Watermelon Fruit Research Articles

Identification and Characterization of Fusarium Species Causing Watermelon Fruit Rot in Northern Thailand.

Fruit rot caused by phytopathogenic fungi is one of the major diseases affecting watermelons (Citrullus lanatus) around the world, which can result in unmarketable fruits and significant economic losses. Fruit rot was observed on watermelons throughout the postharvest storage periods in Phayao Province, northern Thailand in 2022. For the present study, a total of ten fungal isolates were isolated from the rot lesions of watermelons. All obtained fungal isolates were then characterized in terms of their pathogenicity. The results indicated that only four fungal isolates caused rot disease with similar symptoms during the postharvest storage period. Based on their morphological characteristics, these four fungal isolates were identified as belonging to the genus Fusarium. Using multi-gene phylogenetic analyses with a combination of the translation elongation factor 1-alpha (tef-1), calmodulin (cam), and RNA polymerase second largest subunit (rpb2) genes, the fungal isolates were subsequently identified as Fusarium compactum and F. paranaense. Taken together, the results of this study indicate that F. compactum and F. paranaense cause fruit rot disease in watermelons. To the best of our knowledge, this is the first study to report F. compactum and F. paranaense as novel pathogens of watermelon fruit rot both in Thailand and elsewhere in the world.

Transcriptome Analysis Reveals the Genes Related to Water-Melon Fruit Expansion under Low-Light Stress

Watermelon is one of people's favorite fruits globally. Fruit size is one of the important characteristics of fruit quality. Low light can seriously affect fruit development, but there have been no reports concerning molecular mechanism analysis in watermelons involved in fruit expansion under low-light stress. To understand this mechanism, the comparative transcriptomic file of watermelon fruit flesh at four different developmental stages under different light levels was studied. The results showed that the fruit size and content of soluble sugar and amino acids at low-light stress significantly decreased compared to the control. In addition, 0-15 DAP was the rapid expansion period of watermelon fruit affected by shading. In total, 8837 differentially expressed genes (DEGs) were identified and 55 DEGs were found to play a role in the four different early fruit development stages. We also found that genes related to oxidation-reduction, secondary metabolites, carbohydrate and amino acid metabolism and transcriptional regulation played a key role in watermelon fruit expansion under low-light stress. This study provides a foundation to investigate the functions of low-light stress-responsive genes and the molecular mechanism of the effects of low-light stress on watermelon fruit expansion.

Multi-omics integration to explore the molecular insight into the volatile organic compounds in watermelon

A range of volatile organic compounds played an important role in the formation of watermelon fruit aroma, while due to the low content and difficulty in detection, it is often neglected in watermelon breeding programs, resulting in a decline in fruit flavor. VOCs in the flesh of 194 watermelon accessions and seven cultivars at four developmental stages were determined by SPME-GC–MS. Ten metabolites with significant differences in the natural population and positive accumulation during fruit development are considered to be the key metabolite related to watermelon fruit aroma. And the link between metabolite and, flesh color and sugar content by correlation analysis was established. The results of the genome-wide association study showed that (5E)-6,10-dimethylundeca-5,9-dien-2-one, and 1-(4-methylphenyl) ethanone were colocalized with watermelon flesh color on chromosome 4, which may be regulated by LCYB and CCD. (E)-4-(2,6,6-trimethylcyclohexen-1-yl)but-3-en-2-one is the VOC produced by the cleavage of carotenoids, which has a positive correlation with the sugar content of the fruit, and the candidate gene Cla97C05G092490 on chromosome 5 may interact with PSY to influence the accumulation of this metabolite. In addition, Cla97C02G049790 (enol reductase), Cla97C03G051490 (omega-3 fatty acid desaturase gene), LOX, and ADH may play important roles in the synthesis of fatty acids and their derived VOCs. Taken together, our findings provide molecular insights into the accumulation and natural variation of VOCs in watermelon, and give data support for breeding watermelon cultivars with better flavor.

Levels of elements in selected food substances that support usage in the management and treatment of erectile dysfunction.

The use of fruits and vegetables for the management and treatment of erectile dysfunction has gained popularity due to the cheaper cost, accessibility and perceived absence of side effects. Much of the work done on plant-based aphrodisiacs has focused on the phytochemistry of secondary metabolites. This work sought to analyze selected fruits and vegetables that are commonly used in the management of erectile dysfunction in Ghana and quantify the levels of some micro- and macro-elements necessary for good penile health in order to determine the usefulness or otherwise of the selected produce. Energy-dispersive X-ray fluorescence spectroscopy was used to detect and quantify the levels of potassium (K), calcium (Ca), selenium (Se), magnesium (Mg), iron (Fe), and zinc (Zn) in carrot roots, cucumber fruit, garlic bulb, ginger rhizome, nutmeg fruit, sweet potato tuber, tiger nut tuber and watermelon fruit. The analysis revealed the presence of K, Ca, Mg, Fe and Zn. Levels of Se were below detection. The concentration of K was the highest in each of the food substances. However, in terms of recommended daily allowance, Mg had the highest contribution. Cucumber fruit and the rind of watermelon fruit had the highest levels of micro- and macro-elements implicated in erectile dysfunction. The potential use of these foods to treat and manage erectile dysfunction may not only be due to the presence of phytochemicals alone but also the presence of significant levels of micro- and macro-elements required for good penile health.

Development of fruit beverages with coconut water: Physicochemical characterization, antioxidant potential, and sensory properties

AbstractFruit beverages blends have been consumed for the balance between nutrients and flavor. The coconut water to replace water is a more natural solution and an option for blending in the fruit beverages. The present study aimed to develop fruit beverages using coconut water as a base, guava, watermelon, and was added apple juice as natural sweetener. Experimental design was used for the development of beverages, considering a factorial design 22, followed by the physicochemical and sensory analysis. The guava fruit was highlighted on antioxidant capacity results compared with the watermelon fruit, in the 2,2‐diphenyl‐1‐picrylhydrazyl (86.0 ± 2.5 and 11.7 ± 4.5% of reduction, respectively) and in the 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (31.7 ± 0.0 μmol trolox/g 12.8 ± 1.6 μmol trolox/g, respectively). The physicochemical results of the blends revealed that the beverages with guava (0.5 ± 0.0%) are more acidic than those with watermelon (0.2 ± 0.0%), indicating the impact of the intrinsic characteristics of each fruit in the final composition. According to the results of the sensory analysis and response surface methodology, verified the potential optimized formulas contain in their composition 40 g of fruit, 30 g of coconut water, and 30 g of apple juice per 100 mL of beverage, this composition affected the sensory acceptance of the beverages. Our findings indicated the fruit beverages with coconut water have functional attributes, sensory acceptance and can be used as one more option for beverages category.

Genetic mapping of a single nuclear locus determines the white flesh color in watermelon (Citrullus lanatus L.).

Flesh color is an important trait in watermelon (Citrullus lanatus L.). Several flesh color genes have been identified in watermelon; however, the inheritance of and the molecular basis underlying the white flesh trait remain largely unknown. In this study, segregation populations were constructed by crossing the canary yellow flesh line HSH-F with the white flesh line Sanbai to fine-map the white flesh gene in watermelon. Genetic analysis indicated that the white flesh trait is controlled by a single recessive locus, termed Clwf2. Map-based cloning delimited the Clwf2 locus to a 132.3-kb region on chromosome 6. The candidate region contains 13 putative genes, and four of them-Cla97C06G121860, Cla97C06G121880, Cla97C06G121890, and Cla97C06G121900-were significantly downregulated in the white flesh compared to the canary yellow flesh watermelon fruits. The Cla97C06G121890 gene, which encodes a tetratricopeptide repeat protein, showed almost no expression in the white flesh fruit before maturity, whereas it had a very high expression in the canary yellow flesh fruit at 18 days after pollination. Transmission electron microscopy revealed rounded and regularly shaped chromoplasts in both the canary yellow and white flesh fruits. Further quantitative real-time PCR analysis showed that the expression levels of several key plastid division genes and almost the entire carotenoid biosynthesis pathway genes were downregulated in the white flesh compared to the canary yellow flesh fruits. This study suggests that the proliferation inhibition of chromoplasts and downregulation of the CBP genes block the accumulation of carotenoids in watermelon and lead to white flesh. These findings advance and extend the understanding of the molecular mechanisms underlying white flesh trait formation and carotenoid biosynthesis in watermelon.

The Use of Different Modes of Transportation Affects the Chemical Qualities of Watermelon Fruits (Citrullus lanatus [Thunb]) Transported from the Farm Gates in the Hinterlands to the Urban Markets in the Tamale Metropolis in the Northern Region of Ghana

The perishable nature of fruits and vegetables are a major concern to post harvest scientist. Postharvest handling practices particularly, mode of transportation is contributing to loss of essential chemical qualities of watermelon fruits. This study sought to identify the means of transport responsible for chemical damage in watermelons and also to assess watermelon varieties affected by these modes of transport in the Tamale Metropolis in Ghana. It revealed that watermelon conveyed by Kia Mini Truck (0.80 t) mode of transportation experienced the highest chemical damages (13.82 %) while watermelon conveyed by Mini Pick-up Truck recorded the least chemical damage (13.3%). It also showed that Sugar baby variety encountered the highest chemical damages (13.82%) while Crimson sweet variety recorded the lowest value (13.2 %) Keywords : Chemical qualities, Total tartritable acidity, Total soluble solids, and moisture DOI: 10.7176/JBAH/13-4-05 Publication date: March 31 st 2023

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.

Primary mapping of quantitative trait loci regulating multivariate horticultural phenotypes of watermelon (Citrullus lanatus L.).

Watermelon fruits exhibit a remarkable diversity of important horticultural phenotypes. In this study, we initiated a primary quantitative trait loci (QTL) mapping to identify the candidate regions controlling the ovary, fruit, and seed phenotypes. Whole genome sequencing (WGS) was carried out for two differentiated watermelon lines, and 350 Mb (96%) and 354 Mb (97%) of re-sequenced reads covered the reference de novo genome assembly, individually. A total of 45.53% non-synonymous single nucleotide polymorphism (nsSNPs) and 54.47% synonymous SNPs (sSNPs) were spotted, which produced 210 sets of novel SNP-based cleaved amplified polymorphism sequence (CAPS) markers by depicting 46.25% co-dominant polymorphism among parent lines and offspring. A biparental F2:3 mapping population comprised of 100 families was used for trait phenotyping and CAPS genotyping, respectively. The constructed genetic map spanned a total of 2,398.40 centimorgans (cM) in length and averaged 11.42 cM, with 95.99% genome collinearity. A total of 33 QTLs were identified at different genetic positions across the eight chromosomes of watermelon (Chr-01, Chr-02, Chr-04, Chr-05, Chr-06, Chr-07, Chr-10, and Chr-11); among them, eight QTLs of the ovary, sixteen QTLs of the fruit, and nine QTLs of the seed related phenotypes were classified with 5.32-25.99% phenotypic variance explained (PVE). However, twenty-four QTLs were identified as major-effect and nine QTLs were mapped as minor-effect QTLs across the flanking regions of CAPS markers. Some QTLs were exhibited as tightly localized across the nearby genetic regions and explained the pleiotropic effects of multigenic nature. The flanking QTL markers also depicted significant allele specific contributions and accountable genes were predicted for respective traits. Gene Ontology (GO) functional enrichment was categorized in molecular function (MF), cellular components (CC), and biological process (BP); however, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were classified into three main classes of metabolism, genetic information processing, and brite hierarchies. The principal component analysis (PCA) of multivariate phenotypes widely demonstrated the major variability, consistent with the identified QTL regions. In short, we assumed that our identified QTL regions provide valuable genetic insights regarding the watermelon phenotypes and fine genetic mapping could be used to confirm them.

Effect of drip irrigation regimes and mineral fertilizer rates on watermelon yield in mulched fields

Crop growth in arid and semiarid regions usually depends on irrigation, but inappropriate irrigation practice can result in water stress. Water needs of watermelon are the highest during the period of strong formation of vegetative and generative organs. Thus, 85-90% moisture is required from seeds for seed germination. Before the formation of fruit, soil moisture should be maintained at 70% of the total field moisture capacity of the soil, and at the time of fruit ripening at 60%. In this article, the results of experiments based on the development of optimal irrigation regime and fertilization rate for the cultivation of watermelon plants in mulched fields by drip irrigation method, differentiated soil moisture (60...70...60%, 65...75...65%, 70...80...70%, 75...85...75% SAM (SAM - Soil available moisture)), and fertilization rates (without fertilizer, N100P80K40, N120P100K50 and N140P120K60 kg/ha) have been written. Also, the effect of fertilization rates (N100P80K40, N120P100K50 and N140P120K60 kg/ha) on the quality indicators of watermelon fruit, the amount of dry matter, sugar, nitrates and “C” in the fruit has been noted.

Phenolic Glycosides Citrulluside H and Citrulluside T Isolated From Young Watermelon (Citrullus lanatus) Fruit Have Beneficial Effects Against Cutibacterium acnes-Induced Skin Inflammation

Acne vulgaris, typically caused by Cutibacterium acnes ( C. acnes) involves chronic inflammation of the sebaceous follicles and is the most common skin disease, afflicting 85% of adolescents. We previously isolated 2 novel phenolic glycosides, 2-caffeoyl-3-hydroxy-3-methylbutyric 4′-β-D-glucopyranosyloxy-3′-hydroxybenzyl ester (citrulluside H [CH]) and 2-caffeoyl-3-hydroxy-3-methylbutyric 4′-β-d-glucopyranosyloxybenzyl ester (citrulluside T [CT]), from young fruits of watermelon ( Citrullus lanatus). Both compounds suppressed UVB-induced photoaging in human fibroblasts by scavenging intracellular reactive oxygen species (ROS) and thus might be useful as natural skin care ingredients. In this study, we examined the inhibitory effects of these phenolic glycosides on C. acnes growth and C.acnes-induced inflammation. Neither phenolic glycoside inhibited the growth of C. acnes. However, they both significantly suppressed toll-like receptor (TLR) 1/2 or TLR2/6/nuclear factor κB (NF-κB) signaling in heat-killed C. acnes (hk- C. acnes) -stimulated RAW264.7 cells. Additionally, both phenolic glycosides decreased the expression of M1 macrophage biomarkers (cluster of differentiation [ CD] 80, CD86, and inducible NO synthase [ iNOS]), suggesting that they attenuate M1 macrophage activation. These results indicated that both CH and CT are potential therapeutic substances against C. acnes-induced skin inflammation.

"THE HEALTH BENEFITS OF WATERMELON "

"Watermelon (Citrulus lantus) is an important horticultural crop which belongs to the Curcubitaceae family. The nutraceutical potential of watermelon has been illustrated by several researchers, which makes it a better choice of functional food. Watermelon has been used to treat various ailments, such as cardio-vascular diseases, aging related ailments, obesity, diabetes, ulcers, and various types of cancers. The medicinal properties of watermelon are attributed by the presence of important phytochemicals with pharmaceutical values such as lycopene, citrulline, and other polyphenolic compounds. Watermelon acts as vital source of l-citrulline, a neutral-alpha amino acid which is the precursor of l-arginine, an essential amino acid necessary for protein synthesis. Watermelon is a natural product that contains high level of antioxidants and may prevent oxidative damage in tissues due to free radical generation following an exposure to ionizing radiation. The present study aimed to investigate the radioprotective effects of watermelon. Watermelon is a member of the Cucurbitaceae family native to tropical areas of Africa near Kalahari Desert. Botanists refer it as a «pepo» which is a fruit having a thick rind and fleshy center. It is largely consumed as refreshing summer fruit, much appreciated by the consumers because of its refreshing capability, attractive color, delicate taste, and high water content to quench the summer thirst. According to Oberoi, D. and Sogi S., watermelon fruits yield 55.3 % juice, 31.5 % rind, and 10.4 % pomace. Carotenoids such as lycopene and β-carotene are responsible for the red and orange colors of the watermelon, respectively The sweetness of watermelon is mainly due to a combination of sucrose, glucose, and fructose. Sucrose and glucose account for 20–40 % and fructose for 30–50 % of total sugars in a ripe watermelon. Keywords: watermelon, nutrients, antioxidants, diseases, and consumption. "

Nutrient composition, antioxidant activity and phytonutrient of yogurt incorporated with watermelon fruit pulp and its extract

Yogurt is an ancient food that has been a part of the human diet for thousands of years and has been promoted as a healthy diet. Yogurt is milk that has been fermented and is made by adding two specific bacterial cultures to warm milk, namely Lactobacillus bulgaricus and Streptococcus thermophiles. Yogurt is considered as a cure for diarrhoea, stomach ailments, and irritating skin condition, as well as fungal and yeast infections, and used in some bronchial conditions. High levels of live bacterial cultures in Yogurt contribute to its nutritional and therapeutic properties. The use of different fruits and additives in fruit Yogurt production has improved its nutritional and sensory properties. Citrullus lanatus (Watermelon) is a tropical fruit that contains a variety of nutrients, including fibre, vitamins-A, vitamin B1 and B6, potassium, iodine, magnesium, zinc, and antioxidants which are essential for human health. The addition of watermelon in any commercial product enhances the taste, flavour, and nutrient quality. The objective of the study are: To develop Yogurt incorporated with watermelon fruit pulp and its extract; To perform sensory analysis of Yogurt incorporated with watermelon fruit pulp and its extract; To analyse the nutrient composition, phytonutrient composition and antioxidant activity of the Yogurt incorporated with watermelon fruit pulp and its extract; To calculate cost of the developed Yogurt incorporated watermelon fruit pulp and its extract. The developed watermelon fruit pulp and it extract incorporated yogurt were subjected to sensory evaluation for the overall acceptability with the help of a 5-point hedonic scale with 10 semi- trained members. Which was very well accepted. The nutritional analysis was carried out for protein, fat, iron, calcium, and vitamin C content and was found to be high in watermelon pulp and extract incorporated Yogurt. Thus, watermelon fruit pulp and extract incorporated Yogurt has the potential to be used as a dietary supplement to prevent and control the onset of the degenerative disease among the population.

An exploration into the relationship between mineral elements (nitrogen and phosphorus) and nutritional quality in soil-watermelon (Citrullus lanatus) system

To fundamentally explore the correlation between crop nutritional quality and mineral elements, specific tests and accurate analysis were carried out on all organs and root soil of watermelon (Citrullus lanatus). The results showed that the distribution patterns of nitrogen and phosphorus at watermelon maturity were similar, and the average nitrogen and phosphorus contents were in the orders of leaf and seed > stem, peel, root > pulp > root soil, and peel > seed > root, stem, leaf > root soil > pulp, respectively. From the perspective of element geochemistry, biophile and lithophile elements had the strongest correlation with nitrogen and phosphorus, and watermelon did not antagonize soil nitrogen and phosphorus uptake. The prediction model of nitrogen translocation factor in watermelon organs to total acid was established by partial least squares with R2 = 0.81. Significantly, when the isometric log-ratio of nitrogen to phosphorus in watermelon leaves was 1.97 to 2.19, the watermelon pulp showed better quality with total acid > 0.5%, total sugar > 5% and soluble solids > 10%. Therefore, the characterization of nitrogen and phosphorus in watermelon leaves can serve as a non-destructive analysis to predict watermelon fruit quality.

Physicochemical and Sensory Characteristics of Mixed Fruit Juices Prepared from Blend of Pineapple, Pawpaw and Watermelon Fruits Juices

This study investigated the production of mixed fruit juices from pawpaw, watermelon and pineapple fruits, pawpaw and watermelon fruits. Fresh ripe fruits (pineapple, watermelon and pawpaw and watermelon) were washed, manually peeled, deseeded, sliced, squeezed and sieved to obtain pineapple, watermelon and pawpaw juice pawpaw and watermelon juice. The prepared juices were pasteurized at 85°C for 15 s,sec., packaged in air-tight plastic cans. The pineapple, watermelon and pawpaw juice and watermelon juice were blended in ratios of 100:0:0;0:100:0; 0:100:0; 20:20:60:20; 33.33:33.33:33.33; 60:20:20 and 40:30:30%. The juice samples were evaluated for physicochemical and sensory characteristics using standard procedures. The sensory results showed colour rating of (6.33 - 7.22), flavour (6.11 – 7.78), taste (6.44 – 7.78), and general acceptability of(6.89 – 8.00). Sample 100% PIN was rated the best (8.00) in general acceptability. However, all the juice samples were generally accepted. The physicochemical results showed the following range of values for titrabletitra table acidity (0.60 - 1.21%), total soluble solids (8.10 - 15.55%), total sugar (7.22 - 9.51%), pH (4.05 - 5.30) and vitamin C (4.80-17.00 mg/100g). Generally, the juice samples were within the regulatory specifications, and acceptable. The study showed that fruit juice with good physicochemical and sensory qualities could be formulated using pineapple, watermelon and using pineapple, pawpaw and watermelon blend. The formulated fruit juices could find domestic and industrial applications.

Dietary patterns associated with the risk of pancreatic cancer: Case-control study findings.

Diet is an important modifiable lifestyle factor, but epidemiological studies evaluating the association between dietary patterns and pancreatic cancer (PC) have reported inconsistent findings. This study aimed to evaluate the impact of several dietary choices on the risk of PC among newly diagnosed Jordanian patients. A case-control study was conducted at major teaching and general hospitals, including a Jordanian oncology center. The study included 101 patients with incident pancreatic cancer and 314 controls. Data was collected using interview-based questionnaires. Dietary intake was estimated using a validated Arabic and reproducible food-frequency questionnaire. Dietary patterns were derived using Principal Component Analysis. Multinomial logistic regression was used to estimate the association between dietary patterns and PC. Four dietary patterns were identified. The "Traditional" dietary pattern, which presented a diet rich in fresh fruits, vegetables, milk, yogurt, and lentils, was associated with a significant decrease in the odds of PC (OR = 0.42, 95% CI = 0.21-0.84) for the third quartile compared to first one. The "High-fruit" dietary pattern, which was loaded with strawberry, melon, watermelon, and other fruits, significantly reduced the odds of PC (OR = 0.38, 95% CI = 0.19-0.75) for the second quartile compared to the first one. The "Soup" dietary pattern was mainly composed of vermicelli soup, vegetable soup, lentil soup, and mushroom soup, which decreased the odds of PC (OR = 0.18, 95% CI = 0.07-0.38). There was no relation between PC and the "Western" dietary pattern, loaded with beer, wine, roasted lamb, meat, chicken sandwich, beefsteak, and fried fish. The "Traditional," "High-fruit," and "Soup" dietary patterns were associated with reduced risk of PC among Jordanians.

Dose-response of plasticulture summer squash and triploid watermelon to fomesafen applied pre-transplanting

AbstractDose-response trials to determine the tolerance of summer squash and watermelon to fomesafen applied (over the top of black polyethylene mulch and respective row middles) pre-transplanting were performed between 2020 and 2021 at three Indiana locations: the Meigs Horticulture Research Farm (MEIGS), the Pinney Purdue Agricultural Center (PPAC), and the Southwest Purdue Agricultural Center (SWPAC). Summer squash trials were performed at the MEIGS and PPAC locations, and watermelon trials were performed at the MEIGS and SWPAC locations. The experiments for both summer squash and watermelon had a split-plot arrangement in which the main plot was herbicide rate, and the subplot was cultivar. Summer squash injury included necrotic leaf margin, chlorosis, brown and white spots, and stunting. Fomesafen rates from 262 to 1,048 g ai ha−1 in 2020 at both locations, and from 280 to 1,120 g ai ha−1 in 2021 at MEIGS did not affect summer squash yield. However, in 2021 at PPAC, fomesafen applied at rates from 280 to 1,120 g ha−1 delayed summer squash harvest and decreased marketable yield from 95% to 61% compared with the nontreated control. Watermelon injury included bronzing and stunting. Fomesafen rates from 210 to 840 g ai ha−1 did not affect marketable watermelon yield or fruit number. Crop safety was attributed to rain, which washed off most of the herbicide from the polyethylene mulch before plants were transplanted or little to no rain after transplant. Injury was observed only when there was no rain before transplant followed by excessive rain shortly after transplant. Overall, the 1× rate used for each trial was safe for use 1 d before transplanting summer squash and 6 to 7 d before transplanting watermelon.

Aux/IAA gene Cla004102, is involved in synergistic regulation of various endogenous hormones, regulating flesh firmness in watermelon

Fruit flesh firmness is the key trait of watermelon (Citrullus lanatus) that affects fruit texture, commerciality, and shelf life. However, the knowledge about the underlying molecular mechanisms responsible for variations in fruit flesh firmness is still limited. We constructed a near-isogenic line HWF with high fruit flesh firmness by crossing a wild watermelon PI 271769 as the donor parent and an inbred line 203Z as the recurrent parent. An F2 sub-segregation population was developed by crossing 203Z and HWF for bulked segregant analysis (BSA-seq). The results revealed a candidate region of 6.1Mb (Chr6: 11557845–17658672) containing the genes related to watermelon flesh firmness. RNA Sequencing (RNA-Seq) analysis of the candidate region led to the identification of a candidate gene, Cla004102 (Aux/IAA), an auxin-responsive protein. The expression of Aux/IAA decreased with fruit developmental stages and a reduction in fruit flesh firmness was observed. Moreover, correlation analysis showed a high positive correlation of Aux/IAA with Cla004120, an ethylene-responsive factor1 (ERF1). The RT-qPCR analysis revealed a higher expression of Aux/IAA and ERF1 consistent with flesh firmness. Higher contents of abscisic acid (ABA) were observed in soft fleshed fruits than hard fleshed fruits. Further, applying exogenous ethylene to watermelon fruit reduced flesh firmness, and ABA content was increased much faster in ethylene-treated fruits than in the control. Interestingly, Aux/IAA expression was also decreased with the reduction in flesh firmness and inclined ABA contents. These findings add considerably to the existing knowledge about watermelon fruit flesh firmness. A more in-depth study would better understand watermelon's genetic mechanisms underlying flesh firmness.

Post-harvest assessment of infectious fruit rot on selected fruits in Lafia, Nasarawa State Nigeria

The post-harvest health and microbial safety of plant products and foods continue to be a global concern to farmers, consumers, regulatory agencies and food industries. A study was carried out to evaluate the pathogenicity of fungi associated with post-harvest rot of oranges, watermelons and bananas in Lafia, Nasarawa State, Nigeria. Healthy fruits inoculated with fungal spores obtained from rotted fruit tissues were incubated at ambient temperature conditions and observed daily for the appearance and development of tissue rot. Oranges and Watermelons had the highest number of fungal isolates (3) compared to banana (2). Fungi belonging to the genus Curvularia were the most isolated (37.50%), followed by both Aspergillus and Colletotrichum (25.00% respectively) and lastly Alternaria (12.50%). The highest tissue rot diameter of sweet orange (2.40 cm) was induced by Alternaria sp. followed by Curvularia geniculate (1.40 cm) and lastly Colletotrichum sp. (1.28 cm). The highest rot of banana fruit tissues was produced by A. niger (3.90 cm), followed by Curvularia geniculate (3.40 cm). Aspergillus sp. produced the highest tissue rot diameter on watermelon fruits (1.93 cm), followed by Colletotrichum sp. (1.30 cm) and lastly Curvularia geniculate (1.20 cm). Differences in the susceptibilities of different fruits to rot by fungal pathogens were significant (p ≤ 0.05). There is need for improved handling of fruits after harvest to prevent losses due to bacterial and fungal rots in the study area.

Development and Evaluation of a Watermelon-Harvesting Robot Prototype: Vision System and End-Effector

Over the past decade, there have been increasing attempts to integrate robotic harvesting technology into agricultural scenarios to reduce growing labour costs and increase crop yields. In this paper, we demonstrate a prototype harvesting robot for picking watermelons in greenhouses. For robotic harvesting, we design a dedicated end-effector for grasping fruits and shearing pedicels, which mainly consists of a flexible gripper and a cutting device. The improved YOLOv5s–CBAM is employed to locate the watermelon fruits with 89.8% accuracy on the test dataset, while the K-means method is used to further refine the segmentation of the watermelon point cloud in the region of interest. Then, the ellipsoid is fitted with the segmented fruit point cloud to obtain the lowest point of the ellipsoid as the grasping point. A series of tests conducted in a laboratory simulation scenario proved that the overall harvesting success rate was 93.3% with a positioning error of 8.7 mm when the watermelon was unobstructed. The overall harvesting success rate was 85.0% with a positioning error of 14.6 mm when the watermelon was partially obscured by leaves.