Watermelon Production Research Articles

Evaluating the effect of honeybee pollination on production of watermelon (Citrullus lantatus), in Northern Ethiopia

Evaluating the effect of honeybee pollination on production of watermelon (Citrullus lantatus), in Northern Ethiopia

Salicylic acid-doped iron nano-biostimulants potentiate defense responses and suppress Fusarium wilt in watermelon

IntroductionChemo- and bio-genic metallic nanoparticles (NPs), as a novel nano-enabled strategy, have demonstrated a great potential in crop health management. ObjectiveThe current study aimed to explore the efficacy of advanced nanocomposites (NCs), integrating biogenic (bio) metallic NPs and plant immunity-regulating hormones, in crop disease control. MethodsIron (Fe) NPs were biosynthesized using cell-free supernatant of a Fe-resistant strains, Bacillus marisflavi ZJ-4. Further, salicylic acid-coated bio-FeNPs (SI) NCs were prepared via co-precipitation method under alkaline conditions. Both bio-FeNPs and SINCs were characterized using basic analytical techniques, including Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction analysis, and scanning/transmission electron microscopy. ResultsBio-FeNPs and SINCs had variable shapes with average sizes of 72.35 nm and 65.87 nm, respectively. Under greenhouse conditions, bio-FeNPs and SINCs improved the agronomic traits of the watermelon plants, and SINCs outperformed bio-FeNPs, providing the maximum growth promotion of 32.5%. Soil-drenching with bio-FeNPs and SINCs suppressed Fusarium oxysporum f. sp. niveum-caused Fusarium wilt in watermelon, and SINCs provided better protection than bio-FeNPs, through inhibiting the fungal invasive growth within host plants. SINCs improved the antioxidative capacity and primed a systemic acquired resistance (SAR) response via activating the salicylic acid signaling pathway genes. These findings indicate that SINCs can reduce the severity of Fusarium wilt in watermelon by modulating antioxidative capacity and potentiating SAR to restrict in planta fungal invasive growth. ConclusionThis study provides new insights into the potential of bio-FeNPs and SINCs as biostimulants and bioprotectants for growth promotion and Fusarium wilt suppression, ensuring sustainable watermelon production.

A Review of Watermelon Production and Price Trends from 2010 to 2021

Watermelons are primarily produced by eight states on over 100,000 acres each year (USDA-NASS, 2022). Most of the fruit (almost 80%) are cultivated in California, Florida, Georgia, and Texas with Florida leading in domestic production (USDA-ERS, 2020a). In 2019, Florida’s watermelon output accounted for 25.2% of total U.S. production, 24.7% of national watermelon acreage, and 29.6% of the overall crop value in the U.S (USDA-NASS, 2021). The value of Florida's watermelon output accounted for 13.2% of the state's total vegetable production (USDA-NASS, 2021). In 2021, the value of watermelon produced in the United States totaled $534 million, and production totaled 34.1 million cwt (USDA-NASS, 2022). These values show a decline in the value of watermelon produced and total production from 2020, by 7% and 1%, respectively (USDA-NASS, 2022).
 This report provides information on both seeded and seedless conventional watermelon acreage, volume, and pricing for California, Florida, Georgia, and Texas from 2010 through 2021. It is one of a series of EDIS publications that illustrate trends in Florida’s five most economically important specialty crops, excluding citrus: tomatoes, bell peppers, watermelons, sweet corn, and strawberries. This information will be useful to producers, extension agents, and others interested in trends concerning specialty crop commodities. It serves a single location where important information about specialty crop market and production trends can be found.

ENHANCED TOTAL PHENOLIC CONTENT EXTRACTION FROM CUCUMIS MELO L. (KULTIK) KERNEL BY DEEP EUTECTIC SOLVENT (DES)

Kernel of Cucumis melo L is a by-product produced from the water-melon production process. The phenolic compounds could be considered as a potential bioactive source for industrial applications. Therefore, the extraction of these compounds as much as possible will decrease valuable waste and could lead to produce value-added products. In the first part of this study, comparation of the effect of DESs and conventional solvent on total phenolic content (TPC) was performed. Some DESs had significantly better extraction yield than conventional solvent. Therefore, optimization of extraction conditions was performed by single factor experiment.
 Optimized parameters are molar ratio, type of HBA (hydrogen bond acceptor), addition of water content, extraction time and extraction temperature. From the results obtained, all these parameters were found to have an impact on TPC extraction yield. Also, it is noteworthy that the extraction yield using some selected parameters was on decrease after a certain extent. The best extraction parameter for Cucumis melo L. was found to be choline chloride as HBA, 1:4 molar ratio, %30 water addition, 500 extraction temperature and 30 min extraction time. This result confirms that kernel of Cucumis melo L. is a valuable ingredient due to its bioactive content, DESs could be a good alternative to conventional solvents and the industrial applications of DESs could be possible.

Economic Analysis of Cost of Production and Profitability of Watermelon in Thiruvallur District of Tamil Nadu in India

The current study, "Economic Analysis of Cost of Production and Profitability of Watermelon in Thiruvallur District of Tamil Nadu in India," was conducted from 2022 to 2023. 100 farmers from the study area were chosen at random to participate in the study. Analyzing the costs, returns, profitability, marketing, and production of watermelons in the study area were the study's primary goals. 100% of the farmers used drip irrigation to grow watermelons and sowed seeds during the rabi season. The majority of farmers in the study area employed inputs that were above what was advised for watermelon cultivation. Pre-structured interview schedules were used to collect the data. The survey indicated that marginal farmers, small and semi-medium farmers, and medium farmers, respectively, spent Rs 155691.8, Rs 154302.5, Rs 149897, and Rs 148131.5 per hectare on watermelon farming on average. On marginal, small, semi-medium, and medium farms, the input-output ratio concerning cost C was (1:1.36), (1:1.39), (1:1.41), and (1:1.44), respectively. The cost of production lowers as farm size grows.

Prediction of The Factors Affecting Watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) Yield Using Data Mining

The aim of this study was to evaluate the factors of affecting watermelon yield in Diyarbakır province. The data was obtained from surveying of 80 watermelon farmers in Diyarbakır province, Turkey by Simple Random Sampling Method using the Chi-square automatic interaction detector (EXHAUSTIVE CHAID) algorithm of the Data Mining Regression Tree methods. In the model created, the dependent variable was WY (watermelon yield), and the independent variables were determined as R (region), AF (age of farmer), EL (education level), CA (cultivation are), FD (fertilization date), FA (amount of fertilization), DS (date of spraying), AS (amount of spraying), NI (number of irrigation), IT (irrigation time), AN (anchor number), HT (harvest time). As a result of the study, the factors that significantly affect the yield of watermelon; AN, NI, HT, CA, R has been determined. An average of 4488.9 kg watermelon yield per decare was obtained and the number of hoes was the variable that most affected the watermelon yield. As a result in order to get a higher yield per unit area, watermelon producers should anchor number more than 4 times, irrigate 5 to 6 times at less than 2 hours, and apply fertilizer in May. In addition, Çermik, Eğil, Yenişehir and Bismil were determined as more suitable regions for watermelon production.

Watermelon as a potential nutritional horticultural crop: A comprehensive review

Watermelon possesses anticancer, anti-inflammatory and anti-oxidant properties due the phytochemicals like lycopene, vitamin C and polyphenolic material. Cardiovascular health conscious patients are consuming essential nutrient watermelon. Antioxidant property of watermelon plays an important role in coronary heart disease, cancer, diabetes, tension as well dehydration of body. The present review provides the information about different varieties that gain more production and keep in regulatory dietary source because of their nutritional values. It also supports to the selection of watermelon variety for more production from this ancient fruit. This information will encourage production and consumption of watermelon in worldwide.

Produção de mudas de melancia em diferentes substratos sob estresse salino

ABSTRACT Salt stress affects the production of watermelon (Citrullus lanatus) seedlings. However, substrates with alternative materials in their composition can mitigate the harmful effects on the formation of watermelon seedlings. Thus, the objective of the present study was to evaluate the emergence and production of watermelon seedlings grown in different substrates under salt stress. The research was conducted in an agricultural greenhouse belonging to the Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Redenção, Ceará, Brazil. The experimental design used was completely randomized in a split-plot scheme. The plots were five levels of electrical conductivity of irrigation water (ECw: 0.5, 1.5, 2.5, 3.5, and 4.5 dS m-1) and the subplots consisted of two formulations of substrates (SB1: sandy soil + sand + bovine manure; and SB2: sandy soil + sand + biochar; both in a 1:1:1 proportion on volume basis), with five repetitions of 25 seeds. The increase in the electrical conductivity of irrigation water from 1.5 dS m-1 reduces the percentage, speed index, and mean speed of emergence and increases the mean time of emergence of the watermelon crop. Substrate formulated with biochar reduces the time and increases the emergence indexes, besides enabling higher growth and biomass accumulation of watermelon seedlings. Salt stress reduces the growth, biomass, and quality of watermelon seedlings, but with less intensity with the addition of biochar.

Application of boron fertilizer and topping on female parent seed production of watermelon

High quality watermelon fruit can be influenced by the quality of the seeds planted. The purpose of this research was to obtain the dose of Boron fertilizer and topping on the seed production of watermelon female parent. The research was conducted from September 2021 to December 2021. This research was conducted using a factorial randomized block design consisting of 2 factors (Boron fertilizer dose and topping) which was repeated 4 times. Treatment of Boron Fertilizer consisted of 3 levels (0 kg.ha-1, 2 kg.ha-1, and 4 kg.ha-1). Topping treatment consists of 2 levels, without topping and using topping. The data were analyzed using ANOVA and LSD at 5%. The results showed that the dose of Boron fertilizer 2 kg.ha−1 gave the best effect on flowering age of male flower (20 DAP), flowering age of female flower (23 DAP), fruit weight (1.13 kg), seed weight per fruit (5.46 g), seed production per hectare (182.04 kg), and weight of 1000 seeds (39.50 g). The dose of Boron fertilizer 4 kg.ha−1 gave the best effect on seed germination (97%) and seed vigor (79%). Topping treatment did not affect all the parameters observed.

Chemical profiling of healthy and infected watermelon (Citrullus lanatus) affected by bacterial fruit blotch using gas chromatography–mass spectrometry

Acidovorax citrulli is the causative agent for bacterial fruit blotch in melons and watermelons. This disease causes several problems in the production and consumption of watermelon. The knowledge of the chemical profile of the interaction between the bacteria and the fruit can help in the adoption of measures to control this disease. Thus, this study investigated the volatile organic compounds (VOCs) in the fruit and seed of infected and healthy watermelon. In the present study, we used headspace-solid phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS). Chemometric analysis, Hierarchical cluster analysis (HCA) and Principal component analysis (PCA), was used and the results show that this technique associate to GC–MS can be used to differentiate healthy from infected samples. Phenylethyl alcohol was produced by bacteria cultivated in vitro as well as in infected fruits and healthy and infected seeds. Therefore, detection of some phenolic compounds (phenol, benzyl alcohol, p-cresol and 2-mehoxy-phenol), acetoin and 2,3-butanediol was observed in the infected samples, which indicated the presence of a possible defense mechanism against infection.

DETECTION OF Acidovorax citrulli IN WATERMELON SEEDLINGS IN HOPELCHÉN, CAMPECHE, MEXICO

In Mexico, there are no reports of the presence of Acidovorax citrulli, the causal agent of bacterial fruit blotch and seedling blight in cucurbits. The introduction of A. citrulli is a latent risk due to the importation of seeds and seedlings. Fruits and plants with typical symptoms of this disease have been observed in watermelon (Citrullus lanatus) production fields of small growers and commercial nurseries in the municipality of Hopelchén, Campeche. The objective was to detect A. citrulli by PCR in watermelon seedlings in a production area in Hopelchén, with the hypothesis that the bacterium is present in this municipality. In December 2018, 51 samples of nine watermelon varieties were collected from two seedling production nurseries. Each sample contained ten symptomatic seedlings ranging in age from 12 to 41 days. End-point PCR analysis with primers WFB1 and WFB2 indicated the presence of A. citrulli in 68.6 % of the samples; immuno-PCR results confirmed the presence of the bacterium in 80.9 % of these samples. Consensus 16S rRNA gene fragment sequences from eight samples aligned with 98 % similarity on average to A. citrulli sequences deposited in the GenBank-NCBI database. The dark, sunken, elongated lesions on cotyledonal leaves, as well as the black, spreading lesions from the margin to the base of true leaves observed on watermelon seedlings, were caused by A. citrulli. This study constitutes a new report of A. citrulli in Campeche, which should be considered to delimit and prevent the spread of the bacterium to other cucurbit-producing areas in Mexico.

Efficiency analysis of watermelon under plastic film mulching systems

Iran is the main watermelon producer in the world after China and Turkey. However, there is no practical information on which region, tillage and cultivation systems can achieve the most efficient watermelon production system in Iran. This study was conducted to assess the most efficient ways of watermelon production in three agroecosystems (cold, moderate, warm) of Iran using Data Envelopment Analysis. The data were collected from two tillage systems (reduced and conventional) and two groups of watermelon cultivations (conventional system and plastic film mulching system). Accordingly, twelve watermelon production systems were under the study including all inputs and outputs. Finally, an Analytical Hierarchy Process model was used to determine the best region and the best combination of cultivation and tillage systems for watermelon production. The technical and pure technical efficiencies of watermelon production systems were respectively 89%–100%. The Analytical Hierarchy Process model determined that the most efficient watermelon production systems were from combination of plastic film mulching system and reduced tillage in cold and moderate agroecosystem which reduced water and diesel fuel consumption by 500–2500 m3/ha followed by fertilizers by 100–150 kg/ha while efficiencies are enhanced by 20%–32%.

Fusarium oxysporum f. sp. niveum Pumilio 1 Regulates Virulence on Watermelon through Interacting with the ARP2/3 Complex and Binding to an A-Rich Motif in the 3' UTR of Diverse Transcripts.

Fusarium oxysporum f. sp. niveum (Fon), a soilborne phytopathogenic fungus, causes watermelon Fusarium wilt, resulting in serious yield losses worldwide. However, the underlying molecular mechanism of Fon virulence is largely unknown. The present study investigated the biological functions of six FonPUFs, encoding RNA binding Pumilio proteins, and especially explored the molecular mechanism of FonPUF1 in Fon virulence. A series of phenotypic analyses indicated that FonPUFs have distinct but diverse functions in vegetative growth, asexual reproduction, macroconidia morphology, spore germination, cell wall, or abiotic stress response of Fon. Notably, the deletion of FonPUF1 attenuates Fon virulence by impairing the invasive growth and colonization ability inside the watermelon plants. FonPUF1 possesses RNA binding activity, and its biochemical activity and virulence function depend on the RNA recognition motif or Pumilio domains. FonPUF1 associates with the actin-related protein 2/3 (ARP2/3) complex by interacting with FonARC18, which is also required for Fon virulence and plays an important role in regulating mitochondrial functions, such as ATP generation and reactive oxygen species production. Transcriptomic profiling of ΔFonPUF1 identified a set of putative FonPUF1-dependent virulence-related genes in Fon, possessing a novel A-rich binding motif in the 3' untranslated region (UTR), indicating that FonPUF1 participates in additional mechanisms critical for Fon virulence. These findings highlight the functions and molecular mechanism of FonPUFs in Fon virulence. IMPORTANCE Fusarium oxysporum is a devastating plant-pathogenic fungus that causes vascular wilt disease in many economically important crops, including watermelon, worldwide. F. oxysporum f. sp. nievum (Fon) causes serious yield loss in watermelon production. However, the molecular mechanism of Fusarium wilt development by Fon remains largely unknown. Here, we demonstrate that six putative Pumilio proteins-encoding genes (FonPUFs) differentially operate diverse basic biological processes, including stress response, and that FonPUF1 is required for Fon virulence. Notably, FonPUF1 possesses RNA binding activity and associates with the actin-related protein 2/3 complex to control mitochondrial functions. Furthermore, FonPUF1 coordinates the expression of a set of putative virulence-related genes in Fon by binding to a novel A-rich motif present in the 3' UTR of a diverse set of target mRNAs. Our study disentangles the previously unexplored molecular mechanism involved in regulating Fon virulence, providing a possibility for the development of novel strategies for disease management.

Grafting onto pumpkin alters the evolution of fruit sugar profile and increases fruit weight through invertase and sugar transporters in watermelon

Sweetness is an essential quality trait of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai), and it depends on both the concentration and composition of sugars. Grafting is a routine technique for watermelon production globally. However, it remains unknown whether rootstock alter the profiles of sugars in watermelon. To address this issue, we grafted watermelon seedlings onto a Cucurbita maxima × Cucurbita moschata rootstock, photosynthesis in leaves, contents of main carbohydrates, activities of invertase and sucrose synthase and expressions of invertase genes and sugar transporters in watermelon fruits were examined. Results showed that grafting could have delayed fruit ripening as fruits from grafted plants had a higher hexose/sucrose ratio (increased concentration of glucose and fructose and decreased concentration of sucrose) compared to fruits from self-grafted plants. These changes were associated with increased vacuolar invertase (VIN) activity. Meanwhile, a watermelon VIN gene (ClVIN2) and two CWIN genes (ClCWIN1 and ClCWIN4) were identified in updated watermelon genome, and ClVIN2 was upregulated accompanied by the elevated activity of VIN. In addition, rootstock grafted plants displayed improved net photosynthesis rate, increased expression of ClAGA2 (coding alkaline alpha-galactosidase), ClVST1 (coding vacuolar sugar transporter) and ClCWIN4 (coding cell wall invertase), and higher activity of cell wall invertase when compared with self-grafted plants, contributing to increased fruit weight. In summary, our results imply that invertase and related sugar transporters might play a role in sugar profiles and fruit weight differentiation observed during fruit maturity evolution.

First report of Watermelon crinkle leaf-associated virus 2 infecting watermelon (Citrullus lanatus) in Oklahoma.

Watermelon (Citrullus lanatus) is one of the major cucurbit crops in Oklahoma, which is grown on >1,200 acres. It contributes $16 million to the state's economy (Shrefler et al., 2017; NASS, 2022). During the 2021 growing season, virus-like symptoms on watermelon plants were observed in a grower's field in Blaine County, Oklahoma. These symptoms included mottling, crinkled leaf edges, and a unique yellow mosaic pattern (Fig. 1). Leaf tissue samples were randomly collected from nine plants and total RNA was extracted using Spectrum Plant Total RNA Kit (Sigma-Aldrich). Total RNA from one sample (named BL13) was subjected to high-throughput sequencing (HTS) on the NextSeq 500/550 High-Output kit v2.5 (Illumina, USA) at the genomic facility of Oklahoma State University. A total of 21,52,786 trimmed pair-end reads were assembled using CLC Genomics Workbench (v12.0.3) (Qiagen, Inc.) and subjected to BLASTn analysis. Of these, three contigs of 6,626 bp, 1,383 bp and 1,233 bp (average coverage 20,658X) showed 99% nucleotide (nt) sequence identity with RNA1 of a watermelon crinkle leaf-associated virus (WCLaV-2) isolate from Brazil (LC636073). The HTS data for BL13 samples also revealed three contigs of 263 pb, 567 bp and 1,066 bp that matched with cucumis melo crytpic virus isolate CmCV-HLI but was not confirmed by RT-PCR. The presence of WCLaV-2 in the BL13 sample was confirmed by RT-PCR using primers (RNA1-F: 5'-CAAAACGCCCATAAG AATAG-3'and RNA1-R: 5'- CTCCATTAATGAGAACTAGGAG-3') which amplified a 1.2 kb segment of the RNA1. The PCR product was confirmed on 1% agarose gel, cloned and three independent recombinant clones Sanger sequenced (Eurofins Genomics LLC, Louisville, KY, USA). The resulting consensus sequence (1.2 Kb) (ON453838) was subjected to a BLASTn search against the Genbank databases, resulting in 99.76% nt identity with WCLaV-2 RNA1 (Accession no. LC636073). Screening of the remaining eight symptomatic samples by RT-PCR revealed another positive sample (named BL7) for WCLaV-2. Consensus nt sequence (1.2 Kb) analysis for the virus isolate from the BL7 sample (Accession no. ON453839) shared 99.84% nt identities with WCLaV-2 RNA1 (LC636073). Total RNA from BL13 and BL7 samples, as well as the remaining seven samples, were tested against three major potyviruses (PRSV-W, WMV, and ZYMV) by multiplex RT-PCR (Rajbanshi & Ali, 2019). Both BL13 and BL7 samples were negative to all three potyviruses but the other eight samples were positive to one or two of the potyviruses. WCLaV-2 is a negative-sense ssRNA virus (family Phenuiviridae) and has been recently reported from watermelon in China (Xin et al., 2017) and Brazil (Maeda et al. 2022). In the United States, it has been reported from Florida (Hendrick et al., 2021), Georgia (Adeleke et al., 2022), and Texas (Hernandez et al., 2021). The mode of transmission of WCLaV-2 and its direct effect on watermelon fruit is not known (Xin et al., 2017; Maeda et al., 2022). Our results report for the first time the occurrence of WCLaV-2 infecting watermelon naturally in Oklahoma and show a further potential threat to watermelon production in the State. Further studies are needed to determine the incidence of WCLaV-2 in other counties of Oklahoma.

Volatile Aroma Compounds of Gavina® Watermelon (Citrullus Lanatus L.) Dietary Fibers to Increase Food Sustainability

To deal with climate emergency and reduce environmental impact, agro-industrial wastes are gradually gaining interest and are being used for new products and applications. The large production of watermelons represents an opportunity because of the many byproducts that can be transformed into innovative and valuable foodstuffs. In this study, we examined the lycopene-rich whole dietary fiber (WDF) obtained from the watermelon pomace of a peculiar cultivar, Gavina® (Oristano, Italy) a seedless fruit from Sardinia (Italy). The volatile chemical composition of the WDF was investigated using Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS). The aim was to follow the evolution of the Volatile Organic Compounds (VOCs) fraction during storage and verify its stability over time. Since watermelon is an excellent source of carotenoids, their byproducts were the most abundant VOCs of the freshly prepared samples, but their overall abundance decreased significantly during storage. The opposite trend was observed for acids and aldehydes, whose increase over time is related to amino acid degradation. Freshly prepared WDF can be used in the food industry as an antioxidant-rich dietary fiber that imparts a characteristic and pleasant aroma. Over time, its aroma profile and carotenoid content change considerably, reducing its health properties and limiting its potential application as a natural flavor.

Rootstocks Comparison in Grafted Watermelon under Water Deficit: Effects on the Fruit Quality and Yield.

Drought is widely recognized as one of the most significant agricultural constraints worldwide. A strategy to avoid the adverse effects of drought on crops is to cultivate high-yielding varieties by grafting them onto drought-tolerant rootstocks with a differentiated root system. Thus, the objective of this study was to evaluate fruit yield and quality, root system architecture, and water productivity of watermelon grafted onto Lagenaria siceraria rootstocks. To do so, a commercial watermelon cultivar "Santa Amelia" [Citrullus lanatus (Thunb.)] was grafted onto five L. siceraria rootstocks: 'Illapel', 'Osorno', 'BG-48', 'GC', and 'Philippines', which were grown under three irrigation treatments (100%, 75%, and 50% of evapotranspiration). The comparison of the L. siceraria rootstocks in the irrigation treatments demonstrated no significant effect on watermelon fruit quality parameters. The rootstocks 'Illapel', 'Osorno', and 'GC' significantly improved the fruit number and yield (total fruit weight) under water deficit. Similarly, 'Illapel', 'Osorno', and 'GC' consistently showed statistical differences for root system architecture traits compared to 'BG-48' and 'Philippines'. Based on these results, we concluded that the used L. siceraria rootstocks did not affect the fruit yield and quality of grafted watermelon under water deficit. This study may help adjust the amount of applied water for watermelon production where L. siceraria rootstocks are utilized.

The Influence of Climate Variability on the Watermelon Production in Zanzibar

Climate change and variability, has embarked societies in Zanzibar to rely on horticulture (i.e. watermelon production) as an adaptive measure due to an unpromising situation of commonly used agricultural yields. Currently, there is either no or scant information that describes the influence of climate changes and variability to watermelon production in Zanzibar. Thus, this study aimed to determine the influence of climate variability on the quantity of watermelon production in Zanzibar. The study used both primary and secondary datasets, which include the anecdotal information collected from interviewers’ responses from four districts of Unguja and Pemba, and climate parameters (rainfall, maximum and minimum temperature (Tmax and Tmin) acquired from Tanzania Meteorological Authority (TMA) at Zanzibar offices. Pearson correlation was used for analyzing the association between watermelon production and climate parameters, while paired t-test was applied to show the significance of the mean differences of watermelon and climate parameters for two periods of 2014-2017 and 2018-2021, respectively. Percentage changes were used to feature the extent to which the two investigated parameters affect each other. The anecdotal responses were sorted, calculated in monthly and seasonal averages, plotted and then analyzed. Results have shown a strong correlation (r = 0.8 at p ≤ 0.02, and r = 0.7) between watermelon production, Tmax and rainfall during OND, especially in Unguja, as well as Tmin during JJA (i.e. r = - 0.8 at p ≤ 0.02) in Pemba. Besides, results have shown the existence of significant differences between the means of watermelon production and climate parameter for the two stated periods, indicating that the climate parameters highly affects the watermelon production by either enhancing or declining the yields by 69% - 162% and 17% - 77%, respectively. Moreover, results have shown that respondents were aware that excess temperature intensity during dry periods can lead to high production costs due number of soil and other environmental factors. Besides the results have shown that OND seasonal rainfall and MAM Tmax had good association with watermelon production in Unguja while JJA Tmin declined the production in Pemba. Thus, the study concludes that seasonal variability of climate parameter has a significant influence on the watermelon production. The study calls for more studies on factors affecting watermelon production (e.g. soil characteristics, pest sides and manure), and recommends for climate based decision making on rain fed agricultural yields and routine monitoring of weather information.

Effect of Different Rates, Application Timing, and Combination of Nonfumigant Nematicides in Control of Meloidogyne incognita in Watermelon

The use of plasticulture systems, which consist of raised beds, plastic mulch, and drip irrigation, for watermelon production has increased in the Southern United States in recent decades. The root-knot nematode (RKN), Meloidogyne incognita, is a significant pathogen of watermelon production in plasticulture systems and can cause varying levels of yield loss depending on the nematode population density if not properly controlled. A few new nonfumigant nematicides (fluensulfone, fluazaindolizine, and fluopyram) have emerged in the last decade to help manage RKNs. A 2-year field study was conducted to examine the impact of different rates, application timing (i.e., days before transplanting, at transplanting, and days after transplanting), and combinations of these new nematicides and an older one (oxamyl) in control of RKN in watermelon cultivar Fascination. The nematicide treatments, except for a single-time application of oxamyl in 2019 and 2020, significantly reduced root galling compared with the untreated check. Similarly, all treatments, except a single application of oxamyl in 2020, resulted in a lower soil population level of M. incognita than the untreated check. All nematicide treatments, except a single application of fluensulfone and a two-time application of fluopyram at a half-recommended rate, increased fruit yields when compared with the untreated check. Overall, the drip application of new chemistries, known as 3-F nematicides, has been shown to be a useful option for RKN management in watermelon. At-planting application of fluazaindolizine or fluopyram and two-time applications of oxamyl based on the manufacturer's recommended rate show potential to prevent crop loss.

Analyses of energy use and greenhouse gas emissions (GHG) in watermelon production

Analyses of energy use and greenhouse gas emissions (GHG) in watermelon production