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Christopher S. Cramer, Neel Kamal, and Narinder Singh

found on either leaves or seedstalks reduce leaf photosynthetic area. This reduction decreases onion bulb size and yield of larger bulb classes or causes premature seedstalk lodging that in turn reduces seed yield ( du Toit et al., 2004b ; Gent et al

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Joseph J. King and Michael J. Havey

The bulb onion (Allium cepa L.) is a diploid with an very large nuclear genome of 15300 Mbp/1C (107× arabidopsis, 16× tomato, 6× maize). We developed a low-density genetic map with morphological, RAPD, and RFLP markers to examine genome organization and to study QTL controlling phenotypically correlated bulb quality traits. A mapping population of 58 F3 families was derived from a cross of the inbreds Brigham Yellow Globe 15-23 (BYG) × Alisa Craig 43 (AC). These inbreds are distinct in solids, storability, pungency, and bulb shape. Analysis of 580 RAPD primers detected 53 (9%) polymorphisms between BYG and AC, but only 12 (2%) segregated at expected ratios among F3 families. Using probes from onion cDNA libraries and four restriction enzymes, 214 RFLPs were identified between mapping parents. A 112-point map includes 96 RFLPs, 13 RAPDs, a locus controlling complementary red bulb color, and two loci hybridizing with a clone of the enzyme alliinase (EC 4.4.1.4), which produces the flavors characteristic of Allium species. Duplicated loci were detected by ≈25% of RFLP probes and were unlinked, loosely linked (2 to 30 cM), or tightly linked (<2 cM). This frequency of duplication was comparable to species with polyploid ancestors (paleopolyploids) and was higher than that found in most true diploids. However, the distribution of duplicated loci suggests that, in contrast to whole genome duplications typical of paleopolyploids, the contemporary size and structure of the onion genome may be a product of intrachromosomal duplications (cryptopolyploidy) and subsequent structural rearrangements.

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Young-Seok Kwon, Kwang-Soo Cho, Ju-Seong Im, Eung-Ho Lee, and Won-Bae Kim

Onions are a major vegetables in Korea. Short-day onions are grown in more than 95% in southern area of South Korea, and long-day onions are grown above 600-m altitude in the highlands. Onion cultivation in the highland areas has become difficult for farmers to obtain high income but stable production because of higher cost of seed and the intensive labor involved in production. Consequently, onion set culture by inexpensive onion seeds compared with expensive F1 seed has an advantage due to the higher proportion of marketable size bulbs. This study was conducted to find out the suitable sowing time and tray size for onion set culture in the highlands—the earlier the sowing time, the higher the number of onions set. The most appropriate sowing date and 1.6–3.5 g of onion set size was early to middle May, also with the highest distribution percentage. The highest set number (780.8 set/m2) of suitable onion set size (1.6–3.5 g) were harvested from the 288 trays, followed by 770 set from the bed (9 g/m2 of seed sowed), and (7/m2 of seed sowed) in the 406 tray.

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Christopher S. Cramer and Joe N. Corgan

onion that was developed by Dessert Seed Co. in 1964 ( Havey, 2007 ). ‘Early Supreme’ produces very large to jumbo-sized, pungent, flattened globe-shaped bulbs that have very good pink root resistance, intermediate fusarium basal rot resistance {causal

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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.

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David C. Zlesak and Neil O. Anderson

·m −2 ·s −1 at plant level) was used. Data collected. For FC1 and FC2, initial bulb weight and circumference (except for S1-FC1 bulbs because of the assumption bulbs were uniform in size and within the designated commercial size class), days to

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Paul D. Curtis, Gwen B. Curtis, and William B. Miller

Flower bulbs provide an important design and color component in the landscape, and are very popular with the gardening public. They are especially valued for their diversity of flower shapes, vibrant colors, sizes, and flowering periods. They are

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Christopher S. Cramer and Joe N. Corgan

’ is most comparable to ‘NuMex Starlite’ with respect to bolting percentage, pink root, and FBR disease severity and incidence, percentage marketable bulb yield, marketable bulb yield, and average bulb size ( Table 2 ). ‘NuMex Serenade’ has excellent

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Junyang Song

), environmental and climatic factors ( Treder, 2008 ; Xia et al., 2005 ), and foliar applications of biological agents ( De Lucia and Vecchietti, 2012 ; Zheng et al., 2012 ) on the growth of bulbs. Recently, the influence of bulb sizes on cut flower ( Kim and

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Carrie H. Wohleb and Timothy D. Waters

to onion bulb size distribution, and sometimes to total marketable onion yield ( Brewster, 2008 ; Shock et al., 2004 ). A shift to larger bulb size is favored by low plant population and less plant competition. Conversely, higher plant population and