Screening of Onion (Allium cepa L.) Genotypes for Waterlogging Tolerance

Onion production is severely affected by waterlogging conditions, which are created due to heavy rainfall. Hence, the identification of waterlogging-tolerant onion genotypes is crucial for increasing onion production. In the present study, 100 distinct onion genotypes were screened for waterlogging tolerance under artificial conditions by using the phenotypic approach in the monsoon season of 2017. Based on plant survival and recovery and changes in bulb weight, we identified 19 tolerant, 27 intermediate tolerant, and 54 highly sensitive onion genotypes. The tolerant genotypes exhibited higher plant survival and better recovery and bulb size, whereas sensitive genotypes exhibited higher plant mortality, poor recovery, and small bulb size under waterlogging conditions. Furthermore, a subset of 12 contrasting genotypes was selected for field trials during monsoon seasons 2018 and 2019. Results revealed that considerable variation in the morphological, physiological, and yield characteristics were observed across the genotypes under stress conditions. Waterlogging-tolerant genotypes, namely, Acc. 1666, Acc. 1622, W-355, W-208, KH-M-2, and RGP-5, exhibited higher plant height, leaf number, leaf area, leaf length, chlorophyll content, membrane stability index (MSI), pyruvic acid, antioxidant content, and bulb yield than sensitive genotypes under stress conditions. Furthermore, the principal component analysis biplot revealed a strong association of leaf number, leaf area, chlorophyll content, MSI, and bulb yield with tolerant genotypes under stress conditions. The study indicates that the waterlogging-tolerant onion genotypes with promising stress-adaptive traits can be used in plant breeding programs for developing waterlogging-tolerant onion varieties.

Influence of compost and irrigation systems on the growth indices and yield of onion (Allium cepa L.)

Field trial was conducted during the 2017 dry season from March to June at Bayero University, Kano and Birji village both in Sudan savannah to determine the effect of compost rates and irrigation intervals on the growth and yield of onion (Allium cepa L.) The treatments were conducted in five rates of compost (0 t ha-1, 5 t ha-1, 10 t ha-1,15 t ha -1 and 20 t ha-1) and three irrigation intervals (5, 10 and 15 days). The treatments were laid out in a split plot design and replicated three times. Irrigation intervals were assigned to the main plot while compost rates were assigned to the sub plot. The gross plot size was 1.5 m x 2.0 m (3.0 m2) consisting of 10 rows of 2 m length. Data on growth and yield parameters were collected, weighed and subjected to analysis of variance (ANOVA). Treatment means were separated using Student-Newman-Keuls Test. The result ssize was 1.5 m x 2.0 m (3.0 m2) consisting of 10 rows of 2 m length. Data on growth and yield parameters were collected, weighed and subjected to analysis of variance (ANOVA). Treatment means were separated using Student-Newman-Keuls Test. The result showed that compost rates and irrigation intervals had significant effect on cropgrowth rate, relative growth rate, net assimilation rate and cured bulb yield. Application of 10 t ha-1 of compost had the heaviest cured bulb yield. Interactions between compost rates and irrigation intervals were significant on all the measured parameters as well as the cured bulb yield of onion at both locations. The optimum rate of compost was 15 t ha1 at both locations, while that of irrigation intervals were 10 and 5 days for BUK and Birji village, respectively. Therefore, these levels were recommended to be used by farmers of the study areas.

Growth and Bulb Yield of Garlic as Influenced by Clove Size

Garlic is an important cash crop in many regions of Ethiopia. However, the yield of the crop is constrained by several factors. Among these, inappropriate clove size is one of the major agronomic practices that can decrease the yield of the crop. Hence, a field experiment was conducted during the 2020/21 main cropping season at Debre Berhan University, College of Agriculture and Natural Resource Sciences, demonstration and research site to evaluate the effect of clove size on growth and bulb yield of garlic (Allium sativum L.). The treatments consisted of five clove sizes: 1–1.49 g, 1.5–1.99 g, 2–2.50 g, 2.51–2.99 g, and 3–3.5 g. An improved variety “Tseday” was used as a planting material. The experiment was laid out as a randomized complete block design in a factorial arrangement and replicated for three times. The results revealed that clove size significantly influenced all growth and yield parameters of garlic. Planting of 3–3.5 g cloves reduced days to emergence by 11 and 6.33 days and days to maturity by 28.33 and 18.00 days, respectively, as compared to planting of 1–1.49 g and 2–2.5 g cloves. This treatment also increased total bulb yield by 25.88% and 15.58%, respectively, as compared to planting of 1–1.49 g and 2–2.5 g cloves. In addition, this treatment significantly increased most of the growth and bulb yield components. Hence, it can be concluded that planting of 3–3.5 g cloves could be recommended to enhance early emergence, good vegetative growth, and total bulb yield of garlic.

Genetic Variability and Association Among Bulb Yield and Yield Related Traits of Garlic (Allium sativum L.) Genotypes at Bishoftu Agricultural Research Center, Ethiopia

Garlic (Allium sativum L.) is the second most important Allium species next to onion (Allium cepa L. in the world and from Africa, Ethiopia is ranked second most garlic produce next to Egypt. It is one of the most important vegetable crops in Ethiopia and is used as a component of food, cash and has also a tremendous use in the formulation of local medicines. Among abiotic factors affecting garlic production and productivity using garlic genotype which is susceptible for different biotic and abiotic agents contributed huge yield loss in agriculture center. Therefore, this field experiment was conducted to assess the genetic variability in garlic genotypes, to determine association among traits and estimate the direct and indirect effects of traits on bulb yield. The field evaluation of 34 genotypes and 2 released varieties (G-HL and Chefe) was conducted in 6x6 Triple Lattice Design at Bishoftu Agricultural Research Center during January 2020 to May 2020. Results of analysis of variance revealed the presence of significant differences among genotypes for 18 traits. The variation observed among genotypes for bulb yield ranged from 43.80 to 147.20 kg ha-1. The six genotypes had mean performances higher than the highest performing check variety (G-HL=99.5Kg ha-1). Generally, the results of this study showed the presence of variations among genotypes for agro-morphology traits with a wide range of genetic distances that could allow selection and/or hybridization of genotypes after the results of this study are confirmed across locations and over the years.

Early Sucrose Degradation and the Dominant Sucrose Cleavage Pattern Influence Lycoris sprengeri Bulblet Regeneration In Vitro

Bulblet formation and development determine the quantitative and qualitative traits, respectively, of bulb yield for most flowering bulbs. For Lycoris species, however, the underlying molecular mechanism remains elusive. Here, clonal bulblets of Lycoris sprengeri (Ls) derived from the same probulb were used as explants to establish efficient and inefficient in vitro regeneration systems by adjusting the 6-benzyladenine (BA) concentrations in media. BA application did not change the biological processes among groups but led to earlier decreases in sucrose and total soluble sugar (TSS) contents. Correlation analyses showed that the BA treatments changed the interaction between carbohydrate and endogenous hormone contents during bulblet regeneration. We found that two sucrose degradation enzyme-related genes, cell wall invertase (CWIN) and sucrose synthase, exhibited exactly opposite expression patterns during the competence stage. In addition, the regeneration system that obtained more bulblets showed significantly higher expression of LsCWIN2 than those that obtained fewer bulblets. Our data demonstrate the essential role of BA in accelerating sucrose degradation and the selection of a dominant sucrose cleavage pattern at the competence stage of in vitro bulblet regeneration. We propose that a relatively active CWIN-catalyzed pathway at the competence stage might promote bulblet regeneration, thus influencing bulb yield.

Genetic Variability, Heritability, and Genetic Advance Estimates in Garlic (Allium sativum) from the Gamo Highlands of Southern Ethiopia

Genetic variability is the fundamental requirement for any plant breeding program to develop a superior cultivar. This study aimed to estimate the genetic variability and determine the correlation between the various quantitative characteristics of garlic accessions. The experiment was carried out in the Ezo-Otte area of the Chencha district in the Gamo highlands of southern Ethiopia and 28 garlic accessions were evaluated in a Randomized Complete Block Design with three replicates. Various morphological descriptors were measured to evaluate the variability and correlation coefficients. The analysis of variance showed a highly significant variation for all characters, which indicates greater variability in the accession. High and moderate heritability in broad sense estimates were obtained for the majority of the traits examined. Days to maturity (28.09), bulb weight (22.33), and bulb diameter (equatorial) (21.33) showed higher genetic advance. The maximum value of the genetic progress as a percentage of the mean was observed in bulb yield, clove weight, bulb diameter (equatorial), and number of leaves. In addition, bulb diameter (equatorial), clove weight, bulb weight, and plant height were observed to be highly hereditary coupled with high genetic advance as a percentage of the mean, suggesting that they can be improved by direct selection. Coefficient analysis has shown that maximum attention should be paid to bulb diameter (equatorial), the number of cloves, bulb diameter (equatorial), bulb weight, plant height, and leaf length, as these traits also correlate positively and significantly with bulb yield.

​Response of Plant Growth Regulator on Bulb Yield of Onion (Allium cepa L.)

Background: Maharashtra ranks first in onion (Allium cepa L.) production with a share of 28.32%. However, the productivity of onion is low as compared to other countries. In order to enhance onion productivity, new and innovative agri-inputs are being tried continuously like providing humic acid, fulvic acid, plant growth regulators (PGR), auxin/amino acid spray, seaweed extract, biofertilizers, sulphur application etc. PGRs are considered to be one of the novel inputs that can help in increasing the productivity of onion in India economically. Plant growth regulators are considered as a new generation of agrochemicals when added in small amounts, modify the growth of the plants usually by stimulation or modifying one part of natural growth regulatory system, thereby increasing the crop yield. Most of the research data available is based on biochemical, seaweeds etc. Almost negligible literature is available pertaining to a PGR made with formulation of Seaweed extract and Protein Hydrolysate. An attempt has been made in this research work to evaluate the effect of PGR formulated with seaweed extract and Protein Hydrolysate as major constituents on onion bulb yield through both foliar and drenching application. Methods: A field experiment for evaluating the effect of plant growth regulator (PGR) formulated by Research and Development Department, M/s Rashtriya Chemicals and Fertilizers Limited was conducted at Chilli and Vegetable Research Farm, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (MH). During the experiment, the effect of different concentration of PGR viz., 0.2%, 0.4%, 0.6% and 0.8% and 1.0%, 1.2%, 1.4% and 1.6% through foliar and drenching application, respectively were studied. Result: Statistically, significant results of plant growth regulator application on vegetative growth, yield and qualitative characters of onion crop were observed. Significantly, maximum bulb yield was observed in the treatment PGR @ 0.6% (255.41 kg/ha) through foliar application which is at par with the treatment PGR @ 1.4% (246.67 kg/ha) through soil drenching along with RDF. According to the results, the suitable PGR dose for studied characters of onion under prevailing conditions was 0.6% foliar spray and 1.4% soil drenching along with recommended dose of fertilizers.

Development of soil test crop response based fertilizer prescriptions through integrated plant nutrition system for aggregatum onion (Allium cepa L.) under drip fertigation

An insight into the balanced crop nutrition and efficient irrigation will be rewarding to attain profitable bulb yield of shallow-rooted and high nutrient requiring aggregatum onion. To develop fertilizer prescription equations(FPEs) for aggregatum onion under drip fertigation by encompassing the Soil Test Crop Response approach (STCR), a field experiment was conducted in Palaviduthi soil series with 15 treatments viz., Absolute control (T1), Blanket recommendation (60:60:30) + Farm Yard Manure (FYM) @ 12.5 t ha-1(T2), STCR based NPK fertilizer recommendation (STCR-NPK) for the targeted yield of 14 (T3),15 (T4),16 t ha-1 (T5), FYM @ 6.25 (T6), 12.5 t ha-1 (T7), STCR–NPK+FYM @ 12.5 t ha-1 for the targeted yield of 14 (T8),15 (T9),16 t ha-1 (T10), Biocompost @ 2.5 (T11), 5 t ha-1 (T12) and STCR–NPK+Biocompost @ 5 t ha-1 for the targeted yield of 14 (T13),15 (T14),16 t ha-1 (T15). The results revealed that T10 was more supercilious than others. The basic parameters were deliberated from the experimental data on total nutrient uptake, initial soil fertility status, applied fertilizer doses. The aggregatum onion (variety CO 4) required 0.43, 0.32, 0.45 Kg of N, P2O5, K2O to produce one quintal of bulb yield. The percent contribution of nutrients from soil and fertilizer was 14.01, 54.57 for N, 35.11,50.50 for P2O5 and 12.69, 70.12 for K2O, respectively. The contribution of N, P2O5, K2O from FYM and biocompost were 41.02, 16.23, 41.53 and 47.98, 15.87, 49.56 percent sequentially. Based on the above parameters, the fertilizer prescription equations were formulated for aggregatum onion under drip fertigation in Palaviduthi soil series.

Diagnostique de production de l’oignon dans la partie Septentrionale du Cameroun

Oignon (Allium cepa L.) est une culture maraîchère présentant un atout économique important pour les paysans Camerounais. Cette étude visait à faire un diagnostic de production de l’oignon dans la partie Septentrionale du Cameroun afin de développer des stratégies d’amélioration durable de cette filière. Une enquête a été menée pour déterminer le profil des acteurs de la filière oignon, les variétés cultivées, les techniques culturales ainsi que les contraintes de production. Les enquêtes s’étaient déroulées en 2017 auprès des acteurs de la filière oignon. L’échantillonnage était constitué de 60 personnes dans chacune des trois régions du Grand Nord Cameroun, soit un échantillonnage global de 180 personnes. Les résultats montrent que la plupart des acteurs sont des producteurs et sont 1,47 fois plus nombreux que les commerçants. 04 variétés d’oignon sont cultivées : Goudami, Chagari, Belami et violet de Galmi. La variété Goudami avait un rendement en bulbe élevé (10 à 35 t/ha), une durée de conservation des bulbes plus importante et est la plus cultivée. La quasi-totalité (69%) des producteurs utilise les engrais chimiques pour améliorer le rendement de cette culture. Ces informations serviront de base de données dans le programme de perfectionnement de la filière oignon au Cameroun. English title: Diagnosis of onion production in the Northern Part of Cameroon Onion (Allium cepa L.) is a market garden crop that is a major economic asset for Cameroonian farmers. This study aimed at diagnosing onion production in the Northern part of Cameroon in order to develop strategies for onion sustainable improvement. A survey was conducted to determine the actors profile relative to onion sector, varieties grown, crop techniques as well as production constraints. The surveys were conducted in 2017 among actors of onion sector. The sample consisted of 60 people in each of the three regions of Far North Cameroon, for an overall sample of 180 people. The results shown that most of the actors are producers, they are 1.47 folds greater than traders. Four onion varieties are grown in the Northern part of Cameroon: Goudami, Chagari, Belami and Galmi violet. The Goudami variety presents high bulb yield (10 to 35 t/ha) and longer bulb shelf life, and is the most widely cultivated. Almost all (69%) of the producers use chemical fertilizers to improve onion growth. This information will be used as a database to improve the performance of onion sector in Cameroon.