Onion (Allium cepa var. cepa L.) is extensively grown under furrow irrigation in the western United States. Wheel compaction of furrows increases water runoff and erosion, and can lead to poor lateral water movement and reduced yields. We studied the effects of 560 to 800 lb/acre (630 to 900 kg·ha-1) wheat straw mechanically applied to the bottom of irrigation furrows on yield and bulb size of sweet Spanish onions in commercial onion fields in 1988, 1990, and 1991, and at an experiment station in 1991 and 1995. Furrows in commercial fields were either compacted with tractor wheels or not. In the commercial fields, straw application increased onion yield in plots with compacted furrows in 1988 and in all plots (with or without compacted furrows) in 1990. At the experiment station, straw mulch increased onion yield 64% in 1991, and 74% in 1995. Straw application primarily increased yields of jumbo (3 to 4 inches; 76 to 102 mm) and colossal (>4 inches; 10 cm) onions, whereas there was no effect on medium (2.25 to 3 inches; 57 to 76 mm) onions. We attributed yield improvements to decreased water runoff and increased lateral water movement and soil moisture.
C.C. Shock, L.B. Jensen, J.H. Hobson, M. Seddigh, B.M. Shock, L.D. Saunders and T.D. Stieber
Clinton C. Shock, Erik Feibert and Lamont D. Saunders
Onion (Allium cepa) cultivars for commercial production in eastern Oregon and southwestern Idaho are evaluated annually in replicated yield trials conducted at the Malheur Experiment Station, Oregon State University, Ontario. Market demand has progressively called for larger bulb size and bulbs with single centers. At harvest onions were evaluated for maturity, number of bolters, and single centeredness. Cultivars showed a wide range of bulbs with only one growing point or “bullet” single centers, ranging from 1% to 57% in 2000, from 7% to 70% in 2001, and from 1% to 74% in 2002. The percentages of bulbs functionally single-centered for processing uses ranged from 18% to 88% in 2000, from 24.7% to 91.3% in 2001, and from 14.4% to 92% in 2002. Bulb yield and market grade were evaluated out of storage. Marketable yield after 4 months of storage varied significantly by cultivar from 643 to 1196 cwt/acre (72.1 to 134.1 Mg·ha–1) in 2000, from 538 to 980 cwt/acre (60.3 to 109.8 Mg·ha–1) in 2001, and from 583 to 1119 cwt/acre (65.3 to125.4 Mg·ha–1) in 2002. Averaging over cultivars, super colossal bulb size averaged 26%, 14%, and 10% in 2000, 2001, and 2002, respectively.
Clinton C. Shock, Erik Feibert, Lynn Jensen, S. Krishna Mohan and Lamont D. Saunders
Onion (Allium cepa) varieties for commercial production in eastern Oregon and southwestern Idaho are evaluated annually in replicated trials conducted at the Malheur Experiment Station, Oregon State University, near Ontario, Oregon. Characteristics evaluated include bulb yield, market grade, and the frequency of single centers. After the emergence of iris yellow spot virus (IYSV) as a threat to commercial onion production in the early 2000s, onion varieties at the Malheur Experiment Station have been evaluated for virus symptoms since 2004. Varieties showed differences in the severity of IYSV symptoms each year. Symptom severity increased over the years from 2004 to 2006, and variety virus ratings showed a strong negative correlation of severity with yield in 2005 and 2006. Marketable yield after 3 months of storage averaged 781, 534, and 551 cwt/acre in 2004, 2005, and 2006, respectively. Averaging over varieties, yield of bulbs larger than 4 inches in diameter was 438 cwt/acre, 56 cwt/acre, and 76 cwt/acre, and the average virus severity ratings were 1.1, 1.3, and 2.7 in 2004, 2005, and 2006, respectively. A few varieties showed a combination of high yield, large bulb size, low incidence of virus symptoms, and a predominance of single-centered bulbs. With the prevalence of IYSV, variety tolerance to IYSV has become an important production factor in the Treasure Valley.
Clinton C. Shock, Joey K. Ishida, Eric P. Eldredge and Majid Seddigh
Potential new onion (Allium cepa L.) cultivars for commercial production in eastern Oregon and southwestern Idaho are evaluated annually in yield trials conducted at the Malheur Experiment Station, Oregon State University, Ontario, Ore. Bulb yield and market grade were determined in field trials for 63 yellow onion cultivars and lines in 1996 and for 49 cultivars and lines in 1997. Marketable yield out of storage in January ranged from 478 to 1131 cwt/acre (54 to 127 Mg·ha-1) in 1996, and from 383 to 912 cwt/acre (43 to 102 Mg·ha-1) in 1997. Marketable yields of `9003C', `Seville', `El Charro', `Sunre 1430', `El Padre', `Golden Security', `Bravo', and `X 202' were greater than 1000 cwt/acre (112 Mg·ha-1) in 1996. In 1997, marketable yields of `Seville', `Bravo', `Quest', `T-433', `9003C', `Goldstar', `Superstar', `RNX-10020', `Vision', and `Sweet Perfection' were greater than 850 cwt/acre (95 Mg·ha-1). Of the 30 cultivars evaluated both years, the average marketable yields of `Seville', 9003C, `Bravo', `Quest', and `Sweet Perfection' were among the highest. Many others showed potential for high yields and merit further evaluation. In both years, most bulbs of all selections graded jumbo [3 to 4 inch (7.6 to 10.2 cm) diameter] and colossal [>4 inch (10.2 cm) diameter], and only a few cultivars had more than 2% medium-size [2.25 to 3 inch (5.7 to 7.6 cm) diameter] bulbs. Infection by neck rot (Botrytis allii Munn.) and plate rot [Fusarium oxysporum f. sp. cepa (H. N. Hans.) W.C. Snyder & H.N. Hans.] during storage was more severe in 1996 than in 1997, but in general, most cultivars showed relatively low levels of these diseases in both years. Averaged across all cultivars, bolting was evident in less than 1% of bulbs in both years.
J.Z. Castellanos, P. Vargas-Tapia, J.L. Ojodeagua, G. Hoyos, G. Alcantar-Gonzalez, F.S. Mendez, E. Alvarez-Sanchez and A.A. Gardea
Depending on clove size and plant stand, planting represents a considerable proportion of the total production costs in garlic cultivation. The objectives of this study were to analyze the influence of seed clove size, planting density and planting method on yield, bulb size and on the profitability of garlic for the fresh market, planted under fertigation. Two experiments were established to evaluate planting densities ranging from 300,000 to 500,000 plants/ha in the 1998-99 season, and 300,000 to 600,000 plants/ha during the 1999-2000 season. Two additional experiments were established to evaluate the effect of seed size in the range of 1.9 to 10 g/clove in 1998-99, and 1.9 to 17 g/clove in 1999-2000. Seed of Taiwan-type `Tacatzcuaro' garlic was used in all the experiments. A fifth experiment was established to compare mechanical vs. hand planting. The experimental design in all cases was a randomized complete block with four replicates. For the plant density study, yields varied from 23.5 to 29.9 t·ha-1 for the first year and from 32.1 to 39.7 t·ha-1 for the second season. For the seed clove size study, yields varied from 18.7 to 27.3 t·ha-1 for the first year and from 16.3 to 32.2 t·ha-1 for the second season. Yields and leaf area index (LAI) were directly related to planting density and clove size. Highest yields were attained with maximum studied densities in both seasons. However highest profitability was attained with planting densities of 420,000 plants/ha for the first year, as calculated from the regression equation and 300,000 plants/ha for the second year as there was no statistical difference (P > 0.05) with the two subsequent population treatments and the former has lower costs than the others. The biggest diameters of bulb were always attained with the lowest population densities. In regard to seed size, the highest yield was achieved with 7.5 g/clove for the first season and 13 g/clove for the second season, which also resulted in biggest bulb diameters and therefore in more valuable commercial classes. In accordance with the regression analysis, highest profits were obtained with clove sizes 3.6 to 6.5 g/clove, which yielded from 24 to 27 t·ha-1 for the first season and from 7 to 10 g/clove for the second season, for yields from 29 to 31 t·ha-1. In general, the largest-sized seeds produced lower profits than medium-sized seeds, even though yields were significantly higher. The best planting method for garlic, as evaluated in terms of yield, quality and profitability, was associated with good plant distribution in the field and planting the seed with the apex upwards, characteristics obtained in the hand-planted treatment.
Carrie H. Wohleb and Timothy D. Waters
An onion (Allium cepa) cultivar trial is conducted in the Columbia Basin of Washington every year. The trial helps onion growers, packers, processors, and seed companies compare cultivars and identify those most suited to their operations. This report evaluates 54 onion cultivars that were in the trials 2 years or more from 2012 to 2014. Marketable yields of cultivars averaged 764 to 1314 cwt/acre. ‘TTA-747’, ‘Scout’, ‘SV6672NW’, ‘Montero’, ‘XP07716000’, and ‘SV4058NV’ had the highest yields. All cultivars produced more jumbo-sized (3 to 4 inches) bulbs compared with any other size category, but those with the largest percentages of jumbo bulbs were Utrero, Gunnison, and Sedona. ‘Scorpion’, ‘Ruby Ring’, and ‘Purple Haze’ had the largest percentages of medium (2.25 to 3 inches) bulbs, and ‘Montero’ and ‘Ovation’ had the largest combined percentages of jumbo and colossal (>4 inches) bulbs. Cultivar differences were evident in the 2012 and 2014 trials when many of the onions flowered (bolted). Cultivars averaged 0.0 to 15.5 bolted onions per plot when 2012 and 2014 results were combined. ‘Trekker’, ‘Highlander’, ‘Trailblazer’, ‘Ruby Ring’, ‘NUN8003ON’, and ‘Milestone’ had the fewest bolted onions. Cultivar differences were also apparent when several aspects of bulb quality were evaluated after 4 months in storage. ‘Utrero’, ‘Trekker’, ‘NUN7202ON’, and ‘Tamara’ had the most uniformly shaped bulbs. Bulbs of ‘Crockett’, ‘Legend’, and ‘Utrero’ had the most complete skins. ‘Crockett’, ‘Talon’, ‘Utrero’, ‘Legend’, ‘Gunnison’, and ‘Tamara’ had the firmest bulbs. Only 14 of 54 cultivars averaged more than 74% functionally single-centered bulbs. ‘NUN7202ON’, ‘Arcero’, ‘Joaquin’, and ‘Utrero’ had the largest percentages of bulbs with single centers or small multiple centers. There were more rots caused by bacteria (Enterobacter sp.) in bulbs produced in the 2014 trial than in 2012 and 2013, probably due to a high incidence of internal dry scale in 2014. Incidence of bacterial rot in cultivars was not significantly different in 2014, but there were some cultivar differences in 2012 and 2013. Incidence of fungal neck rot (caused by Botrytis sp.) in these trials was low and there were no significant cultivar differences. The results of these trials demonstrate that many new and advanced experimental cultivars have attributes that could make them a good choice for onion growers in the Columbia Basin.
Camille E. Esmel, Bielinski M. Santos, Eric H. Simonne, Jack E. Rechcigl and Joseph W. Noling
/acre of preplant S in comparison with the nontreated control. Early fruit weight of extralarge and all marketable grades increased by 1.5 and 1.7 tons/acre, respectively, with the application of 25 lb/acre of S ( Fig. 1 ). There were no early fruit weight
Erik B. G. Feibert, Clint C. Shock and Monty Saunders
Onions were grown with different soil water potentials as irrigation criteria to determine the soil water potential at which optimum onion yield and quality occurs. Furrow irrigation treatments in 1992 and 1993 consisted of six soil water potential thresholds (-12.5 to -100 kPa). Soil water potential in the first foot of soil was measured by granular matrix sensors (Watermark Model 200SS, Irrometer Co., Riverside, CA) that had been previously calibrated to tensiometers on the same silt loam series. Both years, yield and market grade based on bulb size (more jumbo and colossal onions) increased with wetter treatments. In 1993, a relatively cool year, onion grade peaked at -37.5 kPa due to a significant increase in rot during storage following the wetter treatments. These results suggest the importance of using moisture criteria to schedule irrigations for onions.
Dale E. Marshall and Roger C. Brook
Green bell pepper is a popular vegetable in the United States. Michigan is the 5th-leading production area, producing 480,000 cwt of green bell peppers in 1994. The tender skin of the green bell pepper covers a crisp, fragile flesh that is easily bruised, cracked, or crushed. During commercial harvest and postharvest handling operations, bell peppers undergo several transfers, each of which has the potential for causing mechanical injury to the pepper fruit. These mechanical injuries include abrasions, cuts, punctures, and bruises. Mechanical injuries and bruises are defects that affect the market grade of the peppers, and may reduce pepper quality and subsequent shipping life. The impacts occurring in a pepper field and on a Michigan packing line were measured using an Instrumented Sphere. Field tests attempted to duplicate how pickers harvest bell peppers into 5-gal pails and empty them into empty wooden tote boxes. Other tests were on an entire packing line. Most bruising on packing lines occurred at the transfers between different pieces of equipment when the peppers fell or were propelled from conveyors onto uncushioned metal plates or rollers. Several transfer points were identified as areas where much of the mechanical damage occurred and improvements were suggested to the packer. Bell peppers were found to bruise on their shoulders; therefore, shoulder bruises may be used as an indicator of injury. The major problems with packing lines were excessive height differences between line components, lack of control of rolling velocity, and lack of cushioning on hard surfaces.
Steven P. Obst, Charles R. Hall and Michael A. Arnold
Arizona ash (Fraxinus velutina Torr.) seedlings were grown in 0.21-L plastic liner containers, half treated with 100 g Cu(OH)2/L latex carrier (formulated as Spin Out), and half nontreated. Seedlings were sequentially transplanted to larger containers, from liners to 2.5-L black plastic containers then to 11.8-L containers resulting in a 2 × 2 × 2 factorial combination of container sizes and Cu-treatments (eight combinations with 30 replicates/treatment). Nursery conditions and production procedures were determined from regional nurseries using a modified Delphi technique. Growth responses (height, caliper, market grade) and costs of production were determined for each treatment combination through marketable size in 11.8-L containers. Significant interactions (P ≤ 0.05) among liner and 2.5-L container treatments occurred for end of season trunk diameter and market ratings. Those seedlings grown in both Cu-treated liners and 2.5-L containers tended to have larger calipers and market ratings than other treatment combinations. Growth increases were not realized when containers were treated at a single stage. Copper-treated containers resulted in a 17-second labor savings per container at transplant from 2.5- to 11.8-L containers. Labor requirements were not significantly (P ≤ 0.05) different among treatments at transplant from 0.21- to 2.5-L containers.