Bulb Development in Onion (Allium cepa L.) I. Effects of Plant Density and Sowing Date in Field Conditions

1986 ◽  
Vol 58 (2) ◽  
pp. 187-195 ◽  
Author(s):  
M. F. MONDAL ◽  
J. L. BREWSTER ◽  
G. E. L. MORRIS ◽  
HEATHER A. BUTLER
Keyword(s):  
Allium Cepa ◽  
Plant Density ◽  
Sowing Date ◽  
Field Conditions ◽  
Allium Cepa L

scholarly journals Effects of plant density and cultivar on yield responses in onions (Allium cepa L.) grown from seeds

2013 ◽  
Vol 50 (1-2) ◽  
pp. 221-229
Author(s):  
Jan Rumpel ◽  
Kazimierz Felczyński
Keyword(s):  
Allium Cepa ◽  
Field Experiments ◽  
Plant Density ◽  
Leaf Fall ◽  
Marketable Yield ◽  
Onion Bulbs ◽  
Allium Cepa L ◽  
Yield Responses ◽  
Bulb Yield ◽  
Size Grading

Two field experiments were conducted to study the effect of plant density on yield, size grading and maturity of onion bulbs grown from seeds. In the first experiment carried out during 1991-1993, three onion cultivars (Hysam F<sub>1</sub> , Mercato F<sub>1</sub> and Sochaczewska) were sown for intended densities of 20, 40, 60, 80,100 and 140 plants m<sup>-2</sup>, whereas in the second one, in 1996, six onion cultivars (Spirit F<sub>1</sub>, Summit F<sub>1</sub>, Hyduro F<sub>1</sub>, Armstrong F<sub>1</sub>, Renate F<sub>1</sub> and Robusta) were sown for intended densities of 40, 60 and 80 plants m<sup>-2</sup>. The onions were grown on beds, 1,35 m wide, in 4 rows per bed (27+27+27+54 cm). Marketable yield increased with plant density, and depending on year was highest at 80 or 100 plants m<sup>-2</sup>. The average marketable yield of the 1991-1993 experiment increased from 20.5 t·ha<sup>-1</sup> at 20 plants m<sup>-2</sup> to 32.8 t·ha<sup>-1</sup> at 80 plants m<sup>-2</sup>, whereas that of the 1996 experiment increased from 48,9 t-ha<sup>-1</sup> at 40 plants m-2 to 59.0 t·ha<sup>-1</sup> at 80 plants m<sup>-2</sup>, respectively. Yield of large bulbs decreased with density and was highest at 20-40 plants m<sup>-2</sup>, oposite to the yield of small bulbs, which was highest at the highest density of 140 plants·m<sup>-2</sup>. The medium bulb yield increased with density, at the some way as compared the total marketable yield. No greater effect of cultivar on bulb size grades was found and the existing differences were proportional to the total marketable yield . Plant density hastened maturity of onions, and at density of 140 plants m<sup>-2</sup> the leaf fall-over occurred 9-10 days earlier as compared at density of 20 plants m<sup>-2</sup>. The cultiwars used. can be placed in the following order of decreasing productivity: 1 . Mercato F<sub>1</sub>, 2. Hysam F<sub>1</sub> and 3. Sochaczewska, - in the first expeiiment (1991-93) and 1. Annstrong F<sub>1</sub>, 2. Spirit F<sub>1</sub>, 3. Robusta, 4. Renate F<sub>1</sub>, 5. Hyduro F<sub>1</sub> and 6. Summit F<sub>1</sub> - in the second experiment (1996), respectively.

Bacteria occurring in onion (Allium cepa L.) foliage in Puerto Rico.

1969 ◽  
pp. 199-219
Author(s):  
Juan Calle-Bellido ◽  
Lydia I. Rivera-Vargas ◽  
Myrna Alameda ◽  
Irma Cabrera
Keyword(s):  
Puerto Rico ◽  
Pseudomonas Syringae ◽  
Allium Cepa ◽  
Leaf Tissue ◽  
Field Conditions ◽  
Bacterial Strains ◽  
Burkholderia Glumae ◽  
Pathogenic Potential ◽  
Allium Cepa L ◽  
Leaf Tissues

Bacteria associated with foliar symptoms of onion (Allium cepa L.) were examined in the southern region of Puerto Rico from January through April 2004. Different symptoms were observed in onion foliage of cultivars 'Mercedes' and 'Excalibur' at Juana Díaz and Santa Isabel, Puerto Rico. Ellipsoidal sunken lesions with soft rot and disruption of tissue were the most common symptoms observed in onion foliage in field conditions. From a total of 39 bacterial strains isolated from diverse symptoms in onion foliage, 38% were isolated from soft rotting lesions. Ninety-two percent of the bacteria isolated from onion foliage was Gram negative. Pantoea spp. with 25%, was the most frequently isolated genus, followed by Pasteurella spp. and Serratia rubidae with 10% each. Fifty- six percent of the strains held plant pathogenic potential; these strains belong to the genera Acidovorax sp., Burkholderia sp., Clavibacter sp., Curtobacterium sp., Enterobacter sp., Pantoea spp., Pseudomonas spp., and Xanthomonas spp. Pathogenicity tests showed that seven out of eight tested bacterial strains evaluated under field conditions caused symptoms in onion foliage for both cultivars. Acidovorax avenae subsp. citrulli, Burkholderia glumae, Pantoea agglomerans, P. dispersa, Pseudomonas sp., Xanthomonas sp., and Xanthomonas-Wke sp. were pathogenic to leaf tissues. Clavibacter michiganensis was not pathogenic to leaf tissues. Other bacteria identified as associated with onion leaf tissue were Curtobacterium flaccumfaciens, Cytophaga sp., Enterobacter cloacae, Flavimonas oryzihabitans, Mannheimia haemolytica, Pantoea stewartii, Pasteurella anatis, P. bettyae, P. langaaensis, Photobacterium damselae, Pseudomonas syringae pv. aptata, Rhizobium radiobacter, Serratia rubidae, Sphingobacterium spiritivorum, Sphingomonas sanguinis, and an unknown strain. This paper is the first survey of bacteria associated with onion foliage in Puerto Rico. The role of non- phytopathogenic bacteria associated with the life cycle of onion under field conditions remains unknown.

scholarly journals Bacteria occurring in onion (Allium cepa L.) foliage in Puerto Rico.

1969 ◽  
Vol 96 (3-4) ◽  
pp. 199-219 ◽  
Author(s):  
Juan Calle-Bellido ◽  
Lydia I. Rivera-Vargas ◽  
Myrna Alameda ◽  
Irma Cabrera
Keyword(s):  
Puerto Rico ◽  
Pseudomonas Syringae ◽  
Allium Cepa ◽  
Leaf Tissue ◽  
Field Conditions ◽  
Bacterial Strains ◽  
Burkholderia Glumae ◽  
Pathogenic Potential ◽  
Allium Cepa L ◽  
Leaf Tissues

Bacteria associated with foliar symptoms of onion (Allium cepa L.) were examined in the southern region of Puerto Rico from January through April 2004. Different symptoms were observed in onion foliage of cultivars 'Mercedes' and 'Excalibur' at Juana Díaz and Santa Isabel, Puerto Rico. Ellipsoidal sunken lesions with soft rot and disruption of tissue were the most common symptoms observed in onion foliage in field conditions. From a total of 39 bacterial strains isolated from diverse symptoms in onion foliage, 38% were isolated from soft rotting lesions. Ninety-two percent of the bacteria isolated from onion foliage was Gram negative. Pantoea spp. with 25%, was the most frequently isolated genus, followed by Pasteurella spp. and Serratia rubidae with 10% each. Fifty- six percent of the strains held plant pathogenic potential; these strains belong to the genera Acidovorax sp., Burkholderia sp., Clavibacter sp., Curtobacterium sp., Enterobacter sp., Pantoea spp., Pseudomonas spp., and Xanthomonas spp. Pathogenicity tests showed that seven out of eight tested bacterial strains evaluated under field conditions caused symptoms in onion foliage for both cultivars. Acidovorax avenae subsp. citrulli, Burkholderia glumae, Pantoea agglomerans, P. dispersa, Pseudomonas sp., Xanthomonas sp., and Xanthomonas-like sp. were pathogenic to leaf tissues. Clavibacter michiganensis was not pathogenic to leaf tissues. Other bacteria identified as associated with onion leaf tissue were Curtobacterium flaccumfaciens, Cytophaga sp., Enterobacter cloacae, Flavimonas oryzihabitans, Mannheimia haemolytica, Pantoea stewartii, Pasteurella anatis, P. bettyae, P. langaaensis, Photobacterium damselae, Pseudomonas syringae pv. aptata, Rhizobium radiobacter, Serratia rubidae, Sphingobacterium spiritivorum, Sphingomonas sanguinis, and an unknown strain. This paper is the first survey of bacteria associated with onion foliage in Puerto Rico. The role of non- phytopathogenic bacteria associated with the life cycle of onion under field conditions remains unknown.

Effects of transplanting time and plant density on yield, quality and antioxidant content of onion (Allium cepa L.) in southern Italy

2014 ◽  
Vol 166 ◽  
pp. 111-120 ◽  
Author(s):  
Gianluca Caruso ◽  
Stefano Conti ◽  
Gerardo Villari ◽  
Carlo Borrelli ◽  
Giuseppe Melchionna ◽  
...  
Keyword(s):  
Allium Cepa ◽  
Southern Italy ◽  
Plant Density ◽  
Antioxidant Content ◽  
Allium Cepa L ◽  
Yield Quality
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