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Introduction: The selections of optimum planting date for every climate and mother bulb size are important factors affecting the quantity and quality of seed production in different cultivars. This study was performed in Isfahan province, Frieden, during two growing years 2016-2017 to determine the effect of planting time and mother bulb size on the quantity and quality of short-day onion seed varieties Texas Early Grano 502 Materials and Methods: A split-plot experiment was performed in a randomized complete block design with four replications. The main factor was cultivation dates at four levels: the end of August, the first of September, the end of September and the first of October and mother bulb size at three levels with 3.55, 5.5- 7, 7.5-9cm diameters were assigned as sub-plots. The measured traits were number of umbel per unit area, the number of fertilized capsules in umbel, the number of seeds per capsule, 1000 seed weight, seed yield and germination rate. Results: The results of combined analysis of variance showed that effect of year was only significant on the number of capsules per umbel at p<0.01. The interactions of year× mother bulb diameter and year× planting date× mother bulb diameter was not significant for any of the traits. The traits were not affected by the year. The results showed that the planting date had a significant effect on all traits except for 1000 seed weight, and the first planting date (the end of August) had the highest values in all traits. The highest germination percentage (89.83%) and the highest germination rate (12.8) were obtained on the first planting date, which showed a statistically significant difference with the subsequent planting dates. However, these two traits were not affected by mother bulb diameter treatment. The highest seed yield for onion diameter factor (505.65 kg h-1 in the first year and 465.78 kg h-1 in the second year) was associated with mother bulb size of 7.5-9 cm. Conclusions: The overall result showed that to obtain the highest and most desirable quality of onion seeds of Texas Early Grano 502 cultivar in Friedan of Isfahan, the planting date of the first of September and the size of the mother bulb “between” 7 to 9 cm is recommended. [ABSTRACT FROM AUTHOR]

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Tuberose (Polianthes tuberosa L.) is an ornamental and medicinal plant, cultivated in tropical and subtropical regions for its fragrant cut flowers and perfume industries, P. tuberosa flowers are the source of the highest-quality tuberose oil that remains today the most expensive raw material in perfumery. Furthermore, bulb size influences the flowering of P. tuberosa L. and creates a problem for tuberose flower production. Aims in this study were climatic condition and bulbs size variation, which were investigated to enhance the bulb size and climatic condition for improving tuberose production in Algeria. A culture of P. tuberosa L. bulbs was conducted in the field and under shelter using different bulb diameters, growing and flowering parameters were recorded for each plant, from planting to maturity. According to the obtained results, a good growth of tuberose was noticed with the big bulbs (diameter≥2 cm), i.e., bulb germination, leaf emergence, and the number of leaves by dominance for the bulbs cultivated under shelter, compared to those grown in the field. Regarding flowering, it was influenced mainly by bulb size, where only big bulbs gave flowers, and flowering characteristics were improved by the under shelter culture neither in the field. In general and according to the present work, for a good growth and for a better production of P. tuberosa flowers, bulbs culture under shelter using bulbs of 2-4 cm in diameter were recommended. [ABSTRACT FROM AUTHOR]

Lilium longiflorum is a wild Lilium, and its flowering transition requires a long period of cold exposure to meet the demand of vernalization. The responses of different sized bulbs to cold exposure and photoperiod are different, and the floral transition pathways of small and large bulbs are different. In this study, small and large bulbs were placed in cold storage for different weeks and then cultured at a constant ambient temperature of 25 °C under long day (LD) and short day (SD) conditions. Then, the flowering characteristics and expression patterns of key genes related to the vernalization and photoperiod pathways in different groups were calculated and analyzed. The results showed that the floral transition of Lilium longiflorum was influenced by both vernalization and photoperiod, that vernalization and LD conditions can significantly improve the flowering rate of Lilium longiflorum, and that the time from planting to visible flowering buds' appearance was decreased. The flowering time and rate of large bulbs were greatly influenced by cold exposure, and the vernalization pathway acted more actively at the floral transition stage. The floral transition of small bulbs was affected more by the photoperiod pathway. Moreover, it was speculated that cold exposure may promote greater sensitivity of the small bulbs to LD conditions. In addition, the expression of LlVRN1, LlFKF1, LlGI, LlCO5, LlCO7, LlCO16, LlFT1, LlFT3 and LlSOC1 was high during the process of floral transition, and LlCO13, LlCO14 and LlCO15 were highly expressed in the vegetative stage. The expression of LlCO13 and LlCO14 was different under different lighting conditions, and the flowering induction function of LlCO9 and LlFT3 was related to vernalization. Moreover, LlFKF1, LlGI, LlCO5, LlCO16, LlSOC1 and LlFT2 were involved in the entire growth process of plants, while LlCO6, LlCO16 and LlFT1 are involved in the differentiation and formation of small bulblets of plants after the inflorescence stage, and this process is also closely related to LD conditions. This study has great significance for understanding the molecular mechanisms of the vernalization and photoperiod flowering pathways of Lilium longiflorum. [ABSTRACT FROM AUTHOR]

Experiments were conducted at Horticulture Research Division (HRD), Khumaltar, Lalitpur; and Horticulture Research Station (HRS), Kimugaun, Dailekh in 2017/18 to evaluate the high yielding open pollinated genotypes of onion in mid hills of both locations. Five onion genotypes namely AVON-1016, AVON-1027, AVON-1028, AVON-1052, AVON-1074 and AVON-1103 received from Asian Vegetable Research and Development Centre were evaluated with local check variety and recommended variety Red Creole in both locations in randomized complete block design with 4 replications. The main objective of the experiment is to findout the high yielding open pollinated onion genotypes for mid hill condition.The pooled analysis of data over locations showed significant differences on plant height, neck diameter, bulb diameter, weight of bulbs and adjusted bulb yield per hectare. Introduced genotypes AVON 1027 (38.83 t/ha), AVON 1052 (31.97 t/ha) and AVON 1028 (31.48 t/ha) produced significantly higher yield than recommended and commercially cultivated check variety Red Creole (27.04 t/ha). Therefore the genotype AVON 1027 can be selected as the best genotype for growing in mid hills of Nepal

Lilium longiflorum is a wild Lilium, and its flowering transition requires a long period of cold exposure to meet the demand of vernalization. The responses of different sized bulbs to cold exposure and photoperiod are different, and the floral transition pathways of small and large bulbs are different. In this study, small and large bulbs were placed in cold storage for different weeks and then cultured at a constant ambient temperature of 25 °C under long day (LD) and short day (SD) conditions. Then, the flowering characteristics and expression patterns of key genes related to the vernalization and photoperiod pathways in different groups were calculated and analyzed. The results showed that the floral transition of Lilium longiflorum was influenced by both vernalization and photoperiod, that vernalization and LD conditions can significantly improve the flowering rate of Lilium longiflorum, and that the time from planting to visible flowering buds’ appearance was decreased. The flowering time and rate of large bulbs were greatly influenced by cold exposure, and the vernalization pathway acted more actively at the floral transition stage. The floral transition of small bulbs was affected more by the photoperiod pathway. Moreover, it was speculated that cold exposure may promote greater sensitivity of the small bulbs to LD conditions. In addition, the expression of LlVRN1, LlFKF1, LlGI, LlCO5, LlCO7, LlCO16, LlFT1, LlFT3 and LlSOC1 was high during the process of floral transition, and LlCO13, LlCO14 and LlCO15 were highly expressed in the vegetative stage. The expression of LlCO13 and LlCO14 was different under different lighting conditions, and the flowering induction function of LlCO9 and LlFT3 was related to vernalization. Moreover, LlFKF1, LlGI, LlCO5, LlCO16, LlSOC1 and LlFT2 were involved in the entire growth process of plants, while LlCO6, LlCO16 and LlFT1 are involved in the differentiation and formation of small bulblets of plants after the inflorescence stage, and this process is also closely related to LD conditions. This study has great significance for understanding the molecular mechanisms of the vernalization and photoperiod flowering pathways of Lilium longiflorum.

Constraints are reported for the low productivity and quality of onion seed production in Ethiopia. Therefore, a field experiment was conducted at Kobo sub-center research station and Libso investment farm to study the influence of planting date and onion bulb size on yield and quality of onion seed. The experiment was laid out in Randomized Complete Block Design with three replications and involved three levels of onion bulb sizes and four levels of planting dates. The results of the study revealed that significant interactions between planting date and mother bulb size on seed yield ton ha-1, germination percentage, seed vigor index I and seed vigor index II. The highest seed yield (2.8 tons ha−1) was recorded from large onion bulbs of a size planted at Kobo early—October. Planted onion bulbs early-October increased seed yield (ton ha−1 by 21.7%) than planted early-November. Regarding onion bulb size, large bulbs increased seed yield (ton ha−1 by 40%) than the small bulbs. The highest (97.3) germination percentage was recorded from large onion bulbs planted at Kobo in early-October. Therefore, for the production of better yield and quality of onion seeds, early-October planting and large onion bulbs (4.1–5 cm) can be recommended in the study areas and other similar agro-ecology areas of the country.

Constraints are reported for the low productivity and quality of onion seed production in Ethiopia. Therefore, a field experiment was conducted at Kobo sub-center research station and Libso investment farm to study the influence of planting date and onion bulb size on yield and quality of onion seed. The experiment was laid out in Randomized Complete Block Design with three replications and involved three levels of onion bulb sizes and four levels of planting dates. The results of the study revealed that significant interactions between planting date and mother bulb size on seed yield ton ha-1, germination percentage, seed vigor index I and seed vigor index II. The highest seed yield (2.8 tons ha−1) was recorded from large onion bulbs of a size planted at Kobo early—October. Planted onion bulbs early-October increased seed yield (ton ha−1 by 21.7%) than planted early-November. Regarding onion bulb size, large bulbs increased seed yield (ton ha−1 by 40%) than the small bulbs. The highest (97.3) germination percentage was recorded from large onion bulbs planted at Kobo in early-October. Therefore, for the production of better yield and quality of onion seeds, early-October planting and large onion bulbs (4.1–5 cm) can be recommended in the study areas and other similar agro-ecology areas of the country. [ABSTRACT FROM AUTHOR]

An experiment was carried out at Horticulture Farm of Bangladesh Agricultural University, Mymensingh during the period from October 2018 to March 2019 to examine the effects of different bulb size viz., large size bulb (15±1 g), medium size bulb (10±1 g), small size bulb (7±1 g) on seed production of two onion varieties (Taherpuri and Kalash Nagari). Significant variation observed in both varieties for most of the parameters based on onion bulb size. The variety Kalash Nagari showed better performances compared to variety Taherpuri. After 60 days of planting, Kalash Nagari variety gave the highest plant height (55.07 cm), number of leaves (20.62), stalk length (100.78 cm), and total seed yield (630 kg ha-1), while in Taherpuri plant height, leaf number, stalk length and total seed weight were 32.21 cm, 6.93, 61.47 cm and 270 kg ha-1, respectively. Large sized bulb gave better performance compared to small sized bulb. The large sized bulb gave highest plant height (49.83 cm) and highest total seed yield (490 kg ha-1). Medium size bulb gave the seed yield (460 kg ha-1) and lowest in small size bulb (390 kg ha-1). Seed yield was significantly affected by the combined effects of variety and bulb size. Kalash Nagari onion with large sized bulb gave the highest seed yield (660 kg ha-1) and Taherpuri variety with small sized bulb gave the lowest seed yield (180 kg ha-1). [ABSTRACT FROM AUTHOR]

This study was performed to depict the anatomical changes in apical meristems in order to determine the flower initiation and development of Iranian lily (Lilium ledebourii). Observations carried out by scanning electron microscope (SEM) on groups of bulbs with different age and size showed that only large (≥55 g and ≥6 cm in diameter) 9-year-old and older bulbs expressed flowering transition, abandoning the juvenile condition. The switch from vegetative to reproductive in the apical meristem was characterized by flattening its dome. Flower initiation started between 10 and 20 days after planting, once the bulbs have passed a period of vernalization of two months at 3°C. The first hint of floral organ definition was noted 30 to 50 days after planting when the outer perianths started to grow followed by inner perianths in a pattern of 3−3. After complementation of flower formation by stamen and pistil appearance and development, flower abortion occurred in some bulbs 30 days after flower initiation. Flower bud abortion could not be linked to the bulb size. Identification of the exact time of flower initiation will be useful to provide proper management of Iranian lily in the process of domestication of this endemic endangered lily.

Twenty three diverse germplasm lines collected from varying agro-ecological regions of Peninsular India during 2007-08 were characterized and evaluated along with three controls viz. Nasik Red, Light Red and White Marglobe, in an augmented block design during kharif 2009-10, at NBPGR Regional Station, Rajendranagar, Hyderabad. The accessions exhibited good variation for qualitative traits like early seedling vigour, leaf cross section, leaf arrangement, stem shape, bulb shape, bulb skin color, bulb size, bulb hearting and bulb flesh colour and quantitative traits like plant height, number of leaves per plant, leaf length, leaf girth, number of scales per bulb, total soluble solids (TSS) (°Brix), bulb weight and bulb yield per plant. Correlation study revealed that high significant positive correlation was recorded between number of scales per bulb and bulb weight (r=0.71) and significant negative correlation was observed between leaf length and leaf girth (r= -0.88), leaf length and bolting (-0.63) among others. Principal component analysis (PCA) revealed that the first four principal components explained 99.76% of the total variation among the 23 accessions and three controls. PCA I accounted for 97.04% of variation, had maximum influence on bulb weight followed by plant height. The PCA II traits were leaf length and plant height which accounted for 1.97 % of the variance. The PCA III and PCA IV have contributed for 0.39 and 0.39% of total variance. The cluster analysis revealed that dendrogram formed four distinct clusters and cluster III was found to be the largest including controls. The promising accessions for bulb weight were IC 571959, IC 564056, IC 571927, IC 571919 and IC 564059, which may be effectively tapped in sound breeding and conservation program.

This study was performed to depict the anatomical changes in apical meristems in order to determine the flower initiation and development of Iranian lily (Lilium ledebourii). Observations carried out by scanning electron microscope (SEM) on groups of bulbs with different age and size showed that only large (≥55 g and ≥6 cm in diameter) 9-year-old and older bulbs expressed flowering transition, abandoning the juvenile condition. The switch from vegetative to reproductive in the apical meristem was characterized by flattening its dome. Flower initiation started between 10 and 20 days after planting, once the bulbs have passed a period of vernalization of two months at 3°C. The first hint of floral organ definition was noted 30 to 50 days after planting when the outer perianths started to grow followed by inner perianths in a pattern of 3-3. After complementation of flower formation by stamen and pistil appearance and development, flower abortion occurred in some bulbs 30 days after flower initiation. Flower bud abortion could not be linked to the bulb size. Identification of the exact time of flower initiation will be useful to provide proper management of Iranian lily in the process of domestication of this endemic endangered lily. [ABSTRACT FROM AUTHOR]

Trackside lubricators are designed to deliver grease to passing wheel flanges to reduce wheel and rail wear on curves. Ensuring that they are set up to deliver sufficient grease for the range of vehicles passing a site can be a challenge. For example, vehicle dynamics modelling and site investigations have shown that the wheels of passenger vehicles do not run as close to the rail face as those of freight vehicles, meaning that they are less likely to contact the grease and lubricate subsequent curves. To investigate the effects of different trackside devices, and the influence of parameters governing grease pickup, including lateral wheel displacement and pump durations, a bespoke test rig was built at the University of Sheffield. The rig used a scaled wheel, a short section of rail and a modern trackside lubricator set-up. Experiments involving different lateral wheel displacements and pumping durations were carried out, in addition to the visualisation of the size of the grease bulb. This showed how a grease bulb grows. It also indicated that a worn profile is likely to require greater wheel displacement to make contact with grease bulbs when compared to a new wheel profile. The experimental results showed that increasing pickup of grease can be expected when an additional component called a GreaseGuideTM was fitted to a regular grease delivery unit (GDU) on the rail. The efficiency of grease pickup was investigated, and test results exploring increasing pump durations have indicated a relationship between pickup and bulb size. To validate the use of the scaled rig, similar tests were carried out using a full-scale test rig. The full-scale results were compared to the experimental results of the scaled wheel rig. This showed that whilst there were differences between the two test rigs in absolute values and anomalous results, overall trends were the same on both test scales. The effect of temperature on bulb size and pumpability of grease was also investigated. This work can be extended further by using the same method to investigate other parameters that affect the lubrication of curves. This can lead to optimised lubricator set-up to ensure that the track is fully lubricated all the time. [ABSTRACT FROM AUTHOR]

The effect of bulb size on storage behavior of onions was investigated in an experiment carried out in Korça region. This study was focused on evaluation of certain bulb characteristics during storage under natural ventilation conditions. The autochthonous cultivar of Miras was involved in the study and three bulb sizes were observed: small, medium and large, with diameters ≤ 3cm, 3-5cm and ≥5cm respectively. The sealed and dries bulbs were placed for storage in the building with natural ventilation. During the storage period, the weight loss, the damaged bulbs and the percentage of sprouted bulbs were estimated. The first two indicators were evaluated for the periods 30, 60, 90 and 120 days of the storage, while the last indicator after 60, 90 and 120 days. The results showed that during storage period, humidity gradually decreases. There were differences of bulb moisture content at different time periods after harvesting depending on their size and storage periods. After 120 days of storage, weight loss of large bulbs was about 23.827%, about 23.604% and 20.263% for small and medium bulbs size respectively. Results indicated that these losses are slightly affected by the size of the bulbs, while the storage period had the greatest impact, whereby the losses increase with the extension of the storage period. The findings raise the need of storage conditions improvement to reduce onions post harvest losses. [ABSTRACT FROM AUTHOR]

The combined application of humic substances and mycorrhizal inocula under increased CO in the air is a promising horticultural technique for improving the quality of greenhouse-grown onion seedlings. The objective of this study was to evaluate if the development and qualitative characteristics of bulbs from the yellow onion Allium cepa L. Alfa São Francisco improved with the application of the abovementioned agronomic, biotic, and environmental factors. The lowest dry matter was achieved in bulbs of onions not inoculated with mycorrhizal fungi, non-amended with humic acids (HA), and grown at ambient CO. Mycorrhizal inoculation significantly increased bulb biomass in plants cultivated at ambient CO, and not fertilized with HA, which may be a consequence of the enhanced acid phosphatase activity in roots. The application of HA always increased bulb dry matter, which were more evident at elevated rather than ambient CO conditions and correlated with improved acid phosphatase activity in the plants at elevated CO. Mycorrhizal inoculation, HA supplementation, and elevated CO in the air had an additive effect of increasing the content of soluble sugars, proteins, and phenolics in bulbs. While high levels of sugars and proteins enhanced the energetic value of onions, the increase in phenolics improved their antioxidant properties. The triple interaction between mycorrhization, HA fertilization, and elevated CO also increased the ratio between soluble solids and total titratable acidity, which may enhance the perception of sweetness and make onions more pleasant for consumption. [ABSTRACT FROM AUTHOR]

In vitro regenerated bulblets of Hyacinthus orientalis L., improved their size using MS medium containing different sucrose concentrations. The sucrose concentrations showed higher growth and better development of the bulblets on MS medium stored at 24 °C. Sucrose showed the highest performance rate at 9 % concentration for both small and large bulblets. Sucrose treatments showed positive effects of induction of bulb diameter, number of shoots per bulb, shoot length and bulb weight in the culture medium. [ABSTRACT FROM AUTHOR]

The aim of this study, conducted in the years 2010–2012, was to evaluate bolting and seed production of shallot depending on storage temperature of steckling bulbs with different diameters. The present study included 4 cultivars (‘Toto’, ‘Ambition F1’, ‘Bonilla F1’, and ‘Matador F1’) and one local population (‘U’). Bulbs with the following diameters: 20–30 mm, 31–40 mm, 41–50 mm, and 51–60 mm, were stored from the first 10-day period of November (2010 and 2011) until the end of March (2011 and 2012) at a temperature of 0–1 oC, 4–6 oC, and 8–10 oC. After they were planted in the field (the second 10-day period of April), observations of bolting were carried out, while the weight of seed umbels and seed yield were determined only for the cultivar ‘Toto’ and the population ‘U’. The storage temperature of steckling bulbs in the range of 4–6 oC and 8–10 oC was most conducive to bolting, in particular in plants grown from large bulbs with a diameter above 40 mm. In the cultivar ‘Toto’, plants from bulbs with a diameter above 40 mm and stored at a temperature of 4–6 oC were characterized by the highest weight of seed umbels. This had an effect on obtaining the highest seed yield (on average 1604.16-2300.7 g per 100 m2 of area). Shallot plants from the population ‘U’ grown from bulbs with a diameter of 20–30 mm were characterized by a distinctly lower percentage of bolting plants compared to the cultivars studied. For this reason, this population does not promise positive effects in shallot production for seed.

An experiment was conducted aiming to find out the seed production potentiality of 19 local and exotic onion cultivars. The analysis of variance showed significant differences among the genotypes for all characters except sprouting percentage, number of flowers per umbel and number of umbel per bulb. Maximum number of days to 50% bolting (52.67) was exhibited by the genotype G2 and minimum by G6 (27.00 days). The larger bulb size after harvest was obtained from G14 and G19 (18.11 g). Genotypes G4 and G11 required the maximum (16.66) and the minimum (9.00) days for 100% sprouting, respectively. The highest stalk length was found in the genotype G1 (67.23 cm) and the lowest in G8 (38.47 cm). Maximum number (5.75) of stalk was produced by the genotype G7 and minimum number (2.09) of stalk by the genotype G11. The genotype G1 produced the highest number of seeds per umbel (1395.92) and seed yield per plant (4.29 g). The lowest (0.45 g) seed yield per plant and maximum bulb weight was obtained by the genotype G8.

Safran Crocus sativus L. bilinen en eski kültür bitkilerinden biridir. Geçmişte baharat, boya ve tıbbi olarak büyük bir ekonomik öneme sahip olan bu bitki, önceleri Bolu, Tokat, Şanlıurfa, Adana, İzmir gibi illerde yetiştirilmesine rağmen zamanla önemini yitirmiş, dikim alanları giderek daralmış ve sadece Safranbolu’da birkaç üreticinin tarlası ile sınırlı kalmıştır. Son zamanlarda tekrar üzerinde durulan bu bitkinin üretiminin geliştirilmesinde en büyük engel tohumluk olarak kullanılan soğanların korm yetersizliğidir. Ankara Üniversitesi Tarla Bitkileri Bölümü deneme tarlasında yapılan bu araştırmada, soğanların çoğalmasında kültürel tedbir olarak dikim derinliğinin ve soğan boylarının safranın çoğalmasına etkisi araştırılmıştır. Farklı boylardaki safran soğanları 2002 yılında 20 x 10 cm aralıkla 5, 10 ve 15 cm derinliğinde dikilmiş ve 2004 yılında hasat edilmiştir. Dikim derinliği ve soğan boylarının hem safranın çiçeklenmesine, hem de yavru soğan oluşturmasına etkili olduğu bulunmuştur

The aim of this study, conducted in the years 2010-2012, was to evaluate bolting and seed production of shallot depending on storage temperature of steckling bulbs with different diameters. The present study included 4 cultivars ('Toto', 'Ambition F1', 'Bonilla F1', and 'Matador F1') and one local population ('U'). Bulbs with the following diameters: 20-30 mm, 31-40 mm, 41-50 mm, and 51-60 mm, were stored from the first 10-day period of November (2010 and 2011) until the end of March (2011 and 2012) at a temperature of 0-1 °C, 4-6 °C, and 8-10 °C. After they were planted in the field (the second 10-day period of April), observations of bolting were carried out, while the weight of seed umbels and seed yield were determined only for the cultivar 'Toto' and the population 'U'. The storage temperature of steckling bulbs in the range of 4-6 °C and 8-10 °C was most conducive to bolting, in particular in plants grown from large bulbs with a diameter above 40 mm. In the cultivar 'Toto', plants from bulbs with a diameter above 40 mm and stored at a temperature of 4-6 °C were characterized by the highest weight of seed umbels. This had an effect on obtaining the highest seed yield (on average 1604.16-2300.7 g per 100 m² of area). Shallot plants from the population 'U' grown from bulbs with a diameter of 20-30 mm were characterized by a distinctly lower percentage of bolting plants compared to the cultivars studied. For this reason, this population does not promise positive effects in shallot production for seed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two onion hybrids have differed significantly in their agronomic and spectroradiometric response. [•] The more productive hybrid Cometa presented no significant correlations between yield and VIs. [•] In the late growth stage, onion biomass and yield were highly correlated to nine VIs in Red Mech. [ABSTRACT FROM AUTHOR]

Agricultural communities in the semiarid regions of the world are constantly being affected by water scarcity, increased regulations restricting water use, strong competition for irrigation water with the urban sector, and severe drought periods. Conversely, the consumer demand for high-quality and nutritious foods is increasing rapidly. A 2-year field study evaluated growth, yield, and bulb quality in response to precision planting density and deficit irrigation of onion (Allium cepa L.) in southwest Texas. Seeds of short-day sweet onion cv. Texas Grano 1015Y were planted in the field on II Nov. 2007 and 30 Oct. 2008 at two planting densities (PDs), 397,000 (standard) and 484,000 (high) seeds/ha. Three irrigation rates using growth stage-specific crop coefficients and subsurface drip were imposed after plants were fully established, 100%, 75%, and 50% crop evapotranspiration rates (ETc). Total rainfall plus irrigation received for each irrigation rate were 594, 501, and 413 mm in 2008 and 662, 574, and 486 mm in 2009. In both seasons, there were consistent trends in growth, yield, and quality parameters. Leaf fresh weight was unaffected by PD but was reduced by deficit irrigation at 50% ETc. Although increasing planting density reduced the average bulb size by 12%, it increased the number of marketable bulbs by 21% to 33% and marketable yield by 7% to 14%. In contrast, deficit irrigation showed a trend to reduce both the number of bulbs and bulb size with yield reductions of 8% to 13% at 75% ETc and 19% to 27% at 50% ETc. Neither planting density nor deficit irrigation rate had a significant effect on soluble solids content, pungency, or quercetin contents. These results suggest that growers of short-day onions in semiarid regions could adjust PDs to target high-value bulb sizes. Implementing water-conserving practices (deficit irrigation at 75% ETc rate) would result in a decrease of high-value bulb grades and modest losses in yield but not flavor or nutritional components. [ABSTRACT FROM AUTHOR]

The experiment was conducted at horticulture farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh to study the influence of bulb size and different levels of GA3 on bulb and bulblets production of tuberose during the period of April 2006 to January 2007. The two factors experiment was laid out with Randomized Complete Block Design (RCBD) with 3 replications. Factor A: Three sizes of bulb, i.e. small (1-1.5 cm), medium (>1.5-2.0 cm) and large (>2.0-2.5 cm) and Factor B: Six levels of GA3 (0, 100,150, 200, 250 and 300 ppm). In case of bulb size, maximum weight of individual bulb (45.48 g), maximum number of bulblets plant-1 (14), and maximum yield of bulb (9.10 t ha-1) and bulblets (11.44 t ha-1) was recorded in large size bulb as compared to other sizes of bulb. The highest yield of bulb (8.76 t ha-1) and bulblets (12.14 t ha-1) was found in 300 ppm concentration GA3. [ABSTRACT FROM AUTHOR]

Different doses of paclobutrazol (PBZ) and different bulb sizes of onion were evaluated to determine their effect on growth and seed production of onion. Onion variety 'Taherpuri' with three-bulb sizes - small, medium and large - was used. Four doses of PBZ were 0 (control), 20, 40, and 80 mg l-1. The two-factor experiment was laid out in a randomized complete block design with three replications. Application of PBZ significantly reduced the plant height, tillers per bulb, leaves per plant and length of scape. However, in other parameters such as the number of flowers, umbels per bulb, umbel diameter, 1000-seed weight and seed yield, there were no significant influences of PBZ concentrations used (p < 0.05). On the contrary, plant height, number of leaves per plant, length of scape, effective fruits per umbel, percentage of fruit set, and seed yield were positively influenced by different bulb sizes of onion. Higher values were obtained for the above-mentioned parameters from the larger-sized bulbs and values were decreased as the bulb sizes decreased. The maximum seed yield was recorded in plants grown from the large-sized mother bulb. The interaction between the PBZ doses and bulb sizes were also significant for some variables while it was not significant for others. [ABSTRACT FROM AUTHOR]