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.
Thomas W. Walters, Leroy A. Ellerbrock, Jan J. van der Heide, James W. Lorbeer, and David P. LoParco
Charles Macharia and Ellen B. Peffley
The genus Amaranthus contains many species which are common weeds found on the Texas high plains. In a field experiment plant height and numbers of plants of Amaranthus varied when grown with different Allium genotypes: Allium fistulosum var. `Heshiko' and an interspecific F1 hybrid 81215 (Heshiko × A. cepa cv. `New Mexico Yellow Grano'). The genotypes that showed no allelopathic effect were A. cepa cv `New Mexico Yellow Grano', A. fistulosum var. `Ishikura', and their F1 hybrid 8273. On the basis of these observations experiments have been done to quantify the degree of suppression. A randomized complete block design was used under greenhouse conditions in order to measure growth characters of Amaranthus.
James R. McFerson, Thomas W. Walters, and Charles J. Eckenrode
Nearly 350 germplasm accessions representing 25 Allium species were evaluated for damage by onion maggot (OM) [Delia antiqua (Meigen)] in field experiments in 1989. In 1990, 188 additional accessions and breeding lines were evaluated, and 36 entries from the 1989 evaluation were re-evaluated. In both years, there were no significant differences in OM damage to seedlings among accessions within the species tested. However, differences among species were highly significant. Allium cepa L. (bulb onion) seedlings had consistently high OM damage. Species with significantly less seedling damage than A. cepa included: A. altaicum Pall., A. angulosum L., A. galanthum Kar. & Kir., A. pskemense B. Fedtsch., A. scorodoprasum L., A. ampeloprasum L. (leek), A. fistulosum L. (bunching onion), A. schoenoprasum L. (chive), and A. tuberosum Rottl. ex Spr. (garlic chive). Some species sustaining minimal damage as seedlings were nonetheless heavily damaged as mature plants by a later generation of OM. Allium cepa cultivars that were well-adapted to local conditions were heavily damaged as seedlings, but their bulbs were less damaged than those of poorly adapted A. cepa germplasm. Allium ampeloprasum seedlings and mature plants sustained low injury throughout both growing seasons.
Gayle M. Volk, Adam D. Henk, and Christopher M. Richards
Garlic (Allium sativum L.) has been clonally propagated for thousands of years because it does not produce seed under standard cultivation conditions. A single garlic accession frequently displays a high degree of phenotypic plasticity that is likely to be dependent upon soil type, moisture, latitude, altitude, and cultural practices. The diversity observed by collectors has occasionally led to the renaming of varieties as they are exchanged among growers and gardeners. As a result, there are numerous garlic varieties available both commercially and within the USDA National Plant Germplasm System (NPGS) that may be identical genotypically, yet have unique cultivar names. To address this possibility, we performed amplified fragment-length polymorphism (AFLP) analysis on a comprehensive selection of 211 Allium sativum and Allium longicuspis accessions from NPGS and commercial sources. We used several statistical approaches to evaluate how these clonal lineages are genetically differentiated and how these patterns of differentiation correspond to recognized phenotypic classifications. These data suggest that while there are extensive duplications within the surveyed accessions, parsimony and distance based analyses reveal substantial diversity that is largely consistent with major phenotypic classes.
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 (causal agent Botrytis squamosa Walker). In greenhouse evaluations, plants were sprayed with laboratory-grown mycelial fragment inoculum and were incubated at 20C in a chamber with an atomizing fogger. For field inoculations, a portable fog system with windbreaks was erected around experimental plots, and the plants were sprayed with the inoculum on evenings when windless, temperate (18 to 22C) conditions were forecasted. The most effective mycelial fragment inoculum was <21 days old and had ≈45 to 50 colony-forming units/μl, resulting in an absorbance at 450 nm of 0.2 to 0.3. Rubbing the wax cuticle from leaves was essential to disease development in greenhouse but not in field experiments. Evaluations of eight Allium species, including 55 A. cepa L. accessions, were in agreement with previous studies.
Paul D. Curtis, Gwen B. Curtis, and William B. Miller
Many plants have mechanisms of physical or chemical resistance that protect them from herbivores in their environment. Vertebrates such as meadow voles (Microtus pennsylvanicus) cause significant damage to ornamental plantings and home gardens. Our goal was to identify flowering bulbs that could be used to design more herbivore-resistant home landscapes. Single-choice feeding trials with captive prairie voles (Microtus ochrogaster) were used to assess the relative resistance of 30 bulb varieties to deter rodents from consuming fresh plant material and freeze-dried, powdered bulb mixed with a preferred food (applesauce). Each fresh bulb and dried-bulb/applesauce mix was offered twice to 12 to 15 pairs of adult prairie voles. Bulb varieties that resulted in the lowest mean consumption were assumed to be the most resistant to feeding activity. With fresh bulbs, only tulips (Tulipa spp.) exhibited no resistance to prairie vole feeding. Dried-bulb/applesauce mixes containing hyacinth (Hyacinth spp.), crocus (Crocus spp.), corn leaf iris (Iris bucharica), dutch and dwarf iris (Iris reticulata), onion (Allium spp.), and squill (Scilla siberica) were also readily consumed, and thus, these bulbs could be damaged at sites with high rodent activity. Daffodil (Narcissus spp.), painted arum (Arum italicum), camass (Camassia leichtlinii), glory-of-the-snow (Chinodoxa forbesii), autumn crocus (Colchicum spp.), crown imperial (Fritillaria imperialis), persian fritillaria (Fritillaria persica), snowdrop (Galanthus nivalis), and grape hyacinth (Muscari armeniacum) bulbs were resistant to prairie vole feeding in both forms (fresh bulbs and dried-bulb/applesauce mixes). Consequently, all of the specialty flower bulbs tested, except tulip, exhibited some resistance to prairie vole feeding in their fresh form, and could be suitable for designing herbivore-resistant landscapes.
Anil Khar, Jernej Jakse, and Michael J. Havey
, T. Andersen, O.M. Ovstedal, D.O. Pedersen, A.T. Raknes, A. 1996 Characteristic anthocyanin pattern from onions and other Allium spp J. Food Sci. 61 703 706 10.1111/j.1365-2621.1996.tb12185.x
Michael J. Havey and Farhad Ghavami
marker based analysis of genetic diversity in short day tropical Indian onion and cross amplification in related Allium spp Genet. Resources Crop Evol. 58 741 752 10.1007/s10722-010-9616-y Magruder, R. Webster, R. Jones, H.A. Randall, T. Snyder, G
Augusto Ramírez-Godoy, María del Pilar Vera-Hoyos, Natalia Jiménez-Beltrán, and Hermann Restrepo-Díaz
Diaphorina citri (Hemiptera:Psyllidae) in Persian lime under field conditions Intl. J. Trop. Insect Sci. 32 1 39 44 Mann, R.S. Rouseff, R.L. Smoot, J.M. Castle, W.S. Stelinski, L.L. 2011 Sulfur volatiles from Allium spp . affect Asian citrus psyllid
Neel Kamal and Christopher S. Cramer
onions to thrips (Thysanoptera, Thripidae) J. Econ. Entomol. 72 614 615 Cramer, C.S. Bag, S. Schwartz, H.F. Pappu, H.R. 2011 Susceptibility of onion relatives ( Allium spp.) to Iris yellow spot virus Plant Dis. 95 10 1319 Cramer, C.S. Kamal, N. Singh, N