applied for drip systems was 53% lower than that for conventional furrow systems, and WUE was 2.3-fold as great.

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Joseph Aguyoh, Henry G. Taber, and Vince Lawson

Sweet corn (Zea mays L.) growers in the upper midwestern U.S. have used clear plastic mulch to improve early yield and advance crop maturity. Results of this practice have been inconsistent because of early season temperature variability and inadequate information on cultivar adaptation. Our objective was to improve the performance consistency by investigating earliness techniques with the early, sugary-enhancer (se) cultivar Temptation planted at two sites. Treatments were bare soil or clear plastic mulch, rowcovers or none, and direct-seeded or transplanted plants. Transplants were produced in the greenhouse in either 50-cell plastic trays or peat pot strips, 2.3 inches × 4.0 inches deep (6 × 10 cm) and were evaluated according to transplant age and cell size. In the cold springs of 1996 and 1997, the use of clear plastic mulch shortened maturity of sweet corn by 1 and 10 days, respectively, for the silt loam site; but no maturity advantage was observed for the loamy sand site. Clear plastic raised the minimum soil temperature by 3.8 to 4.0 °F (2.1 to 2.2 °C) at both sites. The 2-week-old 50-cell tray transplants matured 6 days earlier than the peat pot strip transplants or direct seeded at both locations in 1997. Marketable yield from the transplants was inconsistent by location and year. Four-week-old transplants did not withstand field stress and performed poorly regardless of type of container. Ear quality as indicated by row number, ear diameter, ear length, and tipfill was lowest with transplants.

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Gregory E. Welbaum, Jonathan M. Frantz, Malkanthi K. Gunatilaka, and Zhengxing Shen

Sweet corn (Zea mays L.) cultivars containing the shrunken-2 (sh2) gene have superior kernel quality but often germinate poorly and display poor seedling vigor. The transplanting of sh2 sweet corn was investigated as a method to improve stand establishment and hasten maturity. Three-week-old plants (sh2 cv. Krispy King) were raised in 200-cell polystyrene trays in either plug-trays (PT), float beds (FB), or ebb-and-flood (EF) production systems and compared with direct-seeded (DS) controls for transplant quality, successful establishment, and early harvest. In 1994, when plants were established in early June, PT plants matured 1 week earlier than DS and FB plants, which had similar mean times to harvest. In 1995, when field planting occurred in July, all plants flowered prematurely when only 60 cm tall. In 1996, the experiment was begun in early May, and survival of all transplants was >85% vs. 54% for DS plants. In 1996, transplants matured 10 to 13 days earlier than DS plants, however, >90% of DS plants produced marketable ears vs. 63%, 49%, and 44% of EF, FB, and PT plants, respectively. The DS plants were also taller with better root development than transplants in all years. Transplants produced smaller, lower-quality ears than did DS plants, thus nullifying the benefits of greater plant populations and earlier maturity. The EF system produced high-quality seedlings because of the greater control of water availability during seedling development. In some areas, the increased value of early sh2 sweet corn may be worth the additional cost of transplanting and greater percentage of unmarketable ears.