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Usha S. Kallemuchikkal and E.B. Peffley

Total genomic DNA was isolated from study plants and was hybridized with 32P-labeled Allium fistulosum `Ishikura' genomic DNA; Southern blots were performed. Plant materials were Allium cepa `New Mexico Yellow Grano', the Allium fistulosum `Heshiko' and `Ishikura', and their F1 interspecific (Allium fistulosum × Allium cepa) hybrids. Sequences with high identity to the labeled DNA hybridized strongly (i.e., A. fistulosum `Ishikura' hybridized most strongly to itself, next with A. fistulosum `Heshiko'). The least hybridization was observed when A. fistulosum `Ishikura' was hybridized with A. cepa `New Mexico Yellow Grano'. Intensity of the signals observed when DNA of the F1 interspecific hybrids was probed with the `Ishikura' DNA was as expected, with the signals intermediate between those of A. fistulosum to A. fistulosum and A. fistulosum to A. cepa. A second study was performed to identify additional cytological markers in Allium. The 5srDNA and NOR genes from Triticum aestivum onto onion chromosomes using in situ hybridization. Evidence of hybridizations are the presence of fluorescing areas on the chromosomes.

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Ockyung H. Bark, Michael J. Havey, and Joe N. Corgan

The edible Alliums are economically important world-wide. The bulb onion (Allium cepa) is the most widely grown. The Japanese bunching onion (A. fistulosum) has many desirable characters, e.g., resistance to pink root, Thrips, smut, maggot, and Botrytis. Transfer of pink root resistance from A. fistulosum into A. cepa has been attempted for over 60 years. However, sterility of the F1 hybrid is a barrier and there is little evidence of gene introgression during backcrossing to A. cepa. Dr. Corgan has made crosses between A. fistulosum as the seed parent and A. cepa. He backcrossed the F1 hybrids to A. cepa and generated BC2 progenies which showed excellent pink root resistance. RFLPs in the chloroplast genome showed all BC2 progenies had either the normal or sterile cytoplasm of A. cepa. This may be due to not strictly maternal inheritance of the chloroplast DNA or a seed mixture during backcrossing. Other interspecific hybrids and their BC1 progenies had the cytoplasm of A. fistulosum. Nuclear RFLPs show hybrid patterns in the F1 plants. BC1 progenies possess some A. fistulosum markers as evidence of DNA introgression from A. fistulosum into the backcross progenies.

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Nathan C. Phillips, Steven R. Larson, and Daniel T. Drost

habitat of three intermountain Allium species native to Utah, we used the amplified fragment length polymorphism (AFLP) technique in investigating patterns of genetic diversity within and among the study populations. The description of our study offers

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Shigenori Yaguchi, Masanori Atarashi, Masatoshi Iwai, Shin-ichi Masuzaki, Naoki Yamauchi, and Masayoshi Shigyo

Japanese bunching onion ( Allium fistulosum ) is one of the most important vegetable crops in eastern Asia, especially in Japan, Korea, and China ( Inden and Asahira, 1990 ). Allium fistulosum is a perennial plant, grown commercially as an

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I.L. Goldman and B.R Schwartz

In the past twenty years, the presence of blood anticoagulants in plants has been confirmed by a range of clinical and in vitro investigations. The presence of anti-clotting factors in plants presents a unique opportunity for dietary enhancement of circularion and fibrinolysis. Experiments were conducted to assess variability in anticoagulant activity of a range of Allium wild species and cultivated accessions. Anticoagulant activity was determined via a platelet aggregation assay with human plasma. Extracts were prepared from 19 Allium species accessions and 24 cultivated accessions of Allium cepa, including standard inbred lines and open-pollinated popularions. Relative inhibition of platelet aggregation was measured for each accession and inhibition constants (IC50) were calculated. Data from this investigation dcmonstrate large IC50 variability among accessions. Larger IC50 differences (up to 45-fold) were measured among A. cepa accessions than among Allium species accessions (up to 16-fold). Yellow storagc-type A. cepa accessions exhibited the strongest inhibitory activity. Implications of these findings to onion breeding and platelet function will be presented.

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William Randle, Orville Lindstrom, and Daniel Warnock

The onion crop in Georgia is often damaged by suboptimal winter temperatures. Proper acclimation of seedlings is a way of limiting freeze damage. Because photoperiod is among the factors involved in plant acclimation, the effects of photoperiod on the acclimation of short-day Allium cepa seedlings was investigated. A single short-day cultivar, 'Granex 33', was greenhouse grown under an eleven hour photoperiod. After ten weeks of growth, four photoperiod treatments (8, 11, 14, and 24 hrs.) were administered during a two week hardening period at 3* C. Plants were then frozen in an ethylene glycol bath. Degree of acclimation was determined based on regrowth and visual observation. Acclimation of seedlings was completely inhibited by the 24 hour photoperiod. Varying degrees of acclimation were achieved with the other photoperiod treatments.

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Thomas W. Walters, Leroy A. Ellerbrock, Jan J. van der Heide, James W. Lorbeer, and David P. LoParco

Greenhouse and field methods were developed to screen Allium spp. for resistance to Botrytis leaf blight (caused by Botrytis squamosa Walker). In the green-house, plants were sprayed with laboratory-grown inoculum and incubated in a temperature-controlled enclosure containing an atomizing mist system. For field inoculations, a portable misting system with windbreaks was erected, and the plants were sprayed with laboratory-grown inoculum. Greenhouse and field incubation conditions maintained leaf wetness without washing inoculum from the leaves. Botrytis leaf blight symptoms in greenhouse and field evaluations were identical to symptoms in commercial onion fields. A total of 86 selected USDA Allium collection accessions were evaluated using these methods. All A. fistulosum accessions and A. roytei were highly resistant to immune, as were most accessions of A. altaicum, A. galanthum, A. pskemense, and A. oschaninii. Nearly all of the A. vavilovii and A. cepa accessions were susceptible. However, one A. cepa accession (PI 273212 from Poland) developed only superficial lesions, which did not expand to coalesce and blight leaves. This work confirms previous reports of Botrytis leaf blight resistance in Allium spp., and suggests that strong resistance exists with A. cepa.

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Yukihiro Fujime

diameter. Rakkyo, rakkyo in Japanese ( Allium chinense G. Don). Rakkyo is perennial and tillers vigorously. Each shoot forms a small bulb (2 to 5 cm long) at the base. One bulb multiplies into six to nine (large-bulb type) or 10 to 15 (multiple-bulb type

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Philipp W. Simon

Central Asia is the center of origin for many Allium species and a rich genetic source of wild relatives of onion and garlic. For this reason germplasm collections of cultivated Alliums have targeted the acquisition of seed and bulb samples from this region, and several plant expeditions from Asia, Europe, and North America have collected Allium germplasm in Central Asia. Central Asian Allium germplasm has been valuable both as raw materials for scientific research leading to published data, and as starting materials for genetic improvement of the crop. Utilizing this germplasm it has been possible to improve garlic so it can be bred like other seed-propagated crops. Several interspecific crosses have been made between onion and other Central Asian wild relatives and these crosses have yielded useful traits for onion improvement. Allium germplasm from this region has also been important in elucidating the systematics and origins of diversity in onion and garlic. By any of these measures, Central Asian Allium collections have been valuable. Challenges and successes in collecting, maintaining, evaluating, and using these collections remain.

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Juan Carlos Díaz-Pérez, Jesús Bautista, Gunawati Gunawan, Anthony Bateman, and Cliff Martin Riner

Vidalia onions ( Allium cepa L.) are sweet, short-day, low pungency, yellow Granex-type bulbs that are popular in the United States because of their mild flavor ( Boyhan and Torrance, 2002 ). Vidalia onions are exclusively grown in Southeastern