Cucumber Cultivation Research Articles

Cucumber: Breeding and Genomics

Cucumber (Cucumis sativus L.) is one of the most important vegetable crops grown worldwide for immature fruits. Several improved varieties with a number of economically important traits were developed through conventional breeding. The availability of draft genome sequences has facilitated the wide application of genomics tools in cucumber improvement in last two decades. C. sativus var. hardwickii widely distributed in the northern foothills of the Himalayas is the progenitor of the present-day cultivated cucumbers. A large number of commercially cultivated varieties and hybrids were developed through conventional breeding approaches. In hybrid breeding, gynoecious sex expression has been used widely for the development of more productive hybrids economically. Genetic inheritance and molecular characterization were done for a large number of traits including agro-morphological, quality, biotic and abiotic stress tolerance. Besides, candidate genes were also identified for the number of traits and later on validated through transformation and knock-out. Sex expression has been studied widely in this crop and cucumber serves as the model crop to study sex expression. A number of genes for sex expression and other economically important traits were characterized and cloned. Development of cucumber inbreds with multiple disease resistance, better quality and tolerance to abiotic stress tolerance are the major focus in future cucumber improvement programme.

Nanochelating-based fertilizers: Innovations for yield enhancement in hydroponic cultivation

The increasing human population has resulted in a rise in the use of chemical fertilizers to enhance crop efficiency and quality. However, the utilization of these fertilizers has led to significant environmental pollution and raised concerns, including the potential risk of cancer. Consequently, there is a growing need for innovative fertilizer formulations that reduce dependency on chemical fertilizers. Nanochelating, an advanced technology, offers a promising solution by synthesizing chelated nutrients with diameters smaller than 100 nm. These nanochelates have shown considerable effects on crop productivity, even at lower concentrations compared with traditional chemical fertilizers. In this hydroponic study, we investigated the effects of various concentrations of nanochelated fertilizers (NCF) using the standard formulation outlined by "Resh" (0.25×Resh, 0.5×Resh, 0.75×Resh, 1×Resh and 1.25×Resh) in the cultivation of tomato and cucumber. Control plants were treated with chemical fertilizers (CF). The NCF-treated plants exhibited improvements in fruit attributes and plant development. Notably, the addition of 0.5×Resh-NCF significantly enhanced vegetative growth, fruit quality, total soluble solids, fruit length, and diameter, and plant pigments. Cucumber and tomato plants treated with 0.5×Resh NCF, at half the strength of the CF treatment, displayed the highest yield, with tomatoes yielding approximately 2.02 times more and cucumbers yielding 3 times more than the CF treatment. CF-fed tomato and cucumber plants exhibited lower cell membrane stability and water content. Proline content, an indicator of plant stress, decreased in the NCF-treated plants but increased at the highest concentration. Furthermore, catalase and peroxidase activity increased in tomato and cucumber plants following NCF application. These findings underscore the potential of nanochelating-based fertilizers to enhance growth, productivity, and associated components while minimizing fertilizer usage in hydroponic greenhouses.

Effect of Silicon on the Fruit Quality and Disease Response to Gummy Stem Blight in Cucumber

Gumm y stem blight (GSB) caused by Stagonosporopsis cucurbitacearum is the most destructive fungal disease affecting cucumber (Cucumis sativus L.) production. In Thailand, cucumber is one of the most popularly marketed vegetables and the cultivation of cucumbers or Cucurbitaceae often face impact epidemics and insect infestation. Furthermore, global climatic or climate change affects crop production too, which increases the frequency and severity of disease and pest outbreaks. Silicon (Si) enhances plant resistance against insect pests and fungal, bacterial, and viral diseases although Si is not the only beneficial element for plants but also it does play an important role in improving plant health and increasing resistance against pests and diseases. Therefore, the aim of the study was to investigate the effect of Si-application at two levels i.e., 50 ppm, and 100 ppm on yield, yield components, aroma, Si-concentration and disease response of cucumber under greenhouse condition in a randomized complete block design with 4 replications. Results, when compared with control, depicted that the highest fruit weight, marketable yield, fruit length, fruit width, and pith length were found under 50 ppm Si. Moreover, higher Si-levels resulted in increased aroma in rind (exocarp) and increased percentage of Si-concentrations in rind (exocarp), leaves, and shoot. Further in this research, the response of Gummy stem blight disease (GSB) in cucumber was also investigated the response of. The taxonomic identification of Stagonosporopsis cucurbitacearum was confirmed based on the evidence from morpho-molecular analyses and the pathogenicity test was performed to confirm its potential pathogenicity. The results showed that the varying treatments of Si affects the disease development. The 50 ppm Si caused the lowest disease response on cucumber fruits. This study can be used as a guideline for modifying Si-fertilizer application inputs to plants to increase disease resistance and fruit quality.

Developing artificial mixed diets for larval culture of sea cucumber, Holthuria leucospilota, and their effects on the internal microbiota

During the seedlings culture of sea cucumbers including Holthuria leucospilota, natural microalgae are generally used as ideal food for the pelagic larvae of sea cucumbers, which lead to a strong demand for microalgae production. However, microalgae production is time-consuming and laborious and susceptible to pests and variable whether, and unstable supply of microalgae often results in culture failure of sea cucumber larvae. In this study, we tested the effect of three different diets on the growth, survival rate, and internal microbiota composition of sea cucumbers aiming to develop an artificial diet for H. leucospilota larvae. The results showed that the sea cucumber larvae fed with the mixed artificial diet (composed of Sargassum powder, chilled macroalgae solution, wall-breaking Chlorella powder, and yeast powder) had the most balanced growth rate, highest survival rate, and a higher α-diversity and abundance of Plesiocystis, Haloferula, and Firmicutes in body when they were compared to the larvae fed with the natural bait, Chaetoceros muelleri. However, the abundance of potential pathogenic bacteria, Francisella and Acinetobacter, was higher in the larvae fed with the natural bait. In conclusion, the mixed artificial diet was developed for H. leucospilota larval culture, which can be used as a good alternative to live microalga with cumbersome processes.

Impact of Aerated Drip Irrigation and Nitrogen Application on Soil Properties, Soil Bacterial Communities and Agronomic Traits of Cucumber in a Greenhouse System.

Root hypoxia stress and soil nutrient turnover have been related to reduced crop productivity. Aerated drip irrigation (ADI) can effectively enhance crop productivity and yield. However, the response of the soil bacterial community to different irrigation water dissolved oxygen (DO) concentrations remains elusive due to the extreme sensitivity of microorganisms to environmental variations. We investigated the effects of aerated irrigation with different concentrations of DO on soil properties and agronomic performance of cucumber, as well as the contribution of the bacterial community. We performed experiments on cucumber cultivation in Shouguang, China, including different irrigation methods (ADI: O2-10 and O3-20 mg L-1, non-aerated groundwater: O1-5 mg L-1) and nitrogen (N) application rates: 240 and 360 kg N ha-1. ADI (particularly O2) significantly improved soil properties, root growth, cucumber yields, and irrigation water use efficiency (IWUE), and appropriate DO concentrations reduced N fertilizer application and increased crop yields. Furthermore, these changes were associated with bacterial community diversity, aerobic bacteria abundance, and consolidated bacterial population stability within the network module. Environmental factors such as soil respiration rate (Rs), DO, and NO3--N have significant effects on bacterial communities. The FAPROTAX results demonstrated enhanced nitrification (Nitrospira) and aerobic nitrite oxidation by soil bacteria under ADI, promoting the accumulation of effective soil N and improved soil fertility and crop yield. Appropriate DO concentration is conducive to the involvement of soil bacterial communities in regulating soil properties and cucumber growth performance, which are vital for the sustainable development of facility agriculture.

Physicochemical Properties and Bacterial Diversity of Sediment in Sea Cucumber Culture Ponds under High Summer Temperatures

This study examined the effect of aquaculture management parameters on sea cucumbers in culture ponds during high summer temperatures. The physicochemical properties of 18 sediment samples from six sea cucumber culture ponds were assessed at a high temperature (HT) and the end of the high temperature (EHT) stages of summer. High-throughput sequencing was used to analyze the bacterial community composition and diversity of the sediment in the culture pond. The results showed that total nitrogen (TN), total carbon (TC), total organic carbon (TOC), ammonia nitrogen (NH4+), total sulfur (TS), sulfate (SO42−), and sulfide (S2−) contents were the lowest in the Geziling sediments at both stages, indicating a favorable sediment environment. The TN, TC, TOC, and NH4+ contents decreased significantly in the Wulei Island sediments during the EHT stage, indicating strong self-purification capacity. The TN, TC, TOC, NH4+, TS, SO42−, and S2− were higher in the Rushankou and Xiaohongcun sediments during both stages, indicating a worse sediment environment. Alpha diversity analysis revealed increased bacterial diversity in the sediments during the HT stage when compared to that during the EHT stage. Correlation analysis between bacterial diversity and the physicochemical properties of the TN sediments had the greatest impact on bacterial diversity, followed by TOC, TC, NH4+, TS, S2−, SO42−, and NO2− (in order). Our results suggest that the physicochemical properties (TC, TOC, TN, and NH4+) of the culture pond sediment can significantly influence bacterial community composition and diversity. Management measures for aquaculture, including desilting and monthly water change, could positively affect these physicochemical properties and the bacterial community structure of the sediment. These findings will provide a reference for healthier aquaculture practices of Apostichopus japonicus under high summer temperatures.

Determination of the pests and their natural enemies in a highland greenhouse cucumber cultivation in Antalya, Turkey

Determination of the pests and their natural enemies in a highland greenhouse cucumber cultivation in Antalya, Turkey

Using fermented mixture of macrophytes in the technology of compound feed for industrial cultivation of juvenile sea cucumber <i>Apostichopus japonicus</i>

Enzymatic hydrolysis of seaweed and seagrass (anfeltia Ahnfeltia tobuchiensis, laminaria Saccharina japonica, and eelgrass Zostera marina) is investigated. The enzyme preparation Viskoferm was the most effective for the mixture of these macrophytes, with high content of laminaria and eelgrass, under conditions of temperature 65 оC and pH 6.0. The hydrolysis in 16 hours reduced content of high-molecular polysaccharides and increased the portion of easily hydrolysable carbohydrates. Feeding of the sea cucumber juveniles by compound feeds with this fermented mixture of macrophytes had a positive effect on their physiological state; the food was easily digested by the animals and provided good gains. The average daily weight gain of juvenile sea cucumber in hatchery conditions had increased by 1.2 times in case of using the starter compound feed and by 1.5 times — for breeding with the productional compound feed.

Development of a Cucumber Transpiration Model Based on a Simplified Penman-Monteith Model in a Semi-closed Greenhouse

We aimed to develop a more accurate transpiration model for cucumber (Cucumis sativus L.) plants to optimize irrigation and nutrient usage in soilless greenhouse cultivation. Accurate modeling of transpiration in greenhouse-grown cucumbers is crucial for effective cultivation practices. Existing models have limitations that hinder their applicability. Therefore, this research focused on refining the modeling approach to address these limitations. To achieve this, a comprehensive methodology was employed. The actual transpiration rates of three cucumber plants were measured using a load cell, enabling crop fresh weight changes to be calculated. The transpiration model was developed by making specific corrections to the formula derived from the Penman-Monteith equation. In addition, the study investigated the relationship between transpiration rate and solar radiation (Rad) and vapor pressure deficit (VPD), identifying a nonlinear association between these variables. The transpiration model was adjusted to account for these nonlinear relationships and compensate for Rad and VPD. Comparative analysis between the actual and estimated transpiration rates demonstrated that the developed cucumber transpiration model reduced overestimation by 23.69%. Furthermore, the model exhibited higher coefficients of determination and root mean square error (RMSE) values than existing models, suggesting its superior accuracy in predicting transpiration rates. Implementing the transpiration model-based irrigation method demonstrated the potential for ∼21% nutrient savings compared with conventional irrigation practices. This finding highlights the practical applications of the developed model—accounting for a nonlinearity of Rad and VPD—in optimizing irrigation practices for greenhouse cucumber cultivation.

Green Waste from Cucumber (Cucumis sativus L.) Cultivation as a Source of Bioactive Flavonoids with Hypolipidemic Potential

Cucumber is an important agricultural crop that is cultivated under greenhouse conditions. Cucumber cultivation generates substantial quantities of green waste that require proper disposal. The lack of data on the chemical composition of cucumber greens and their biological activity emphasizes the necessity for research on useful products resulting from this widely available waste. Our examination of the flavonoid contents in the leaves and stems of 30 cucumber cultivars revealed 6 cultivars with high flavonoid contents. In addition, the cutting time did not cause negative effects, and we observed a positive effect with 0.05–0.10% organomineral fertilizer application on the flavonoid levels in the greens. Liquid chromatography–mass spectrometry detected 38 apigenin derivatives, including acylated and non-acylated cucumerins and C-, O-, and C,O-glycosides. Among these, 12 known flavonoids and 18 novel compounds were identified. The concentrations of these compounds in the six flavonoid extracts varied at 39.85–181.53 mg/g for the non-acylated flavones, 14.67–293.31 mg/g for the cucumerins, and 401.73–892.17 mg/g for the acylated flavones. Oral administration of the total flavonoid extracts (at a dosage of 100 g/kg/day) resulted in a hypolipidemic effect in hyperlipidemic hamsters, with subsequent normalization of their serum lipid profiles, malondialdehyde levels, and liver antioxidative enzyme activities. These results substantiate the lipid-lowering potential of cucumber waste extracts. Our investigation of the selected flavonoid activity showed that isovitexin-2′′-O-glucoside-6′′-O-p-coumarate (administered at 50 g/kg/day) had the highest hypolipidemic potency. These results can contribute to the practical use of cucumber green waste and the development of novel supplements for diseases linked to high-fat consumption.

Intelligent recognition and behavior tracking of sea cucumber infected with Vibrio alginolyticus based on machine vision

The outbreak of aggregative diseases in the process of sea cucumber cultivation has brought huge economic losses to aquaculture farmers. It is of positive significance to realize intelligent detection of abnormal behavior to avoid the outbreak of aggregative diseases. Therefore, this paper researches the approaches of intelligent recognition and behavior tracking of sea cucumbers. Fusing the Coordinated Attention and Bi-directional Feature Pyramid Network, the DT-YOLOv5 intelligent recognition model is proposed to enhance the representation ability and feature extraction ability. A multi-object behavior tracking approach is presented based on the automatic frame-matching coordinates, which can track multiple objects and calculate the volumes of exercise. The experimental results show that the precision, recall and AP50:95 are 99.43%, 98.91% and 84.89%, respectively. This research provides a theoretical support for the detection of abnormal behavior of aquatic animals during intensive aquaculture and has potential practical application value for protecting the welfare of sea cucumbers and improving the intelligence level of aquaculture.

Improving potential of reactive nitrogen and carbon footprint of intensified greenhouse cucumber-tomato production with optimized drip irrigation with nitrogen reduction strategies

Guaranteeing a robust supply of vegetables is a significant public welfare endeavor. However, the implementation of irrational water and fertilizer regimes in greenhouse vegetable fields (GVF) has resulted in adverse environmental impacts. Therefore, it is crucial to develop water and fertilizer regimes to maintain the productivity of greenhouse vegetables with less carbon (C) and reactive nitrogen (Nr) footprint. A four growing seasons experiment involving the cultivation of cucumbers and tomatoes was conducted in the suburbs of Beijing. The experiment comprised three treatments: flood irrigation with a conventional urea-N application (FN), drip fertigation with a conventional urea-N application (DN), and drip fertigation with a 50% reduction of urea-N application (DRN). The results showed that about 70% of annual N inputs in GVF were surplus, posing a high risk of loss. For the FN treatment, the N budget, Nr loss, Nr footprint per unit of vegetable yield (NrFY), Nr footprint per unit of net return (NrFR), greenhouse gas (GHG) emissions, C footprint per unit of vegetable yield (CFY), C footprint per unit of net return (CFR) were respectively quantified as follows: 1653 kg N ha−1 yr−1, 776 kg N ha−1 yr−1, 4.39 kg N t−1 yr−1, 24.48 kg N ¥10000−1 yr−1, 46548 kg CO2-eq ha−1 yr−1, 262.98 kg CO2-eq t−1 yr−1 and 1467.58 kg CO2-eq ¥10000−1 yr−1. Compared with FN, DN significantly reduced Nr loss (25%), NrFY (24%), NrFR (22%), GHG emissions (6%), CFY (4%), while it increased N surplus (9.7%) and produced lower farmers' net return (¥ 13486 ha−1 yr−1). Concurrently, DRN significantly reduced the N surplus, Nr loss, NrFY and NrFR by ∼35%, decreased the GHG emissions, CFY and CFR by ∼20%, and improved farmers' net return by ¥ 674 ha−1 yr−1 compared to FN treatment. Therefore, this study highlighted that an integrated water and fertilizer regulation strategy (drip irrigation replacing flood irrigation coupled with a 50% reduction in chemical N application) can simultaneously achieve environmental and economic benefits in the context of high N inputs. This contributes to the sustainable development of intensive vegetable cultivation systems.

Greenhouse Cultivation of Cucumber (Cucumis sativus L.) in Standard Soilless Media Amended with Biochar and Compost

Peat is one of the most commonly used substrates in soilless cultivation. However, peat mining produces a negative carbon footprint, which raises the need for alternative sustainable substrate media. To address this, we studied the impact of peat replacement with a combination of various biochars and cotton burr compost on the growth and yield of cucumber (Cucumis sativus L.), and nutrient concentration of media, plant leaf, and fruit in greenhouse conditions. Two experiments were conducted from Nov 2020 through Jan 2021 (Trial 1) and from Feb to Apr 2021 (Trial 2). The treatments were control (peat, vermiculite, and perlite at 2:1:1) and in the control peat was either fully replaced (hardwood biochar+compost, softwood biochar+compost, and hemp biochar+compost) or partially replaced up to 50% (v/v) (hardwood biochar+compost, softwood biochar+compost, and hemp biochar+compost). The control media was more acidic with lowest electrical conductivity than the other treatments. The leaf chlorophyll content and the photosynthetic assimilation rate varied among the treatments in both trials. The final dry shoot biomass was lowest in peat-dominated control treatment suggesting biochar-compost in the substrate media contributed in increased dry biomass of the cucumber plant. The total number of fruits per plant and total yield per plant was significantly increased in all the treatments with the highest in hardwood biochar+compost, compared with the control. The nutrient concentration of media, leaf, and fruit indicates that biochar-compost enhances the nutritional status of the media, which supplies essential nutrients to the plant leaf and fruit while growing in different substrate compositions. Our results suggest that the replacement of peat with full or partial proportions of biochar-compost can produce similar and, in some cases, even better growth, yield, and physiology in potted cucumber than in the unamended control treatment.

Defence-related components in cucumber susceptibility to target spot

Target spot is an important disease in cucumber culture. Due to differences in the susceptibility of cucumber cultivars to the disease, the objective was to evaluate the behavior of three cvs. in terms of leaf trichome density and biochemical variables in the interaction with the pathogen Corynespora cassiicola. The density of trichomes was evaluated on both sides of the leaves. The activity of peroxidase and polyphenol oxidase enzymes and the levels of free and bound phenolic compounds were evaluated one, three and five days after inoculation or not with the pathogen. The enzymatic activity was higher in the Safira cv., less susceptible to the disease, in relation to the Taiko and Soldier cvs. Inoculated plants showed higher peroxidase activity, showing that the response to infection was accompanied by the synthesis of this enzyme, and it increased with the days after inoculation. The levels of phenolic compounds varied according to the cvs. and as a function of time, with the highest levels in the Safira and Soldier cvs. Higher density of trichomes was found in the Safira cv., with no differences between Soldier and Taiko cvs. The adaxial side of the leaves had a greater number of trichomes than the abaxial side. No direct relationships were observed between biochemical and trichome variables and disease severity in cucumber cvs., since the Soldier cv., the most susceptible to the disease, did not differ in relation to 'Taiko' in enzymatic activities, free phenolic compounds and number of trichomes, including higher levels of bound phenolic compounds.

Response of soil microbial community diversity to continuous cucumber cropping in facilities along the Yellow River irrigation area.

Cucumber is an important cash crop; however, continuous cropping obstacles readily occur within the intensive production processes of facility horticulture. This study aimed to determine the effects of continuous cropping on soil quality and the microbial community in the rhizosphere soil of cucumbers. Rhizosphere soil of cucumber planted continuously for 4, 8, and 12 years was investigated, and soil that was not continuously planted was used as the control. Soil physicochemical properties, enzyme activity, microbial diversity, and richness were determined. The results showed that with the increase in continuous cropping years (0, 4, 8, and 12 years), soil total salt content continuously increased, while the pH value significantly decreased. Compared with the control, soil organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, and nitrate nitrogen contents increased significantly after 4 and 8 years of continuous cropping. Spearman correlation analysis showed that pH was negatively correlated with sucrase or sucrose and available phosphorus was positively correlated with alkaline phosphatase. Compared with the control, the diversity and abundance of bacterial and fungal communities in cucumber rhizosphere soil decreased after 4 and 12 years of continuous cropping. Continuous cropping led to a significant increase in the richness of the dominant phylum of cucumber rhizosphere soil. Principal coordinates analysis showed that, compared with the control, the soil microbial community structure was significantly separated after 4, 8, and 12 years of continuous cropping, and the microbial community structure was most similar after 4 and 8 years of continuous cropping. In addition, redundancy analysis showed that pH was the main driver of soil microbial dominance. In conclusion, continuous cropping of cucumber along the Yellow River irrigation area has led to the deterioration of soil nutrients and microbial communities in that region. This experiment provides a theoretical foundation for addressing the challenges associated with continuous cropping in cucumber cultivation.

Effect of Shading and Supplemental Lighting for Greenhouse Cultivation of Cucumber in Summer Season

Effect of Shading and Supplemental Lighting for Greenhouse Cultivation of Cucumber in Summer Season

Comparative Analysis of Gut Microbial Community Structure of Three Tropical Sea Cucumber Species

Based on 16S rRNA gene high-throughput sequencing technology, the microbial community structure in the gut of three tropical sea cucumber species, Holothuria atra, Stichopus chloronotus, and S. monotuberculatus, and their habitat sediments were analyzed. The OTUs in the gut contents of S. monotuberculatus, S. chloronotus, H. atra, and their sediments were 2489 ± 447, 1912 ± 235, 1628 ± 150, and 4162 ± 94, respectively. According to alpha diversity analysis (Ace, Chao1, Shannon, Simpson), the richness and diversity of microflora in the gut of all three sea cucumber species were significantly lower than that in sediments (p < 0.01). Anosim analysis showed that the intra-group differences were less than the inter-group differences (R > 0), and the microbial community composition of the sediment was distinctly different from those of three sea cucumber species (p < 0.05). UPGMA tree and Anosim analysis also revealed that the gut microbial communities of H. atra and S. chloronotus were more similar than that of S. monotuberculatus. Proteobacteria was the predominant phylum in all samples, and there was no significant difference in relative abundance among all groups. Actinobacteria was also a dominant phylum, and the relative abundance in S. chloronotus was significantly higher than that in other samples (p < 0.05). Potential probiotics and sequences related to Lactobacillus and Pseudomonas that may be developed for sea cucumber culture were also found in the study. It is speculated that the main reason for the difference in microbial communities between gut microbiota and environmental sediments may be the unique and quite different environment in the digestive tract of sea cucumbers. Whereas, the differences in gut microbiota among the three sea cucumber species were caused by selective feeding. These findings may provide basic data for tropical sea cucumber gut microflora studies and assist in the sea ranching and aquaculture development of the tropical sea cucumber species.

Cultivation of Cucumbers in Greenhouse Conditions: No Chemical Pollution

Cultivation of Cucumbers in Greenhouse Conditions: No Chemical Pollution

Cucumber abscisic acid 8'-hydroxylase Csyf2 regulates yellow flesh by modulating carotenoid biosynthesis.

Cucumber (Cucumis sativus L.) flesh is typically colorless or pale green. Flesh with yellow or orange pigment, determined mainly by carotenoid content and composition, is mostly found in semi-wild Xishuangbanna cucumber, which has a very narrow genetic background. Here, we identified a spontaneous cucumber mutant with yellow flesh (yf-343), which accumulated more β-cryptoxanthin and less lutein than regular cultivated European glasshouse-type cucumbers. Genetic analysis revealed that the yellow flesh phenotype was controlled by a single recessive gene. Through fine mapping and gene sequencing, we identified the candidate gene C. sativus yellow flesh 2 (Csyf2), encoding an abscisic acid (ABA) 8'-hydroxylase. Overexpression and RNAi-silencing of Csyf2 in cucumber hairy roots produced lower and higher ABA contents than in non-transgenic controls, respectively. Further, RNA-seq analysis suggested that genes related to ABA signal transduction were differentially expressed in fruit flesh between yf-343 and its wild type, BY, with white flesh. The carotenoid biosynthesis pathway was specifically enriched in fruit flesh at 30 days after pollination when yf-343 fruit flesh turns yellow. Our findings highlight a promising target for gene editing to increase carotenoid content, expanding our genetic resources for pigmented cucumber flesh breeding for improving the nutritional quality of cucumber.

Artificial spawning, hatchery and culture of the tropical sea cucumber (Holothuria leucospilota) using non-living food

Artificial breeding and farming of sea cucumber is considered as a sustainable way to meet market demand and minimize the pressure on wild populations. This study reports a method for large-scale artificial spawning, hatchery and culture of the tropical sea cucumber (Holothuria leucospilota). Spawning induction was performed by constant stimulation and dry shock. Both methods could obtain active and healthy fertilized eggs, but constant stimulation could get a greater oviposition amount of H. leucospilota. Among the six tested non-living food, the Spirulina platensis meal contains the highest contents of crude protein and total amino acids, and the Chlorella pyrenoidosa powder contains most abundant types of fatty acid. However, only the C. pyrenoidosa powder fed larvae could successfully develop to doliolaria stage. H. leucospilota fed C. pyrenoidosa powder had similar (P > 0.05) growth rate and survival rate but higher (P < 0.05) metamorphosis rate than that fed living Chaetoceros muelleri. The contents of crude protein and total amino acids of Saccharomyces cerevisiae yeast meal between that of C. muelleri and C. pyrenoidosa powder, but it failed to induce larval metamorphosis. The best diet scheme was mixing C. pyrenoidosa powder, S. cerevisiae yeast powder and sea mud followed by the ratio of 2:1:2 with the installment feeding mode, which reached the highest development rate of H. leucospilota. In summary, a simple and successful technology for large-scale artificial reproduction of H. leucospilota is set up in this study, which not only provide an excellent candidate for aquaculture in tropical regions, but also conducive to recover and reconstruct the wild population of sea cucumber.