High Bulb Research Articles

Nutrient management of shallot (Allium cepa Aggregatum group) in Riau peatlands, a pot experiment

Peatland degradation might affect peatland functions. Sustainable agriculture practice, i.e., nutrient management, is one of the efforts that could be made to delay the degradation. Therefore, this research aimed to identify the best nutrient management practice for shallot production in degraded peatlands. A split-plot experimental design was performed in a greenhouse environment, with cultivars (Sembrani and Trisula) as the main plot and eleven combinations of NPK fertilizer as the subplot. All treatments received 4.4 t ha-1 dolomite to increase the soil pH. Results showed that Sembrani produced a higher bulb yield than Trisula. Trisula was sensitive to acidic soils and failed to yield a high bulb. The NPK recommended dose for Sembrani was 150 kg N ha-1, 100 kg P2O5 ha-1, and 100 kg K2O ha-1, producing 57.50 g plant-1 equal to 14.4 t ha-1 or 53% higher than the control (without NPK). Meanwhile, growing Trisula was not recommended for peatlands.

Growth and yield of shallot (<em>Allium ascalonicum</em> L.) as influenced by soil application of liquid urea and cow urine

This experiment was carried to evaluate the effect of liquid urea and cow urine with cow dung on the economic yield of shallot (Allium ascalonicum L.) in the Eastern Province of Sri Lanka. The experiment was arranged in a Completely Randomized Design (CRD) with eight replicates and six treatments namely, T1: 20 g cow dung, T2: 20 g cow dung + 3% urea, T3: 20 g cow dung + 3% cow urine, T4: 30 g cow dung, T5: 30 g cow dung + 3% urea, and T6: 30 g cow dung + 3% cow urine. The soil applications of liquid urea and cow urine were done as top dressing at two weeks interval from 3rd week after planting (WAP). Data were collected at 3rd, 5th, 7th, and 9th WAP and at harvesting stage. The results revealed that there were significant (P<0.001) variations in plant height, number of bulbs, bulb diameter, fresh weight of single bulb, number of roots, root length, dry weight of leaves, dry weight of bulbs per plant and bulb yield per unit land among the treatments. Relatively higher yield (37.5 t/ha) was obtained from the plants treated with 30 g cow dung and 3% urea (T5) than other treatments whereas 20 g cow dung alone (T1) produced the lowest yield (8.4 t/ha). T6 (30 g cow dung and 3% cow urine) gave 32.6 t/ha bulb yield. It was also noted that there was no remarkable (P>0.05) difference in the bulb yields between T2 and T3. However, significant variation was observed between T5 and T6. The combined effect of cow dung and liquid urea fertilizer increased the onion yield. From this study, it could be stated that 30 g cow dung with 3% urea or 3% cow urine could give high bulb yield in the shallot cultivation at rural areas in Sri Lanka where farmers could easily collect the locally available materials for crop production in ecofriendly manner.

Onions Selected for Reduced Symptom Expression of Iris Yellow Spot Have Higher Photosynthetic Rates

Bulb onion (Allium cepa L.) is an economically valuable vegetable crop in the United States. Onion production is threatened by onion thrips, which are the vector for Iris yellow spot virus, which is the causal agent of Iris yellow spot (IYS). New Mexico State University (NMSU) breeding lines 12-236, 12-238, 12-243, and 12-337 have exhibited fewer IYS disease symptoms in the field; however, little is known about the effects of the disease on the photosynthesis rate (Pn). We hypothesized that these NMSU breeding lines would have a higher Pn than IYS-susceptible cultivars Rumba and Stockton Early Yellow. To test this hypothesis, a field study was conducted for 3 years at NMSU, and Pn was measured five times throughout each season at 2-week intervals. During bulb development and maturation, which occurred at 10 and 12 weeks after transplanting, all NMSU breeding lines exhibited a higher Pn when compared with that of an IYS-susceptible cultivar. Pn was highest at the end of the vegetative growth stage and decreased as bulbs approached maturation for all cultivars. Additionally, a high Pn at 10 and 12 weeks after transplanting coincided with high bulb weight at harvest. NMSU breeding lines have increased Pn compared with that of IYS-susceptible cultivars and resulted in larger and more marketable bulbs. These results indicate that maintaining Pn may be related to reduced IYS symptom expression of onion.

Effect of nitrogen and naphthalene acetic acid on the growth and yield of summer onion

The experiment was conducted to study the response of summer onion to N2 and Naphthalene Acetic Acid (NAA). The experiment consisted of two factors. Factor A: 4 levels of Nitrogen viz. N0-0kg (control), N1-90kg ha-1, N2-110kg ha-1 and N3-130kg ha-1 and Factor B: 4 levels of NAA viz. H0-0ppm, H1- 50ppm, H2-100ppm and H3-150ppm. The experiment was laid out in Randomized Complete Block Design with three replications. Results revealed that in terms of nitrogen, the highest bulb diameter (4.90cm), bulb weight plant-1 (51.48g) and bulb yield ha-1 (17.78t) were found from N2 (110kg N ha-1). In case of application of NAA, the highest bulb length (3.22cm), bulb diameter (4.38cm), bulb weight plant-1 (45.18g) and bulb yield ha-1 (15.49t) were recorded from H2 (100ppm NAA). Regarding combined effect of nitrogen and NAA the highest bulb length (3.76cm), highest bulb diameter (5.26cm), highest bulb weight plant-1 (55.50g) and highest bulb yield ha-1 (19.60t) were recorded from the treatment combination of N2H2. Considering economic analysis, the highest BCR (2.39) was also obtained from N2H2 (110kg N ha-1 with 100ppm NAA) treatment combination.

VARIABILITY, CHARACTER ASSOCIATION AND PATH ANALYSIS OF YIELD AND YIELD CONTRIBUTING TRAITS IN GARLIC (Allium sativum L.)

Ten genotypes of garlic (Allium sativum L.) were evaluated based on yield and yield contributing traits at Sher-e-Bangla Agricultural University, Dhaka during November 2017 to march 2018. In this experiment ten garlic genotypes viz. BARI Rosun-1(G1), BARI Rosun-2 (G2), BARI Rosun-3 (G3), BARI Rosun-4 (G4), Faridpuri (G5), China Rosun (G6), Natori (G7), Ekdana (G8), Khude (G9), Manikganji (G10) were used as experimental materials. The experiment was laid out in Randomized Complete Block Design (RBCD) with three replications. Mean performance, variability, genotypic and phenotypic correlation coefficient and path analysis on different yield contributing characters and yield of garlic genotypes were estimated. The highest bulb yield/plant (13.57) was recorded in the genotype of BARI Rosun-3, whereas the lowest bulb yield/plant (9.007) from the genotype of BARI Rosun-2. Analysis of variance revealed that there were significant genotypic variation among the genotypes for all the characters of this study. Phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all the yield contributing traits. In correlation study, yield per bulb positively and significantly correlated with root length, bulb length, bulb diameter and dry weight per bulb at both genotypic and phenotypic levels respectively. Path coefficient analysis revealed highest positive indirect effects on yield per bulb were obtained by Plant height (13.921), leaf length (6.754), dry weight per bulb (3.552), bulb diameter (2.132), root length (1.91) and total number of leafs (1.629). Considering more dry weight of bulb, maximum bulb length, bulb diameter, no. of leaves, leaf length and plant height genotypes BARI Rosun-3, BARI Rosun-1 may be selected for garlic production.

Effect of integrated weed management practices on yield and quality of onion (Allium cepa L.)

Weed in onion field is a big problem causing yield loss and also need special care that increases cost of cultivation. Among the various options available for eradicating weed problem an experiment on integrated weed manage-ment (IWM) practice was conducted during the Rabi season of 2016-17 at Horticultural Research Farm, Department of Horticulture, Babasaheb Bhim-rao Ambedkar University, Lucknow with an aim to find out a suitable feasible method for the onion field at this area. The experiment was conducted in Randomized Block Design with nine treatments [Control, Hand weeding at 20 & 40 DAT, Weed free, Oxyfluorfen @ 100 g ai/ ha, Pendimethalin @ 750 g ai/ha, Agil @ 100 gi/ha, Oxyflurfen@100 g ai/ha + Hand weeding at 40 DAT, Agil @ 100 g ai/ ha+Hand weeding at 20 DAT, Oxyflurfen @ 100 g ai/ha + Agil @ 100 g ai/ha] and three replications. Minimum fresh weight and dry weight of weed at 90 DAT was recorded by weed free condition, which also increase buld yield and quality parameters recording higher bulb weight (95.72 g), bulb yield (302.67q/ha), bulb diameter (6.48 cm), number of scales per bulb (8.40) and better quality parameters like recording maximum ascorbic acid (12.07), TSS (12.90), total sugars (18.30), reducing sugars(8.51) and non-reducing sugars (9.76) followed by application of Pendimethalin @750g a.i./ha. Thus, it is concluded that weed free condition is the best for onion pro-duction.

Degenerescence of virus-free garlic cultivars in altitude conditions in the Semiarid region of the Northeast of Brazil

ABSTRACT It is necessary to use virus-free garlic seeds to reach high bulb yields; however, information is needed on the number of generations that these seeds can be grown in field conditions without decreasing bulb yield and quality due to degeneration. Degeneration is dependent on the production season and locality; thus, the objective of this work was to evaluate the degeneration of virus-free garlic cultivars grown in the Semiarid region of the Northeast of Brazil, through three experiments conducted in Portalegre, state of Rio Grande do Norte. Virus-free garlic cultivars were used in the first generation (G1) and second-generation (G2) and cultivars without clonal cleaning (infected) in the third experiment. The experiments were conducted in randomized blocks experimental design, with four replications. The treatments consisted of five cultivars: Amarante, Branco Mossoró, Cateto Roxo, Gravatá, and Hozan. The use of G2 garlic seeds in field conditions is viable, mainly for the cultivars Branco Mossoró and Hozan, which showed lower production losses. However, further evaluations, considering at least four generations, are necessary for these cultivars, since the degeneration level depends on the crop environment.

Japanese Bulb Onion: Production, Consumption, and Cultivars

Abstract Bulb onion is an ancient vegetable crop that has been cultivated for at least 5,000 years. In Japan, this cultivation has only 150 years of history, but nowadays, it ranks fourth in total production, fourth in cropping acreage, and second in consumption among vegetables grown domestically. Until the 1970s, open-pollinated onion cultivars were predominantly cultivated throughout the country; they were selected mainly from old US cultivars. Over the past three decades, these open-pollinated cultivars have been replaced with F1 hybrid cultivars that offer higher yield, better disease resistance, uniformity at maturity, and high bulb quality. In this review, an attempt is made to characterize the commercial production and consumption of Japanese bulb onion as well as agronomic characteristics of representative cultivars.

Optimization of Copper Sulphate Levels to Enhance Yield and Quality of Aggregatum Onion (Allium cepa var aggregatum L)

Field experiments were conducted during rabi season of 2018 and summer season of 2019 at farmer’s field, western zone of Tamil Nadu at Pattiyarkovilpathy, Theethipalayam and Narasipuram villages of Thondamuthur block of Coimbatore district. Totally five treatments comprising of varied CuSO 4 levels (0, 2.5, 5.0, 7.5 & 10.0 kg ha-1) were replicated four times in a randomized block design under irrigated conditions. The results showed that, fresh mean bulb yield of onion in four locations ranged from 12.4 to 15.6 t ha-1. The highest mean bulb yield of 15.6 t ha-1 was registered with recommended NPK+5 kg CuSO4 ha-1 and the lowest mean bulb yield of 12.4 t ha-1 was recorded in NPK control with no CuSO 4 addition. Dry Matter Production ranged from 1065 to 1199 kg ha-1. The highest DMP of 1199 kg ha-1 was recorded in the treatment that was applied with NPK+5 kg CuSO4 ha-1 and the lowest DMP (1065 kg ha-1) was noticed with NPK control. Concerning copper content in bulb and foliage, it ranged from 6.09 to 12.3 and 8.46 to 13.7 mg kg-1 with the location mean of 6.16 to 12.0 mg kg-1 and 7.61 to 11.1 mg kg-1, respectively. Copper uptake in bulb and sheath varied from 7.05 to 18.3 and 6.26 to 11.0 g ha-1 (mean of 8.55 to 12.3 and 6.52 to 10.4 g ha-1), respectively with a total uptake of 14.1 to 27.6 g ha-1. In both bulb and foliage, Cu content and uptake, increased with increasing doses of CuSO 4 and the highest Cu content and uptake was registered with the application of CuSO4 @ 10.0 kg ha-1. Regarding the availability of copper in soil, it ranged from 0.73 to 2.42 mg kg-1 and increasing levels of CuSO4 application increased the DTPA Cu status in soil and application of 10.0 kg CuSO 4 ha-1 recorded the highest copper availability in soil. Quality parameters viz., TSS, titrable acidity and ascorbic acid varied from 10.25 to 14.08 oBrix, 0.28 to 0.61% and 12.9 to 20.1 (100 g-1FW), respectively. Field experiments conducted to optimize the rates of copper sulfate application to improve the yield and quality of aggregatum onion in four locations at Coimbatore district, showed that, soil application of 5 kg CuSO4 along with recommended NPK @ 60:30:30 kg ha-1 was found optimal for obtaining higher bulb yield (15.6 t ha-1) and better quality in aggregatum onion with a BC ratio of 4.63.

Indirect Evaporative Cooling: An Efficient and Convenient Energy System

Evaporative cooling is now an alternative method for the conventional air cooling method. This method does not only save energy but also protect the environment from global warming and hazardous gases. Thus this system is highly efficient and eco-friendly. Evaporative cooling system is further divided into two categories that are direct evaporative cooling system and an indirect evaporative cooling system. The direct evaporative cooling system is not much efficient due to high wet bulb temperature and moisture thus rather than using the direct evaporative cooling system the indirect evaporative cooling system is preferred. This paper discusses comparative studies of performance, working principles, material selection criteria’s and various methods. It also explains the performance under different weather conditions, hybrid structure to reduce the load on the further system. It summarises various aspects like wick attained aluminium sheet is the best material for IEC or counter-flow heat exchanger is effective than parallel-flow heat exchanger. It finally results that indirect evaporative cooling system is moisture free, very effective and environment savings. That can be used in various residential and commercial sectors effectively as an alternative for conventional energy-consuming system.

Virus-free garlic: yield and commercial classification as a function of plant spacing and seed size

ABSTRACT Studies on the interaction between garlic plant density and virus-free seed size are scarce in Brazil. Thus, this study was installed to evaluate the effect of plant spacing and seed size on garlic traits and yield for infected and virus-free bulbs. Treatments were arranged in a randomized block design and 2x5x3 factorial combination [infected and virus-free bulbs, five plant spacings (210, 260, 300, 360, and 390 cm2 per plant), and three bulbous seed sizes (sieve one, two, and three)]. The highest bulb yield was observed for virus-free seeds at a plant spacing of 390 cm2 plant-1, while the highest commercial yield was verified for 210 cm2 plant-1 spacing. The combination of virus-free seeds, larger bulbs, and 332 cm2 plant-1 spacing promoted the highest leaf area index. For virus-free garlic, lower plant densities resulted in higher yields and garlic bulb quality. The best option for higher yields and improved commercial quality bulbs was the use of medium-sized virus-free bulbils at a plant density of about 300 thousand plants ha-1.

Impact of Drip Fertigation on Weed Population, Dry Weight and Yield of Onion in Semiarid Tropical Region of India

Field demonstrations were conducted during rabi season for two years in seven locations of Tiruppur District, Tamil Nadu state to study the weed density under drip fertigation and conventional method of cultivation (Farmer’s practice). Nine weed species emerged with a frequency of more than 50% irrespective of the locations. Drip fertigation with recommended dose of fertilizers (RDF) produced the highest bulb yield of onion when compared with the conventional method of cultivation. Total population of weeds and weed dry weight were minimum under drip fertigation.

Field efficacy of newer insecticides against onion thrips Thrips tabaci Lindeman

Field experiments were conducted for two consecutive seasons (kharif and rabi) during 2017–18 to evaluate the efficacy of three newer insecticides, including cyantraniliprole (@ 90 & 120 gm ai/ha), emamectin benzoate (@ 11 & 22 gm ai/ha), tolfenpyrad @ 125 ai/ha along with a conventional insecticide, profenofos @ 160 ai/ha. A total of seven treatments, including untreated control, were imposed with a randomized block design having three replications. All the insecticides were found effective against thrips. Profenofos @ 160 ai/ha was the most effective with reduction of 86.8–90% of population of thrips, low leaf curing and a maximum bulb yield (20.8–24.2 t/ha). Cyantraniliprole @ 120 gm ai/ha was the next best with 73.879% decrease of thrips population, low leaf curling index and higher bulb yield (20.9–22.1 t/ha) and was on par with profenofos.

Evaluation of Alternate, Fixed and Conventional Furrow Irrigation Systems with Different Water Application Level on Onion Yield in Dubti, Afar, Ethiopia

Water scarcity is a major constraint for the production of food in arid and semi-arid areas. Therefore, deficit irrigation and application of irrigation systems are important concerns to improve water use efficiency without significant yield loss. The objective of an experiment was evaluating the performance of furrow irrigation systems under different water application levels on onion yield. The treatments were three deficit irrigation levels of 50%, 75% and 100% of ET C with three furrow irrigation systems and laid out a factorial RCB design with three replications. The highest bulb yield and water use efficiency were obtained from CFI 100% and AFI 100% respectively. Bulb yield of CFI 100%, CFI 75%, and AFI 100% were not shown a significant difference which is 25.46 ton/ha, 24.88 ton/ha, and 24.54 ton/ha respectively, besides better water use efficiency of 8.39 kg/m 3 was recorded from AFI 100%. In relative to the control, AFI 100% able to increase 0.868 ha net additional irrigable land per each hectare. Therefore, it can be decided that Alternative furrow irrigation with 100% ET C increased water use efficiency and can solve a problem of water shortage. Keywords : Alternate Furrow; Crop Water Requirement; Deficit Irrigation; Onion; Water Use Efficiency DOI : 10.7176/IEL/9-5-03 Publication date :June 30 th 2019

Effects of Different Level of Nitrogen Fertilizer Application on Growth, Yield, Quality and Storage Life of Onion (Allium cepa L.) at Jimma, South Western Ethiopia

Onion (Allium cepa L.) is one of the most important vegetable crops produced in Ethiopia. Yield and productivity of the crop has been far below the regional and national standards owing to several factors; absence of location specific fertilizer recommendation being the major among others. In Ethiopia, post harvest loss of vegetables contributed up to 30% yield reduction. Thus, a field experiment was conducted at Jimma University College of Agriculture and Veterinary Medicine Research field during dry season to study the effects of Nitrogen fertilizer application on growth, yield, quality and storage life of irrigated onion under Jimma condition, South Western Ethiopia. The treatments consisted of four levels of Nitrogen (0, 50, 100 and 150 kg N ha -1 ) that laid out in Randomized Complete Block Design with three replications. Data on growth, yield, bulb quality and storage life parameters were recorded and analyzed using GenStat 12.1 version computer soft ware packages. Results of the study revealed that; Nitrogen fertilizer applications had shown a highly significant effect on growth, yield and quality of onion. Similarly, the keeping qualities of the Onion bulbs are highly influenced by application of N at different levels. Excessive application of Nitrogen fertilizer caused higher bulb rots (%); bulb sprouts (%) and weight loss (%) during the three month storage time at ambient temperature. This can be recommended for use by potential onion investors or farmers in the study area. Keywords : Growth, Nitrogen, Onion, Quality, Storage life, Yield. DOI : 10.7176/JNSR/9-10-05 Publication date :May 31 st 2019

Response of mulching and weed management practices on weed control, yield and economics of garlic

A field experiment was conducted during rainy season of (Kharif) 2014 and 2015 at Main Research Station, Hebbal, Bengaluru to know the bio-efficacy of different herbicides against weeds and their effect on growth, yield of garlic and to study the integrated impact of mulching and herbicides on weed growth and to know phytotoxicity effect, if any. The experiment was laid out in a split-plot design with ten treatments, comprising with and without paddy straw mulch 5.0 t/ha in main-plot and weed management methods like pendimethalin at 1.0 kg/ha, oxyflurofen at 0.22 kg/ha, oxadiargyl at 0.14 kg/ha, manual weeding twice at 20 and 40 DAS and weedy check in sub-plot. Results revealed that among weed management practices, significantly higher bulb yield was obtained in oxadiargyl 0.14 kg/ha (6.6 t/ha in 2014 and 6.2 t/ha in 2015), at par with manual weeding (6.5 t/ha in 2014 and 6.0 t/ha in 2015), due to lower weed density and dry weight resulting in higher net returns and benefit:cost ratio.

Studies on genetic variability, heritability and genetic advance in long day onion (Allium cepa L.) genotypes

Onion (Allium cepa L.) is a globally famous vegetable and is used in a variety of ways, including eaten fresh, added as a spice or prepared as a main ingredient in cooking. Pungent and sweet taste, texture, and several other qualities are required for onions to be suitable as processing ingredients. In this study the evaluation of onion genotypes for growth, yield and quality in hill condition in order to achieve more production and productivity objective. However, there is great potential for increasing area, production and productivity of this crop in the hill region, and hence, there is an urgent need to evaluate different long day onion genotypes. Therefore, significant variation among the 50 genotypes of onion was observed for all the traits viz., plant height, leaf length, number of leaves/plant, polar and equatorial diameter of bulbs, average bulb weight, total soluble solids, percentage of grade (A, B and c) of bulb, total yield (q/ha) and % weight loss after 2 month of storage. It was also observed that moderate for bulb weight was positively associated with polar diameter and length of bulb. For improving bulb yield component traits in onion, the generation of genetically broad base population using diverse genotypes in breeding programme is advocated. the highest bulb yield (1061.30 q/ha) was recorded in genotypes oN-15-33, followed by 911.70 q/ha and 889.10 q/ha in oN-14-23 and oLr-1343, respectively. the weight loss % after 2 months of storage recorded minimum in genotypes oN-1388 (3.33%). Estimates of heritability in number of leaves/plant (18.60%) and total bulb yield q/ha (99.00%). the average bulb weight and yield/m2 is positively correlated with bulb yield (q/ha).

Morphological and Biochemical Diversity of Shallot Landraces Preserved Along the Croatian Coast.

Shallots are a valuable minor Allium crop, and are propagated vegetatively and maintained in home gardens across generations along the Croatian coast and island areas. Shallot landraces growing along the Croatian coast fall into three genotypes: Allium cepa Aggregatum group (2n = 2x = 16), A. × proliferum (Moench) Schard. (2n = 2x = 16), and A. × cornutum Clementi ex Vis. (2n = 3x = 24), among which A. × cornutum is the most widespread. The aim of this study was to differentiate shallot accessions collected from local farmers using morphological markers. Also, the chemical composition including phenolic content, phenolic profile, total antioxidant capacity, and mineral composition, of shallot accessions was compared with that of the local landraces of common onion, and with market available shallot and common onion cultivars. Based on morphological observations and using multivariate classification, shallot landraces were classified into three distinct groups. Properties, based on which A. × cornutum can be differentiated from A. cepa Aggregatum and A. × proliferum, are stamen morphology, stamen length, leaf and scape vegetative properties, number of bulbs in cluster, cluster mass, and bulb diameter. Flower diameter and flower pedicel length differentiate A. × cornutum and A. × proliferum from A. cepa Aggregatum. Significant variability was observed in the biochemical profiles across tested accessions. Compared with the commercial common onion cultivars, local shallot accessions have higher bulb N, P, and K content. The major phenolic compounds identified in shallots were quercetin-4′-glucoside and quercetin-3,4′-diglucoside. Additionally, several other minor phenolic compounds were also identified. Morphological and biochemical profiles were evaluated using Partial Least Square (PLS) analysis. Specific morphological traits and biochemical markers for possible species identification are proposed.

Development of seed propagated shallot (Allium cepa L var. aggregatum) varieties in Ethiopia

Abstract Shallot is one of the major vegetable crops used for seasoning local cuisines in Ethiopia. It is propagated vegetatively using bulbs as planting material. However, the use of bulbs as planting material is not advisable, because bulbs are expensive, bulky to transport, transmit diseases from one generation to the next, and have short shelf life. As a result, production of shallot decreased considerably in favor of the seed propagated onions. To reverse the trend, a study was undertaken to develop shallot varieties that can be propagated through seed. In the first phase of the development, sixty nine shallot accessions, that could bolt and produce seeds, were identified. Three accessions (DZSHT-91-2B, DZSHT-193-1A and DZSHT-157-1B), which had desirable bulb characteristics were developed through recurrent positive selection from 2008 to 2014. Then the three varieties were compared with an onion variety Bombay Red, a vegetatively propagated shallot variety Minjar and an introduced seed propagated shallot variety Vethalan. The trials were lied out in Randomized Complete Block Design with three replications at three different agro-ecological locations. The results of the study showed that the three varieties, in addition to mitigating the aforementioned problems, had 44–86% higher bulb yield and higher proportion of big and medium size bulbs as compared to shallot variety Minjar. The yield and total soluble solids (TSS) of the varieties were comparable with Bombay Red and Vethalan varieties. The three selected seed producing cultivars also produced seed yield of 6.0–10.4 g per plant. Therefore, the varieties will benefit shallot bulb and seed producers, transporters and traders.

Onion crop response to different irrigation and N-fertilizer levels in dry Mediterranean region

Due to the water scarcity in dry Mediterranean condition, determination of water and nitrogen (N) fertilizer needs is a major challenge for crop production and environment protection. Pot experiments under open field conditions were conducted for two consecutive years (2016 and 2017) to assess the effects of various levels of N-fertilizer and irrigation on onion crop, following a 4×3 factorial experiment arranged in a randomized block design with four N-fertilizer rates (0, 40, 80, and 120 kg N ha-1), and three irrigation levels (100, 80, and 60% of the seasonal water use), with three replications. Results indicated that the initial soil N-content (about 60 kg N ha-1) was sufficient to meet crop nitrogen requirements. However, results indicated that onion crop was sensitive to water stress, so that the highest total bulb yield (BY, 19.1 t ha-1), dry matter in bulbs (DM, 2.97 t ha-1), and water productivity (WP, 1.9 kg m-3) were found under full irrigation compared to the deficit conditions. BY, DM, and WP were predicted to be increased linearly with increasing levels of irrigation. The developed equations could be used for predicting onion crop yields under similar agro-pedo-climatic context, and as a tool for rational management of limited irrigation water.