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Kevin A. Lombard, Emmanuel Geoffriau and Ellen B. Peffley

, Lubbock, TX 79409. We acknowledge the support of the TTU Institute for Biotechnology Core Facility. We thank Rio Colorado Seeds Co. (now SunSeeds) for providing onion bulbs. Mention of brands and products does not imply endorsement of the product by Texas

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Jongtae Lee, Jinseong Moon, Heedae Kim, Injong Ha and Sangdae Lee

Onion ( Allium cepa L.) is one of the most important vegetable crops grown worldwide with 57.9 million tons produced annually ( USDA, 2005 ). Onion production has been increasing in Korea owing to enhanced awareness of onion's health benefits

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Clinton C. Shock, Erik B.G. Feibert and Lamont D. Saunders

Six soil water potential irrigation criteria (–12.5 to –100 kPa) were examined to determine levels for maximum onion yield and quality. Soil water potential at 0.2-m depth was measured by tensiometers and granular matrix sensors (Watermark Model 20055, Irrometer Co., Riverside, Calif.). Onions are highly sensitive to small soil water deficits. The crop needs frequent irrigations to maintain small negative soil water potentials for maximum yields. In each of 3 years, yield and bulb size increased with wetter treatments. In 1994, a relatively warm year, onion yield and bulb size were maximized at –12.5 kPa. In 1993, a relatively cool year, onion marketable yield peaked at –37.5 kPa due to a significant increase in rot during storage following the wetter treatments.

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M.R. McDonald, T. Lewis and I. Goldman

Onion lines were evaluated for resistance to Allium white rot (Sclerotium cepivorum Berk.) and onion maggot [Delia antigua (Meig.)] in field plots established on organic soil in the Bradford Marsh, Ontario. White rote valuations were conducted on 20 lines in 1992–1994, with follow-up laboratory trials in 1995. Onion maggot screening was conducted on these same lines in 1993 and 1994. Plots were arranged in a randomized complete-block design with four replications per line. Significant differences in susceptibility to white rot were found in 1992 and 1993, while differences in onion maggot resistance were identified in 1993 and 1994. Commercial cultivars Norstar and Fortress had relatively low levels of onion maggot damage and Fortress demonstrated some tolerance to white rot. Other lines with low levels of white rot infection were 1292-91, 1564-91, 124-93, 116-93, and 117-93, from the breeding program at the Univ. of Wisconsin. Line 1292-91 also had low levels of onion maggot damage. The horticultural characteristics of the onion lines will be discussed.

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Carrie H. Wohleb and Timothy D. Waters

Washington’s onion growers produce ≈20% of the dry bulb onion crop in the United States each year [U.S. Department of Agriculture (USDA), 2014a]. Most of these are summer storage onions planted in the spring and harvested in the late summer and fall

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Troy A. Larsen* and Christopher S. Cramer

New Mexico onion production will begin using mechanical harvesters in the near future in order to stay competitive in today's market. Past onion breeding objectives have focused on improving onions for hand harvesting instead of mechanical harvesting. Our breeding program is starting to evaluate germplasm for bulb firmness. The objectives of this study were to evaluate hybrid lines for their bulb firmness, to compare two methods of measuring bulb firmness, and to compare bulb firmness using two different production schemes. Bulb firmness of spring-transplanted and spring-seeded intermediate-day hybrid breeding lines was measured using a digital FFF-series durometer and a subjective rating of firmness achieved by squeezing bulbs. Bulbs were rated on a scale of 1 (soft) to 9 (hard). In general, these hybrid lines produced very firm to hard onions whether the lines were transplanted or direct-seeded. Bulb firmness of these lines measured with the durometer was greater when the lines were direct-seeded (74.9) than when transplanted (73.5). Conversely, when firmness was measured with our subjective rating, transplanted onions exhibited slightly greater firmness (8.9) than direct-seeded onions (8.8). For both transplanted and direct-seeded onions, durometer readings were weakly correlated in a positive fashion with our subjective rating. In general, durometer readings gave a greater spread in firmness measurements with a range of 69.6 to 77.8 in firmness values. Subjective ratings of bulb firmness ranged from 8.5 to 9.0. Depending on the firmness of evaluated breeding lines, our subjective rating system should be adjusted to better distinguish firmness differences between bulbs.

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Maria A. Macias-Leon and Daniel I. Leskovar

Onion ( Allium cepa ) is an important horticultural crop with a worldwide production of 88,475,089 tons, with China, India, the United States, Egypt, and Iran as the top five producers ( FAOSTAT, 2013 ). In 2013, U.S. onion production was 3

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George E. Boyhan, Ray J. Hicks, Reid L. Torrance, Cliff M. Riner and C. Randell Hill

Onions are an important crop grown on 15,000 acres in southeastern Georgia with over a $125 million value ( Boatright and McKissick, 2006 ). Mild short-day onions known as Vidalia onions are the number one vegetable crop in the state by crop value

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Mohsen Mohseni-Moghadam, Christopher S. Cramer, Robert L. Steiner and Rebecca Creamer

Since 2001, IYSV has been confirmed in all onion-producing states in the western United States, including Arizona, California, Colorado, Idaho, New Mexico, Nevada, Oregon, Utah, and Washington ( Creamer et al., 2004 ; Crowe and Pappu, 2005 ; du

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Giovanni Piccinni, Jonghan Ko, Thomas Marek and Daniel I. Leskovar

specific to multiple phenological stages for important vegetable crops such as onion and spinach. Materials and Methods Lysimeter facility. The lysimeter facility at the Texas AgriLife Research Center in Uvalde, TX (long. 29°13′ N, lat. 99°45′ W; elevation