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George E. Boyhan, David B. Langston, Albert C. Purvis, and C. Randell Hill

Five different statistical methods were used to estimate optimum plot size and three different methods were used to estimate optimum number of replications with short-day onions (Allium cepa L.) for yield, seedstem formation (bolting), purple blotch and/or Stemphylium (PB/S), botrytis leaf blight (BLB), and bulb doubling with a basic plot size unit of 1.5 × 1.8 m (length × width). Methods included Bartlett's test for homogeneity of variance, computed lsd values, maximum curvature of coefficient of variation plotted against plot size, Hatheway's method for a true mean difference, and Cochran and Cox's method for detecting a percent mean difference. Bartlett's chi-square was better at determining optimum plot size with transformed count and percent data compared with yield data in these experiments. Optimum plot size for yield of five basic units (7.5 m length) and four replications is indicated using computed lsd values where the lsd is <5% of the average for that plot size, which was the case in both years of this study. Based on all the methods used for yield, a plot size of four to five basic units and three to five replications is appropriate. For seedstems using computed lsd values, an optimum plot size of four basic units (6 m length) and two replications is indicated. For PB/S two basic units (3 m length) plot size with four replications is indicated by computed lsd values. For BLB a plot size of four basic units (6 m length) and three replications is optimum based on computed lsd values. Optimum plot size and number of replications for estimating bulb doubling was four basic units (6 m length) and two replications with `Southern Belle', a cultivar with a high incidence of doubling using computed lsd values. With `Sweet Vidalia', a cultivar with low incidence of bulb doubling, a plot size of four basic units (6 m length) and five replications is recommended by computed lsd values. Visualizing maximum curvature between coefficient of variation and plot size suggests plot sizes of seven to eight basic units (10.5 to 12 m length) for yield, 10 basic units (15 m length) for seedstems, five basic units (7.5 m length) for PB/S and BLB, five basic units (7.5 m length) for `Southern Belle' doubling, and 10 basic units (15 m length) for `Sweet Vidalia' doubling. A number of plot size-replication combinations were optimum for the parameters tested with Hatheway's and Cochran and Cox's methods. Cochran and Cox's method generally indicated a smaller plot size and number of replications compared to Hatheway's method regardless of the parameter under consideration. Overall, both Hatheway's method and computed lsd values appear to give reasonable results regardless of data (i.e., yield, seedstems, diseases etc.) Finally, it should be noted that the size of the initial basic unit will have a strong influence on the appropriate plot size.

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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.

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K.H.S. Peiris, G.G. Dull, R.G. Leffler, and S.J. Kays

Spatial variation in soluble solids content (SSC) of fruits of apple (Malus ×domestica Borkh. cv. Red Delicious), cantaloupe (Cucumis melo L. Cantaloupensis group), grapefruit (Citrus paradisi Macf. cv. Indian River Ruby Red), honeydew melon (Cucumis melo L. Inodorus group), mango (Mangifera indica L. cv. Hayden), orange (Citrus sinensis L. Osbeck. cv. Valencia), peach (Prunus persica L. Batsch. cv. Windblow), pineapple (Ananas comosus L. Merr. cv. Kew) and tomato (Lycopersicon esculentum Mill.), and of bulbs of onion (Allium cepa L. Cepa group) and in dry-matter content (DMC) of potato (Solanum tuberosum L. cv. Russet Burbank) tubers was measured along three directional orientations (i.e., proximal to distal, circumferentially midway along the proximal to distal axis, and radially from the center of the interior to the outer surface). The pattern and magnitude of constituent variation depended on the type of product and the direction of measurement. Radial and proximal to distal variation was greater than circumferential variation in all the products tested. Honeydew had the highest radial variation with a SSC difference of 6.0 % and a cv of 22.8%, while tomato displayed lower radial variation with a cv of 1.0%. Pineapple had a proximal to distal SSC difference of 4.6% with a cv of 13.8%, while the difference in tomato was 0.6% with a cv of 5.1%. Circumferential variation of SSC in all products tested was <2% with cv ranging from 1.1% to 3.8%. The results confirm that considerable constituent variability exists within individual fruit and vegetable organs. This variability may affect the accuracy of calibration equations and their prediction capability. Therefore, within-unit constituent variability should be meticulously assessed when an NIR spectrometric method is being developed for the nondestructive quality evaluation and sorting of a product.

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Michael J. Havey and Christopher von Kohn

Hybrid onion ( Allium cepa L.) cultivars are widely grown around the world due in part to hybrid vigor and greater uniformity. Because onion has perfect flowers, production of hybrid seed is based on systems of CMS. For the most widely used CMS in

Open access

Michael J. Havey and Sunggil Kim

Hybrid-onion ( Allium cepa ) seed is produced using sources of CMS. The first source of onion CMS was described by Jones and Clarke (1943 ), and male sterility is conditioned by the interaction of the male-sterile (S) cytoplasm with the

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Anil Khar, Jernej Jakse, and Michael J. Havey

. Hered. 57 55 57 El-Shafie, M.W. Davis, G.N. 1967 Inheritance of bulb color in the onion ( Allium cepa L.) Hilgardia 9 607 622 Fossen, T. Andersen, O.M. Ovstedal, D

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Marijana Jakše, Pablo Hirschegger, Borut Bohanec, and Michael J. Havey

cepa L.) breeding materials Plant Sci. 167 1055 1066 Alan, A.R. Lim, W. Mutschler, M.A. Earle, E.D. 2007 Complementary strategies for ploidy manipulations in gynogenic onion ( Allium cepa L

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Jiffinvir Khosa, Robyn Lee, Srishti Joshi, Martin Shaw, John McCallum, and Richard Macknight

Onion and shallot ( Allium cepa L.) are cultivated in a wide range of environments, from hot equatorial regions to high latitudes. Although onion has great cultural and economic value, experimental studies involving genetics and agronomy are quite

Open access

Michael J. Havey

The color of onion ( Allium cepa ) bulbs is one of the most important consumer traits, and bulb colors can be white, yellow, red, or chartreuse ( El-Shafie and Davis, 1967 ). White bulbs are conditioned by a dominant allele at the inhibitor ( I

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Steven Raines, Cynthia Henson, and Michael J. Havey

. Kosaka, S. Shiomi, N. 2004 Effect of temperature on soluble invertase activity, and glucose, fructose and sucrose status of onion bulbs ( Allium cepa ) in store Intl. J. Food Sci. Nutr. 55 325 331 Benkeblia, N