Watermelon Cultivation Research Articles

Preliminary Evaluation of Watermelon Liquid Waste as an Alternative Substrate for Microalgae Cultivation: A Circular Economy Approach to the Production of High-Value Secondary Products by Chlorella vulgaris, Scenedesmus sp., Arthrospira platensis, and Chlamydomonas pitschmanii

In Italy, watermelon cultivation spans 9510 hectares, with production levels largely influenced by seasonal market demand. As a result, surplus watermelon left unsold by September often remain in the fields, where they decompose naturally and go to waste. A chemical analysis of the watermelon liquid fraction waste (WW) indicates a high carbohydrate concentration, highlighting the potential for biotechnological valorization of this waste stream, converting it into lipids or exopolysaccharides (EPSs). This study investigates the feasibility of utilizing WW as an alternative growth substrate for microalgae, aligning with circular economy principles and advancing sustainable agricultural practices. By repurposing agricultural byproducts, this research supports biorefinery objectives, aiming to convert biomass into high-value secondary products, including biofuels, pigments, and nutraceuticals. Scenedesmus and Chlorella strains demonstrated promising growth and adaptability in WW, achieving biomass yields of 0.95 ± 0.07 g L−1 and 0.37 ± 0.02 g L−1, respectively, with a significant EPS production observed as medium gelation. Although lipid accumulation was limited in this case by the WW substrate, the lipid profiles of both strains were distinctively altered, notably lacking linolenic acid.

Survey on Incidence of Gummy Stem Blight on Watermelon (Citrullus lanatus) in Karnataka, India

Watermelon (Citrullus lanatus) is an important cucurbitaceous crop cultivated worldwide. The cultivation of watermelon and other species of the family Cucurbitaceae is severely affected by several diseases like anthracnose, Alternaria leaf spot, bacterial fruit blotch, powdery mildew and gummy stem blight. Among the diseases, gummy stem blight is an emerging and devastating disease caused by Didymella bryoniae producing a serious threat to the economics of production of cucurbits like watermelon. A roving survey was carried out in eight districts of Karnataka (Chamarajanagara, Chikkaballapura, Gulburga, Vijayapur, Bengaluru urban, Kolar, Mysuru and Yadgiri) from 2021 to 2023 to record the incidence of gummy stem blight (GSB) disease on watermelon. The survey data revealed that GSB disease was observed in all areas. The per cent disease index ranged from 29.6 to 51.2 per cent. The maximum mean per cent disease index of (51.2%),) Bengaluru urban district and the lowest was seen in the Mysuru district (29.6%) followed by Chikkaballapura district (31.0%). The pathogen associated with gummy stem blight disease was isolated and proved the pathogenicity of the isolate and fulfilled the Koch’s postulates.

Cost and returns of watermelon cultivation in Raigad district of Maharashtra: An economic analysis

Cost and returns of watermelon cultivation in Raigad district of Maharashtra: An economic analysis

Effect of mineral fertilizers on the yield and growth parameters of watermelon in Kazakhstan

Abstract The study aims to determine the optimal regimes of mineral fertilization for the yield of commercial watermelon fruits. The research goal is to analyze how fertilization regimes affect the growth parameters of this plant, such as weight per fruit and average fruit weight per plant. The research subjects are watermelon varieties, such as two Crimson Sweet varieties (including hybrid Producer Hollar) and Kholodok. The study involved a field survey on the territory of Zhana Tau, a farm located in the Aktobe area of the Republic of Kazakhstan. The experimental design encompassed the following fertilizer applications: Variant I – N30P40K60, Variant II – N60P60K120 and Variant III – N90P60K120. The study found that mineral fertilizers have a significant impact on the yield and growth parameters of watermelon fruits. After the application of N30P40K60, the weight per fruit was 8.13 kg for Crimson Sweet and 8.35 kg for Kholodok. The highest fruit weight indicator, 11.45 kg, was achieved when hybrid Producer Hollar was cultivated with N90P60K120. The highest yield (55.9 t/ha) was recorded when growing hybrid Producer Hollar with N90P60K120. The yield of the Crimson Sweet and Kholodok varieties, with the same level of fertilization, amounted to 49.6 t/ha and 51.2 t/ha, respectively. Correlation-regression analysis of the data on watermelon yield showed that this parameter tends to increase with the increase in the use of mineral fertilizers. Therefore, further research may focus on studying the influence of even higher levels of each macroelement and their combined effects on crop structure and fruit quality in watermelon cultivation.

Investigating Changes in the Soil Fungal Community Structure, Functions, and Network Stability with Prolonged Grafted Watermelon Cultivation

Investigating Changes in the Soil Fungal Community Structure, Functions, and Network Stability with Prolonged Grafted Watermelon Cultivation

Population Dynamics and Environmental Correlates of Insect Pests in Watermelon, Citrullus lanatus (T.)

The study was conducted in Kandavara village, Chikkaballapur district, during 2021, investigated the insect pest complex affecting watermelon, Citrullus lanatus (T) following standard crop management practices but without any insecticidal interventions to assess the natural occurrence of insect pests. Weekly observations were made from February to April (2021) employing various sampling methods to monitor key pests, including leaf miners, thrips, whiteflies, fruit flies, leaf-eating caterpillars, and pumpkin beetles. The study revealed that leaf miners, Liriomyza trifolii (Frick) were the first to appear, peaking in the 11th Standard Meteorological Week (SMW) with 6.45 leaf mines per five leaves. Thrips, Thrips palmi Karny and whiteflies, Bemisia tabaci (Gennadius) emerged during the vegetative stage, showing a significant positive correlation with maximum temperature. Fruit flies, Zeugodacus cucurbitae (Coquillett) caused the most significant damage during the fruiting stage, with a peak incidence of 14.92 per cent in the 15th SMW. The study highlighted that higher temperature had a positive correlation with pest populations, while rainfall had a negative correlation reducing the pest activity. These findings emphasize the importance of precise timing in pest management interventions to minimize crop losses and enhance the sustainability and productivity of watermelon cultivation in India.

Performance of Row Cover with Mulch on Early Sowing of Watermelon in Semi-Arid Region

The experiment was conducted during the months of January to March in the year 2023 at Department of Renewable Energy Engineering, Junagadh Agricultural University, Junagadh (Gujarat). A field experiment was conducted to assess the performance of mulch and row covers in early watermelon cultivation with the primary aim on strategically removing row covers days after sowing. Randomized Block Design was employed with featuring of three treatments (mulching without row cover, mulching with row cover for 30 days and mulching with row cover for 45 days). Various yield and yield attribute parameters were recorded and analysed. The research findings indicated that the removal of row covers 30 days after sowing significantly influenced main vine length (2.72 m), number of nodes per main vine (36.40), number of fruits plant-1 (2.53), yield plant-1 (4.21 kg) and yield ha-1 (62.32 t ha-1). Removal of row covers 30 days after sowing exhibited higher net returns (Rs. 4, 85, 419 ha-1) and higher benefit-cost ratio (4.52). Removal of row cover 45 days after sowing significantly reduced the watermelon yield. The results unveiled that mulching with a row cover aster 30 days of sowing is the optimal approach for increasing watermelon yield and net returns in early watermelon cultivation.

A Transcriptomic Analysis of Bottle Gourd-Type Rootstock Roots Identifies Novel Transcription Factors Responsive to Low Root Zone Temperature Stress.

The bottle gourd [Lagenaria siceraria (Molina) Standl.] is often utilized as a rootstock for watermelon grafting. This practice effectively mitigates the challenges associated with continuous cropping obstacles in watermelon cultivation. The lower ground temperature has a direct impact on the rootstocks' root development and nutrient absorption, ultimately leading to slower growth and even the onset of yellowing. However, the mechanisms underlying the bottle gourd's regulation of root growth in response to low root zone temperature (LRT) remain elusive. Understanding the dynamic response of bottle gourd roots to LRT stress is crucial for advancing research regarding its tolerance to low temperatures. In this study, we compared the physiological traits of bottle gourd roots under control and LRT treatments; root sample transcriptomic profiles were monitored after 0 h, 48 h and 72 h of LRT treatment. LRT stress increased the malondialdehyde (MDA) content, relative electrolyte permeability and reactive oxygen species (ROS) levels, especially H2O2 and O2-. Concurrently, LRT treatment enhanced the activities of antioxidant enzymes like superoxide dismutase (SOD) and peroxidase (POD). RNA-Seq analysis revealed the presence of 2507 and 1326 differentially expressed genes (DEGs) after 48 h and 72 h of LRT treatment, respectively. Notably, 174 and 271 transcription factors (TFs) were identified as DEGs compared to the 0 h control. We utilized quantitative real-time polymerase chain reaction (qRT-PCR) to confirm the expression patterns of DEGs belonging to the WRKY, NAC, bHLH, AP2/ERF and MYB families. Collectively, our study provides a robust foundation for the functional characterization of LRT-responsive TFs in bottle gourd roots. Furthermore, these insights may contribute to the enhancement in cold tolerance in bottle gourd-type rootstocks, thereby advancing molecular breeding efforts.

Quantitative Trait Loci Mapping and Comparative Transcriptome Analysis of Fruit Weight (FW) in Watermelon (Citrullus lanatus L.).

The watermelon (Citrullus lanatus L.) holds substantial economic value as a globally cultivated horticultural crop. However, the genetic architecture of watermelon fruit weight (FW) remains poorly understood. In this study, we used sh14-11 with small fruit and N14 with big fruit to construct 100 recombinant inbred lines (RILs). Based on whole-genome resequencing (WGR), 218,127 single nucleotide polymorphisms (SNPs) were detected to construct a high-quality genetic map. After quantitative trait loci (QTL) mapping, a candidate interval of 31-38 Mb on chromosome 2 was identified for FW. Simultaneously, the bulked segregant analysis (BSA) in the F2 population corroborated the identification of the same interval, encompassing the homologous gene linked to the known FW-related gene fas. Additionally, RNA-seq was carried out across 11 tissues from sh14-11 and N14, revealing expression profiles that identified 1695 new genes and corrected the annotation of 2941 genes. Subsequent differential expression analysis unveiled 8969 differentially expressed genes (DEGs), with 354 of these genes exhibiting significant differences across four key developmental stages. The integration of QTL mapping and differential expression analysis facilitated the identification of 14 FW-related genes, including annotated TGA and NAC transcription factors implicated in fruit development. This combined approach offers valuable insights into the genetic basis of FW, providing crucial resources for enhancing watermelon cultivation.

Determination of Total Phenols, Total Flavonoids and Antioxidant Activity of Watermelon Peel and Rind from Several Cultivation Areas in Indonesia

Background: Watermelon (Citrullus lanatus) consists of peel and rind (30-40% of total fruit weight), commonly discarded as waste. Nonetheless, several studies have shown the potential benefit of these watermelon parts. This study aimed to determine the correlation between the watermelon cultivation areas and their chemical composition, especially phenols and flavonoids. Watermelon peel and rind were obtained from Jember (WJ), Sragen (WS), Langkat (WL), Hulu Sungai Tengah (WHST) and Lombok Tengah (WLT). Methods: The total phenols and flavonoids were determined by using the colorimetric method. Furthermore, the antioxidant activity was determined by using DPPH and ABTS methods. Result: The highest total flavonoids, i.e. 41.86±1,65 mgQE/100 g watermelon, was observed in the WHST rind. While WL peel showed the highest total phenols, i.e. 3.97±0.02 mgGAE/g. The correlation analysis for all samples showed no significant relationship between the antioxidant activity and total flavonoids. However, a significant relationship was found between the DPPH-IC50 and total phenols with a correlation value of 0.47 (p less than 0.01) for both watermelon parts peel and rind. In addition, watermelon peel contains higher total flavonoids compared to rind. But, there was no significant difference in the total phenols between the watermelon peel and rind. To conclude, both watermelon peel and rind obtained from five cultivation areas showed antioxidant activities contributed by the phenolic compounds.

Thiamethoxam Residuality in Papaya Plant and Fruit (Carica papaya Linnaeus) Cultivated in Rotation with Watermelon (Citrullus lanatus)

There is evidence of the high use of the neonicotinoid insecticide thiamethoxam, in tropical crops, for its effectiveness in the control of soil and plant pests. The objective of this study was to know the residuality and concentration of thiamethoxam in the papaya agroecosystem, in the main papaya fruit producing zone in the central area of the Gulf of Mexico. It was carried out during a papaya growing cycle with watermelon rotation; the taking of samples was according to the technique established by the NOM -AA-103-1988 for leaves and for fruit the NMX -FF-041- 1996 by the method of quartering in papaya and watermelon, the samples were analyzed with a HPLC-UV, the data obtained were statistically analyzed by parametric and non-parametric Kruskal- Wallis tests. The presence of thiamethoxam was found in papaya and watermelon cultivation plants, the concentrations in papaya leaves reported a maximum value of 0.29 mg/kg, while for the leaves of the watermelon rotation fruit it was 0.15 mg/kg. In papaya fruit, thiamethoxam concentrations are within a range of 0.24 to 0.32 mg/kg. The concentrations and residuality of thiamethoxam mainly exceed the maximum tolerance and residuality limits of the EFSA and FAO.

Cutting-Edge of Genotyping by Sequencing (GBS) for Improving Drought and Salinity Stress Tolerance in Watermelon (Citrullus lanatus L.): A Review

AbstractGenotyping by sequencing (GBS) is a very helpful approach and one of the most useful techniques for examining and analysing the genetic variation of various lines and varieties. GBS technology was used to identify single nucleotide polymorphisms (SNPs) and assess genetic variation in several watermelon accessions. GBS application in watermelon breeding programs has recently become a popular technique among many breeders. Watermelon (Citrullus lanatus L.) is a warm-season crop that is widely cultivated for its delicious fruit. And it is one of the most economically significant crops in the world. However, watermelon cultivation is frequently hampered by abiotic stressors such as drought and salinity. Recently, there has been a growing body of research on the mechanisms that allow watermelon to tolerate these stresses and improve crop yield. Generally, cucurbits are beneficial to human health, they provide necessary minerals, fibre, and nutrient components. Therefore, this review demonstrates the cutting edge of using GBS technology to identify genetic design of several features in watermelon to improve abiotic stresses (drought and saline). The application of the GBS technique has provided a distinct advantage in watermelon breeding studies. Based on GBS approach, many new candidate genes in watermelon lines control a variety of traits including saline and drought tolerance, fruit rind color, disease tolerance, nutrient components, size, and fruit shape were discovered. Modern breeding techniques are being used to develop economically viable vegetable crops that will meet customer preferences and needs. Further research is needed to enhance watermelon production.

Impact of Photosynthetic Efficiency on Watermelon Cultivation in the Face of Drought

Water availability is a limiting factor for plant production, especially in Brazilian semi-arid regions. The main aim of the study was to investigate the physiological effects of drought during the fruiting stage of watermelon cultivation. A completely randomized block design with four replications and six treatments varied by the number of lateral drip tapes (1 or 2) and the duration of drought stress (0, 4, and 8 days) was used. The following parameters were evaluated: relative chlorophyll content, relative leaf water content, electrolyte leakage, CO2 assimilation (A), stomatal conductance (gs), internal CO2 concentration, leaf temperature, transpiration (E), water use efficiency (WUE), carboxylation efficiency (CE), yield, thickness, diameter, length, and fruit °brix, at 4 and 8 days of drought. Drought negatively affected photosynthesis, particularly in treatments with a single dripper and 4 days of drought, resulting in reductions of up to 60% in A, 68% in gs, 44% in E, 58% in WUE, and 59% in CE, but did not have a significant effect on watermelon yield after 4 or 8 days of irrigation. It was concluded that drought influences the physiological responses of watermelon plants, mainly in reducing photosynthesis, but does not drastically affect fruit productivity in short periods of stress.

OFF-SEASON AGRONOMIC PERFORMANCE OF THREE EXOTIC WATERMELON VARIETIES IN THE SOUTH-WESTERN REGION OF BANGLADESH

The watermelon [Citrullus lanatus (Thunb.)] - a herbaceous, annual, and monoecious fruit - belongs to the family Cucurbitaceae and is usually cultivated in Bangladesh during the period from February to April. However, they may be grown year-round, and off-season watermelon cultivation is more profitable than seasonal farming. The research was conducted at the Field Laboratory of Khulna University from August to December, 2021 to evaluate the off-season agronomic performance of the selected three watermelon varieties viz. Kanya, Black Super, and Tripti. The experiment investigated both the vegetative and reproductive growth of watermelon following a Randomized Complete Block Design with five replications. Kanya had the longest vines with the most leaves, and nodes followed by Black Super and Tripti. All the watermelon cultivars were found to be similar in producing male flowers, while Black Super and Kanya produced more female flowers, and Black Super also produced the highest fruit yield (6.37 t ha-1), which was statistically similar to Kanya (5.84 t ha-1) and the lowest yield was obtained from Tripti (3.69 t ha-1). Kanya performed better regarding fruit length (22.47 cm), fruit width (30.89 cm), and fruit weight (1.03 kg). Black Super scored the highest TSS (8.43) (Brix0) value, followed by Kanya (7.63) and Tripti (6.39). The amount of weight loss after the harvesting of fruits was less in Black Super, followed by Kanya and Tripti. Black Super had a longer recorded shelf life (28 days) than the other two varieties. The results of this study suggest that Black Super and Kanya can be grown during the off-season in the south-western region of Bangladesh.

Assessing the Economic Viability of Watermelon Cultivation in Haryana and Karnataka, India: A Comparative Analysis

Aims: To analyze the costs, returns and profitability of watermelon production in the study area. Place and Duration of Study: The study was carried out in Haryana and Karnataka state during the year 2021-22. Methodology: For the study, 120 farmers (60 farmers from each state) were selected from Haryana and Karnataka which are selected purposively. From Haryana state, Sonipat and Jhajjar districts and from Karnataka, Koppal and Chitradurga districts were selected purposively based on highest area under watermelon production. From each district two blocks were selected randomly. Further from each selected block two villages (15 farmers each) were selected. Results: Farmers of Karnataka investing more on seeds and plant protection chemicals (PPC) compared to farmers of Haryana. The cost of cultivation is higher in the Karnataka state (₹1,70,034.37/ha) compared to Haryana state (₹1,49,450.59/ha) farmers. The variation in cost of cultivation is due to Karnataka farmers were spending more on seeds, neem cake and PPC. The gross and net returns obtained per hectare was more in Karnataka state compared to Haryana state, because Karnataka has the suitable agro-climatic conditions for growing watermelon. Conclusion: The cost and return analysis revealed that watermelon production in the study area was profitable with returns per rupee of investment (B: C ratio) of 1:51 in Haryana and 1:75 in Karnataka.

Detection of vegetation cover change in the Southern region of Bangladesh using the Normalized Difference Vegetation Index (NDVI) and Climate Smart Agriculture (CSA) practices

Bangladesh is extremely vulnerable to climate change, and vegetation indices serve as sensitive indicators. Due to the impacts of climate change, the cropping intensity of Southern region of Bangladesh is very low. So, this study aimed to analyze the changes in vegetation cover over time using the Normalized Difference Vegetation Index (NDVI) and identify the use of Climate Smart Agriculture (CSA) technologies and the benefits of using such technologies. A questionnaire survey was carried out by purposive random sampling method to detect 120 farmers’ socioeconomic status, hazards faced by climate change, adopted climate smart agricultural practices and its benefits for assessing Adaptive Strategy Index (ASI) in Amtali upazila of Barguna district and Kalapara upazila of Patuakhali district. NDVI analysis of multi-spectral remote sensing data from 2012 and 2022 indicated the extent of sparse vegetation of Kalapara has increased. Western part of Amtali upazila, fallow areas have become lessened in 2022 (354.55 km2) compared to 2012 (368.78 km2) due to adopting different CSA practices. Saline-tolerant crop varieties, sunflowers, and watermelon cultivation were the highest ranked among the CSA practices, with 301, 300, and 296 ASI, respectively. Calculated weighted average of CSA practices indicated the reduction of production cost, increased family income (49.19%) and cropping intensity (51.67%), which impacts developed social bonding.

Distinctive Aspects of Early Open-Field Watermelon Production

This study emphasizes the economic significance of watermelon cultivation in the Republic of Serbia, introducing innovative techniques such as seedling production, grafting, mulching with black polyethylene film and low tunnels. Collectively, these methods contribute to earlier planting, improved crop development, and enhanced fruit quality. Grafting, particularly using Lagenaria siceraria and Cucurbita species, positively impacts yields and flowering. The incorporation of black polyethylene film aids in weed control, reduces herbicide usage, and minimizes labor inputs. Low tunnels, with transparent film covers, modify microclimates, allowing for earlier harvests. These integrated practices offer a sustainable approach to advancing watermelon cultivation techniques, potentially influencing agricultural practices on a global scale by promoting efficiency, yield optimization, and resource conservation.

Establishing optimal nutrient solution compositions for watermelon cultivation in open or closed soilless crops

Establishing optimal nutrient solution compositions for watermelon cultivation in open or closed soilless crops

Natural field diagnosis and molecular confirmation of fungal and bacterial watermelon pathogens in Bangladesh: A case study from the Natore and Sylhet districts.

The study investigated watermelon diseases characterized by contrasting climatic conditions in the Sylhet and Natore Districts of Bangladesh. Sylhet experiences lower temperatures and high rainfall, while Natore has higher temperatures and low rainfall. In these survey regions, 40 watermelon fields were selected, and 10 diseases were observed, including 4 fungal, 3 bacterial, 2 water mold, and 1 viral disease. The observed diseases were Anthracnose, Cercospora leaf spot, Fusarium wilt, Gummy stem blight, Downy mildew, Phytophthora fruit rot, Bacterial fruit blotch, Angular leaf spot, Yellow vine, and Watermelon mosaic disease. Molecular analysis was done in the Plant Pathology Lab at Sher-e-Bangla Agricultural University using the specific primers for fungal (ITS1/ITS4) and bacterial (27F/1492R) DNA regions and identified nine pathogen species, excluding the causal organism of the viral disease. The identified pathogens included Colletrotrichum orbiculare, Cercospora citrullina, Fusarium oxysporum, Stagonosporopsis cucurbitacearum, Pseudoperonospora cubensis, Phytophthora capsici, Acidovorax citrulli, Pseudomonas syringae, and Serratia marcescens. The sequencing of the identified pathogens revealed high homology (98.91-99.71%) with known sequences in the GenBank database. Phylogenetic analysis showed six clusters for fungal and water mold pathogen isolates and three for bacterial isolates where the percentages of replicate trees were 100% in all the cases. Among the identified diseases, the highest disease occurrence was caused by Fusarium wilt (47.5%) followed by Gummy stem blight (41.5%) in the Sylhet region and Angular leaf spot (37.5%) followed by Yellow vine (33%) in the Natore area. Fusarium wilt also has a high disease intensity, demonstrating its devastating impact on yield. This study highlights the influence of environmental conditions on disease incidence and underscores the need for tailored management strategies. These findings provide a foundation for developing targeted disease management practices for sustainable watermelon cultivation in Bangladesh.

Testing a Soil Moisture Sensor Based Irrigation Controller in both Laboratory and Field Conditions for Fargo Silty Clay Soils

Highlights A soil matric potential sensor-based irrigation system was tested in lab and field experiments. Soil matric potential and soil moisture levels for each threshold were determined for Fargo silty clay soil through lab experiment. Thresholds 5, 6, 7, and 8 at -35, -45, -55, and -70 kPa were tested through the field experiment for watermelon production. Abstract. Irrigation scheduling plays a pivotal role in water management. Conventional irrigation methods often struggle to maintain consistent moisture across fields due to uniform water application irrespective of field conditions and soil moisture levels. Automatic soil moisture sensors offer a solution by tailoring irrigation based on field conditions. These systems trigger irrigation when soil is too dry or skip it when moisture levels are sufficient. Hence, setting the right threshold value is key for sensor-based irrigation. This study involved laboratory testing of an irrigation controller, and determining soil matric potential and volumetric water content at various thresholds (1 to 9) for Fargo Silty Clay soil. Subsequently, a field experiment assessed its performance for a drip irrigation system at different thresholds (5, 6, 7, and 8) for watermelon cultivation, both with and without clear plastic mulch, in a randomized layout. Thresholds 5, 6, 7, and 8 (-35, -45, -55, and -70 kPa), along with no irrigation, were considered with one irrigation event daily. Results from laboratory and field tests underscore the controller’s efficacy in managing drip irrigation timing and duration. Notably, threshold 7 (-55 kPa) combined with clear plastic mulch emerged as the most optimal treatment, yielding the highest watermelon production of 129.6 tons/ha. Moreover, this approach delivered premium produce quality, but utilizing only 142.2 mm of irrigation water. This study emphasizes the role of precise irrigation scheduling. By integrating smart technology and thoughtful threshold setting, agricultural practices can be elevated, yielding abundant crops while conserving water and promoting sustainability. Keywords: Controller, Drip irrigation, Mulch, Sensor, Watermelon.