Bulb Diameter Research Articles

Correlations between agronomic characters in garlic

Abstract The objective of this work was to evaluate the phenotypic correlations between agronomic characters of garlic (Allium sativum) and to carry out the path analysis, using commercial bulb yield as the main character. The experiment was conducted under field conditions in two harvests (2018 and 2019) in the municipality of Diamantina, in the state of Minas Gerais, Brazil. A total of 13 garlic genotypes were evaluated, of which 11 were experimental and 2 were commercial cultivars. The experimental design used was randomized complete blocks with four replicates. Characters related to plant biometry and bulb yield were evaluated. The phenotypic correlations and the path analysis of the studied characters were carried out. The phenotypic correlations that showed significant positive effects occurred between commercial bulb yield and plant height, bulb diameter, number of commercial bulbs, mean total bulb mass, mean commercial bulb mass, total bulb yield, and number of bulbils per bulb. However, only number of commercial bulbs and bulb diameter had significant effects (direct and indirect) on commercial bulb yield. Therefore, in genotype genetic breeding programs in the studied region, selection should seek a larger diameter of bulbs and a higher number of commercial bulbs to increase commercial yield.

Onion culture: experimental techniques for carrying out high precision experiments

The cultivation of onion Allium cepa L. is of extreme economic importance globally, and, because of this, research must be constantly updated in order to increase productivity. This study was designed to estimate the optimal plot size, sample size and number of repetitions for experiments evaluating variables in the onion crop. Uniformity tests were carried in the years 2016 and 2017 in the experimental area of the Crop Science Department at Universidade Federal de Santa Maria, Santa Maria (RS), Brazil. Each plant was considered a basic experimental unit. Bulb mass, bulb height, and bulb diameter were measured for each basic experimental unit. The optimal plot size, sample size, and number of repetitions were estimated by the method of maximum curvature of the variation coefficient. For onion culture, the optimal plot size to evaluate the bulb mass, bulb height and bulb diameter is eight, six and six, respectively. The optimal sample size for evaluating the bulb mass of the onion crop is six plants, while for the height and diameter variables the optimal sample size is four plants in the direction of the row considering a semi-amplitude of the confidence interval (D%) equal to 20% of the average. Bulb mass variables require 10 repetitions to assess up to 20 treatments in a randomized block design for the least significant difference of the Tukey’s test, expressed as a percentage of the average of 35%. Bulb height and bulb diameter require just six repetitions for the same assessment.

Effect of PSB and vermicompost on yield and quality of garlic (Allium sativum)

An experiment was conducted at R B S College, Bichpuri, Agra, during winter season of 2019–21 to find out the effect of phosphorus-solubilizing bacteria and vermicompost on yield and quality of garlic. The experiment was laid out in Randomized Block Design having three replications and seven treatments. The treatments were T1 (control), T2 (50% RDF + PSB), T3 (50% RDF + vermicompost), T4 (50% RDF + vermicompost + PSB), T5 (80% RDF + PSB), T6 (80% RDF + vermicompost) and T7 (80% RDF + vermicompost + PSB). The application of 80% RDF + vermicompost + PSB) (T7) recorded significantly maximum plant height (72.4 cm), green leaves/plant, leaf length (60.9 cm), leaf width (1.69 cm), Fresh weight of top (15.60 g), polar diameter of bulbs (5.28 cm), equatorial diameter of bulbs (4.86 cm), neck thickness of bulbs (9.47 mm), highest longest clove (3.62 cm), total bulb yield (155.5 q/ha)dry weight of bulb (19.01 g) and leaves (1.98 g). While, all parameters were recorded minimum in the control.

Effect of organic manure and inorganic fertilizer on growth, yield and quality of garlic (Allium sativum L.)

The experiment entitled “Effect of Organic Manure and Inorganic Fertilizer on Growth, Yield and Quality of Garlic (Allium sativum L.)” was conducted during Rabi season of the year 2021-2022 on Instructional farm of Department of Horticulture, AKS University, Satna (M.P.). The experiment was laid out in Randomized Block Design comprising of 12 treatments viz., T1- Control, T2 - 100% RDF(NPK), T3 - 100% Vermicompost, T4 - 100% FYM, T5 - 100% Poultry manure, T6 - 75%RDF + Poultry manure (10 q/ha), T7 - 50%RDF + Poultry manure (20 q/ha), T8 - 75% RDF + FYM (60 q/ha), T9 - 50%RDF + FYM (120 q/ha), T10 - 75% RDF + Vermicompost (40 q/ha), T11 - 50% RDF + Vermicompost (80 /ha), T12 - 50%Poultry manure (13q/ha ) + FYM (80q/ha) + Vermicompost (53 q/ha), each replicated three times. Treatments were randomly arranged in each replication, divided into twelve plots. The results reveal that the application of 50 % Poultry manure + 50 % FYM + 50 % Vermicompost (T12) gave maximum plant height, highest number of leaves per plant, leaf area per plant, leaf length, leaf width, diameter of bulb, weight of the bulb, number of cloves per bulb, weight of the clove, yield per plot and bulb yield, Specific gravity of bulb, Dry matter content of leaf, Dry matter content of bulb and T.S.S. (OBrix) of garlic.

Performance Evaluation of Onion Varieties at Biyo Awale Cluster in Diredawa Administration

Onion (<i>Allium cepa</i> L.) is an important crop worldwide. It is important in the daily Ethiopian diet. It is widely produced by small farmers and commercial growers throughout the year for local use and export market. No strong study has been conducted to evaluate the suitability of onion cultivation in Biyo Awale district of Diredawa. Hence, the present experiment was conducted to study the performance of improved varieties of onion for their suitability for cultivation in Biyo Awale district of Diredawa. The study was carried out during 2018-2019 cropping season to test the performance of onion varieties. Five high yielding onion varieties were planted in complete randomized block design experiment with three replications including local check at farmer’s field. The quantitative data on bulb yield, plant height, bulb size and number of leaves of onion varieties were collected. Harvesting was done and weighed when all onion varieties reach maturity (90% tops down). The results revealed that the tested onion varieties differ significantly for leaf length, leaf number, neck diameter, bulb diameter, average bulb weight and bulb yield. Among the varieties Bombay red and Melkam produced higher bulb yield (25.56 and 21.13 t ha^-1) and gave 140.68% and 98.96% yield advantage over local check varieties, respectively. Therefore, Bombay Red and Melkam varieties were recommended to the study area and similar agro-ecology.

Determination of Optimal Irrigation Scheduling for Onion (&amp;lt;i&amp;gt;Allium cepa&amp;lt;/i&amp;gt; L.) in Gumara Scheme, North Western Ethiopia

The experiment was performed at Gumara irrigation scheme farm in the 2017/18 and 2019/19 irrigation seasons, with the objective of determining the optimum irrigation schedule based on the available soil moisture depletion levels. The experiment was carried out in RCBD with three replications, randomly assigned to the experimental plots with treatments. Six available soil moisture depletion levels (60, 80, 100, 120, 140, and 160%) were use. The results obtained of two years of research showed that different rates of levels of soil moisture available had a very highly significant effect (P<0.0001) on bulb mass, bulb diameter, marketable yield, and water productivity. The highest marketable bulb yield and water productivity (35222.2 kg ha^-1 and 7.06kg/m³) were recorded at 80% and available soil moisture depletion levels (ASMDL) and also the lowest non-marketable bulb yield (1513.9 kg/ha) was recorded at 80% ASMDL. However, the lowest marketable yield, lowest water productivity and highest non-marketable bulb yield (28722.2 kg ha^-1, 5.29 kg/m³ and 5236.1 kg /ha) was recorded at 160 percent ASMDL Very highly significant (P < 0.0001) plant height and bulb length differences were observed due to the treatments. The highest plant height and bulb length were recorded at 60 per cent AMADL (66.33 cm and 5.62 cm respectively). However, different soil moisture depletion levels showed no significant difference in the stand count of onion. The highest efficiency of water use on onion yield (7.06 kg/m³) was attained at 80 percent ASMDL, whereas the minimum efficiency of water use (5.29 kg/m³) was recorded at 160 per cent ASMDL. Therefore, based on the findings of the current experiment, it is recommended that using 80%ASMDL for furrow irrigation system for onion to be grown in areas around Fogera and similar agroecology as best options to increase yield and water use efficiency for the production of onion.

Introduction of Garlic Cultivation Technology Packages in West Java, Indonesia

Massive import of garlic products has caused a declining interest of Indonesian farmers to plant garlic due to losing competition in clove size and lower selling price. This has discouraged the farmers from applying the innovation of garlic farming technology that caused low garlic productivity in Indonesia (8.7 t/ha). The purpose of this research was to improve the technology package of garlic cultivation at the farmer level. The study was conducted from July to October 2021 in Cianjur Regency, West Java, Indonesia. The technology packages experimental design was randomized block design with nine replications. The technology packages tested were farmer’s technology package, introduced technology package-1, and introduced technology package-2. The components of the technology package tested were cultivar, mulch types, number of cloves per hole, biofertilizer, biopesticide, and chemical fertilizers. The observed variables were plant growth, bulb yield, and input-output of farming. The results showed that the technology package introduction could increase the plant performance, namely the plant height, stem diameter, bulb fresh weight and bulb diameter. The highest R/C ratio was reached by the technology package introduction-1 (1.47). The introduced technology package-1 was more profitable than package-2 as indicated by the MBCR value of 12.46 and 8.83 respectively.

Eficiência no uso de água e qualidade de cebola em cenários climáticos futuros

ABSTRACT Considering that changes in climatic parameters directly interfere in crop yields, this study aimed to evaluate the impact of changes in carbon dioxide concentrations, temperature and soil water availability on production, water-use efficiency and onion (Allium cepa L. cv. IPA 11) quality. Four levels of soil water availability (40, 60, 80 and 100 %) and two concentrations of atmospheric CO2 (770 and 390 ppm) were evaluated in three experiments with different temperature regimes (18-24-30, 22-28-34 and 26-32-38 ºC), in Phytotron growth chambers. The water-use efficiency, bulb diameter and weight, shoot dry weight, pulp frmness, soluble solids content, pH and titratable acidity were also evaluated. The increase in temperature reduces the production, and a higher soil water availability increases the production of IPA 11 onion bulbs. The temperature regime of 18-24-30 ºC and the water availability of 76.72 % provide the best water-use efficiency for the onion crop.

Efficacy of irrigation intervals and chemical weed control on optimizing bulb yield and quality of onion (Allium cepa L.)

Two field experiments were carried out at the village ten, Abu Humus, El-Beheira Governorate, Egypt, during the two successive seasons 2016/2017 and 2017/2018, to evaluate the effect of three types of herbicide and three irrigation intervals on productivity and quality of onion cultivar (Giza Red). The experiments were designed as split plot in randomized complete block design with three replications. Irrigation intervals – (I1) 20 days, (I2) 30 days, and (I3) 40 days – were assigned to the main plots. Herbicides treatments – (H1) Control, (H2) Fluazifop-p, (H3) Oxyfluorfen, and (H4) Clethodium – were distributed randomly in sub-plots. The results revealed that the interaction between herbicide and irrigation intervals had significant effects on productivity and quality of onion (Giza Red) cultivar in both seasons. Maximum onion bulbs yield (14.06 and 14.29 ton/fed) was recorded at (I3 with H3) treatments in first and second seasons, respectively. (I2 with H3) led to increase onion harvest index values. The highest value of carbohydrates percentage and total soluble solids (TSS) obtained at {I3 and H2}. Herbicides residues in dry onions bulbs under all treatments were found well below the maximum residue limit set by World Health Organization (WHO)/Food and Agriculture Organization (FAO) (0.05 mg/kg). In conclusion, the interaction of Oxyfluorfen herbicide and irrigation interval 40 days could be used to improve fresh and dry bulb yield (ton/fed) of onion cultivar, harvest index and water use efficiency (WUE). The treatment of {I3 (40 days) with H2 (Fluazifop-p)} could be used to enhance bulb diameter (cm) after harvest, TSS and the percentage of carbohydrates.

Investigation of the Response of onion (Allium Cepa L.) to continuous deficit irrigation as smart approaches to crop irrigation under Mediterranean conditions

Water is a crucial resource for food production and its scarcity associated with frequent droughts has increased the need for a more efficient use of it along with new irrigation management technologies. This study addressed onion crop responses to continuous deficit irrigation with trigging thresholds of readily available water content. The experiment was conducted on an experimental plot in open field in Morocco. Three water regimes were applied T1 control (100%), T2 (75%) and T3 (50%) of crop evapotranspiration ETc combined with two trigging thresholds (10% and 5%). This is a complete random block device with four repetitions. The measurements concerned the monitoring of vegetative, Eco physiological and yield parameters. The results obtained show that: (i) 100% ETc irrigation at a threshold of 5% of RAW recorded the maximum bulb diameter and weight, thus achieving the best marketable bulb yields. However, in terms of yields, this treatment is not significantly different from the other irrigation regimes with the exception of the irrigated treatment at 50% daily ETc and at a threshold of 10% RAW. The latter recorded the lowest values in terms of production parameters. (ii) For the ecophysiological parameters, significant effects of irrigation dose were observed for proline content, stomatal conductance and leaf temperature, and the effect of the trigging threshold was clearly observed for the moisture content of the leaves. (iii) Water restrictions have minimized the rate of premature run and population density of Thrips tabaci in the onion. (iv) Finally, the best agronomic efficiencies in the use of irrigation water were recorded in treatments with a water restriction of 50%.

Effects of seedling thickness on the production and quality of onion (Allium cepa L.) ‘Santa Rita’ in Arequipa, Peru

Onion crop begins with seedling preparation and finishes with transplanting. In some Peruvian onion-productive areas, it is assumed that seedling thickness is important to have a better yield. Four different seedling thickness of red onion (Allium cepa L.) were evaluated between February and June 2017 in Santa Rita de Siguas, Arequipa, Peru. The seedling thicknesses evaluated were very thin (2.00 mm – 3.49 mm), thin (3.50 mm – 4.99 mm), standard (5.00 mm – 6.49 mm) and thick (6.50 mm – 7.99 mm). The plant density was 340 000 plants ha−1. The experimental design was a randomized complete block with four treatments and five replications. The variables evaluated were plant height (cm), leaf number, stemlike diameter (mm), bulb diameter (mm), total yield (t ha−1), and marketable yield categories (t ha−1). The leaf number, plant height, and stemlike diameter among treatments were significantly different, with higher values in the “standard” and “thick” treatments up to 60 days after transplanting. The harvest was earlier in the “standard” and “thick” treatments. The “very thin” and “thin” treatments needed more days to harvest than the others. The “thin” treatment showed the highest total yield. There were no significant differences between marketable yield categories in all treatments. It was concluded that seedling thickness upon transplanting influences the yield under the conditions in this study.

Variability in yield parameters of onion genotypes in Bundelkhand region of Uttar Pradesh

Of the seventeen onion varieties evaluated for assessment of variability in mean performance, variances, heritability and genetic advance, (L-883 and Bhima Shweta) were most promising genotypes in respect of gross and marketable bulb yield, minimum number of bolters, rotten and multi-centred bulbs, bulb weight, equatorial bulb diameter, total soluble solids, number of leaves per plant and earliness in maturity. High values of genetic and phenotypic for gross and marketable bulb yield, average bulb weight, days to 70% neck fall and plant height indicated more opportunity of selection for these traits. High genetic advance as percentage of mean coupled with high heritability was observed for gross and marketable bulb yield and average bulb weight. Therefore, significant improvement could be expected through selection for these traits.

Response of green garlic to plant density and spraying with algae extract

This experiment was carried out to study the impact of plant density 5, 6, 7 and 8 lines/ ridge (22, 27, 31, 36 plants/m2) and foliar application of Ascophyllum nodosum and Ecklonia maxima extracts at rate of (0, 0.5 and 1 mL/L) and their interaction on plant growth, yield and chemical constituents of green garlic bulbs under new reclaimed soil. The obtained results showed that plant density 5 and 7 lines/ ridge recorded highest values of plant length, bulb diameter, plant fresh weight, nitrogen and crude protein percentage in dry matter of green garlic bulbs. The plant density of 5 lines/ ridge scored the highest values of leaf area, plant dry weight, bulb weight at harvest time and total carbohydrates concentration. In addition, plants cultivated at rate of 8 lines/ ridge gave the highest values of total yield of green garlic and bulbing ratio. The plant densities at rate of 5 and 6 lines/ ridge scored the highest values of bulb diameter and bulb dry matter at harvest time. Foliar application of 1 mL/L A. nodosum extract led to the highest total yield of green garlic, bulb weight at harvest time, bulb diameter, dry matter percentage, nitrogen and crude protein percentage in dry matter of bulbs. On the other hand, plants sprayed with 0.5 mL/L of A. nodosum and E. maxima extracts gave higher total carbohydrates concentration in bulbs than other treatments. Additionally, plants sprayed with 0.5 and 1 mL/L of A. nodosum extract gave higher potassium percentage in bulbs than other foliar application treatments.

Response of growth, yield and quality of small onion (Allium cepa L. var. aggregatum don.) to Tamil Nadu Agricultural University-Water Soluble Fertilizers (TNAU-WSF)

Enhancing the food production for the growing world population has needed application of highly sustainable and efficient inputs to produce more food per unit of land. Hence, Tamil Nadu Agricultural University (TNAU), Coimbatore, Tamil Nadu has produced Water soluble fertilizers (WSF) in its maiden attempt and it is necessary to optimize on different crops. Small onion is one of the most important vegetables in the Indian diet and it has high demand but low productivity. To enhance crop productivity and quality of small onions, the application of TNAU-WSF was taken up. A field experiment was laid out in a Randomized block design (RBD) incorporating 8 treatments comprising of application of RDF at100% NPK as TNAU WSF, soil test based application of 75%, 100%, 125% NPK ha-1 as TNAU-WSF with soil application of sulphur (S) and foliar spray of TNAU Liquid multi micronutrient (LMM) and without S and TNAU LMM and absolute control. Each treatment was replicated thrice with onion (CO 4). Soil test based application of 125% NPK ha-1 as TNAU-WSF with sulphur (S) and TNAU LMM recorded significantly higher in plant height (54.01 cm), the number of leaves per bulb (8.56), leaf greenness (67.5 SPAD), root length (5.42 cm), polar bulb diameter (4.38 cm), equatorial bulb diameter (2.72 cm) fresh bulb weight (74.21 g), bulb yield (1751 t ha-1) and quality attributes like total soluble solids (TSS) (14.78 °Brix), ascorbic acid content (15.34 mg 100 g-1), pyruvic acid content (2.27 µmol g-1). However, soil test based application of 100% NPK ha-1 as TNAU-WSF was found to be an ideal rate to attain the economic target yield of the onion crop.

Application of Bacillus subtilis on red onion (Allium ascalonicum)

The increase of public consumption of red onion urge the increased production in order to meet consumer needs. To increase red onion production, it is necessary to formulate cheap and easy technology. This study aims to examine the effect of Bacillus subtilis on the growth and production of red onion (Allium ascalonicum). The research was conducted at the Laboratory of Plant Diseases, Department of Plant Pests and Diseases and Experimental Fam Land, Faculty of Agriculture, Hasanuddin University Makassar. The study was conducted from February to April 2020. 80-days old red onion were treated with Bacillus subtilis bacteria consisting of 4 levels, namely control (p0), 104 density (p1), 108 density (p2), and 1012 density (p3). The results showed that the application of Bacillus subtilis affected the number of leaves, number of stems (tillers), number of bulbs, bulbs diameter (mm), and bulbs wet weight per plant (grams) with the best treatment at a density of 108 (p2). The rate of sprouting was not affected by the application of Bacillus subtilis.

Impact of organic and inorganic fertilizers on growth, yield and economics of garlic (Allium sativum L.)

A field experiment was carried out at Research Farm, College of Agriculture, Indore (Madhya Pradesh) during winter season 2020-21 to study the impact of organic and inorganic fertilizers on growth, yield and quality of garlic. The experiment comprising of organic-cum-inorganic sources of nutrients was laid out in randomized block design with three replications. Results revealed that application of 50% RDF along with 2.5 t VC ha-1 + 1.5 t PM ha-1 brought about maximum growth and yield-attributing parameters ( plant height 87.4 cm, leaves 10.8 / plant, leaf length 51.3 cm, leaf width 2.10 cm, LAI 2.42, neck thickness 1.55 cm, bulb weight 42.90 g, bulb diameter 5.78 cm and cloves 27.5/ bulb) as well as bulb yield ( 103.54 q ha-1), net income ( Rs. 230630 ha-1) and B: C ratio ( 3.88). The second best treatment was 50 % RDF + 5 t VC ha-1 with 98.24 q ha-1 yield, and net income of Rs. 214980 ha¬-1. Similarly, the maximum value of TSS (40.15 oBrix) was recorded under the 50 % RDF + 2.5 t VC + VC + 1.5 t PM ha-1. The overall trend indicated that combined application of VC and PM was found superior than their separate application along with RDF.

Performance Evaluation of Onion Varieties at Biyo Awale Cluster in Diredawa Administration

Onion (Allium cepa L.) is an important crop worldwide. It is important in the daily Ethiopian diet. It is widely produced by small farmers and commercial growers throughout the year for local use and export market. No strong study has been conducted to evaluate the suitability of onion cultivation in Biyo Awale district of Diredawa. Hence, the present experiment was conducted to study the performance of improved varieties of onion for their suitability for cultivation in Biyo Awale district of Diredawa. The study was carried out during 2018-2019 cropping season to test the performance of onion varieties. Five high yielding onion varieties were planted in complete randomized block design experiment with three replications including local check at farmer’s field. The quantitative data on bulb yield, plant height, bulb size and number of leaves of onion varieties were collected. Harvesting was done and weighed when all onion varieties reach maturity (90% tops down). The results revealed that the tested onion varieties differ significantly for leaf length, leaf number, neck diameter, bulb diameter, average bulb weight and bulb yield. Among the varieties Bombay red and Melkam produced higher bulb yield (25.56 and 21.13 t ha -1 ) and gave 140.68% and 98.96% yield advantage over local check varieties, respectively. Therefore, Bombay Red and Melkam varieties were recommended to the study area and similar agro-ecology. Keywords: Bulb yield, Onion, Varieties DOI: 10.7176/ALST/90-01 Publication date: November 30 th 2021

The yield potential and chemical analysis of some introduction sweet cultivars in the Papua highlands

The research aims to identify the adaptability some Cilembu sweet potato clones in the highland region of Papua and to determine consumer responses to sweet potato clones Cilembu. The activities carried out in Jayawijaya and Yahukimo. The experiment were 10 cultivars / clones of yams consisting of 6 (six) clones Cilembu and four (4) local sweet potato clones of each: UP-UM 1 (V1), UP-UM 4 (V2), UP-UM 5 (V3), UP-UM 6 (V4), UP-UM 9 (V5), Rancung (V6), Papua Salosa (V7), Helaleke (V8), Cangkuang (V9), and Weayuken (V10). The experiment were conducted on two districts with a height above sea level (asl) different namely Jayawijaya (1550 m asl) and Yakuhimo (2000 m). Assessment was laid out using a randomized block design (RBD) with three replications. The assessment results in districts Jayawijaya shows that, clones Cilembu UP-UM1, UP-UM 5, UP-UM 6, UP-UM 9, and Rancung, as well as varieties lonkal Papua Salosa compounds containing β-carotene / Antocianin shown from yellow / orange / purple. In the district of Jayawijaya, average tuber longest and largest bulb diameter produced by local variety Cangkuang. But the number of tubers were generated by clones Cilembu UP-UM 5. Productivity and highs of 10 varieties / clones were studied both in Jayawiya and Yakohimo is Cangkuang (23.59 t / ha), while the highest dry matter content produced by clone up- UM 4. Production of dry matter produced by the highest Weayuken varieties. The results of the chemical analysis of the highest protein content produced by clone UP-6 and UP-UM UM 9; The highest content of starch and amylose varieties produced by Cangkuang; The highest content of reducing sugar produced by clone UP-6 and UP-UM UM 9; The highest content of β-carotene produced by UP-UM 5; and the highest content of vitamin C is produced by UP-UM 6.

The Isolation and Characterization of Phosphate Solubilizing Bacteria from the Onion Rhizosphere and Their Effect on Onion Growth

In this study 269 phosphate solubilizing bacteria (PSB) strains were isolated from onions rhizosphere. The 15 most efficient PSB were selected. Based on BIOLOG profiling and the LOPAT test system, the strains were identified as Enterobacter cloacae (7), Yersinia intermedia, Pantoea agglomerans, Bacillus subtilis(2), Bacillus pumilius, Lysinibacillus sphaericus and Bacillus atrophaeus(2). The PSB effect on onion growth was investigated under greenhouse conditions. These PSB increased plant height (11.7 to 38.8%), the number of leaves (3 to 70%), the bulb diameter (6.4 to 64.5%), the average root length (2.6 to 44.7%), the fresh weight of the bulb (2.9 to 34.1%) and the dry weight of the bulb (1.5 to 40.6%) when compared to the negative control. Among these strains the most effective inoculants werethe highest P solubizing E.cloacae EB-14 and E. cloacae OB-169 strains, which significantly increased all parameters compared to the commercial plant activator ISR 2000. These results demonstrated the potential use of these PSB as inoculants for onion growth.

English

The field experiment were performed on the site of Werer Agricultural Research Center (Ethiopia)&nbsp; to study optimal irrigation scenario by taking in to account the leaching requirement and drainable excess water for three successive years. Six irrigation treatments were evaluated at different growth stages of onion plant namely at initial growth stage four irrigation event&nbsp; 23 mm (T1), 16.2 mm (T2) 21.0 mm (T3), 13.8 mm (T4), 27.0 mm (T5), 19.8 mm (T6), at development growth stage five irrigation event 32.4 mm (T1), 23.4 mm (T2), 28.8 mm (T3), 19.2 mm (T4), 36.6 mm (T5), 27.0 mm (T6), at mid growth stage four irrigation event 53.4 mm (T1), 37.2 mm (T2), 48.0 mm (T3), 31.8 mm (T4), 60.6 mm (T5), 44.4 mm (T6), and at late stage two irrigation event 58.0 mm (T1), 40.8 mm (T2), 53.4 mm (T3), 35.4 mm (T4), 67.2 mm (T5), 49.2 mm (T6) applied respectively. The irrigation amount and amount of water added for leaching had no significant difference on onion bulb diameter and bulb length across the years. The highest marketable yield (21784 kg/ha) and water use efficiency (1.89 kg/m3) were recorded at the first year. The maximum bulb diameter were recorded from T6 (5.41 cm) and the lowest recorded from T2 (4.81 cm). Treatment T2 were recommended for the production of onion at middle awash. The developed optimal irrigation scheduling and drainable excess water can be used as a guide to yield potential allocation decision related to soil salinity management.&nbsp; Key words: Drainage, optimal, leaching, onion.&nbsp; &nbsp;