Watermelon Varieties Research Articles

Allelic variations of ClACO gene improve nitrogen uptake via ethylene-mediated root architecture in watermelon.

The ClACO gene encoding 1-aminocyclopropane-1-carboxylate oxidase enabled highly efficient 15N uptake in watermelon. Nitrogen is one of the most essential nutrient elements that play a pivotal role in regulating plant growth and development for crop productivity. Elucidating the genetic basis of high nitrogen uptake is the key to improve nitrogen use efficiency for sustainable agricultural productivity. Whereas previous researches on nitrogen absorption process are mainly focused on a few model plants or crops. To date, the causal genes that determine the efficient nitrogen uptake of watermelon have not been mapped and remains largely unknown. Here, we fine-mapped the 1-aminocyclopropane-1-carboxylate oxidase (ClACO) gene associated with nitrogen uptake efficiency in watermelon via bulked segregant analysis (BSA). The variations in the ClACO gene led to the changes of gene expression levels between two watermelon accessions with different nitrogen uptake efficiencies. Intriguingly, in terms of the transcript abundance of ClACO, it was concomitant with significant differences in ethylene evolutions in roots and root architectures between the two accessions and among the different genotypic offsprings of the recombinant BC2F1(ZJU132)-18. These findings suggest that ethylene as a negative regulator altered nitrogen uptake efficiency in watermelon by controlling root development. In conclusion, our current study will provide valuable target gene for precise breeding of 'green' watermelon varieties with high-nitrogen uptake efficiencies.

Use of water-soluble microfertilizers for growing meteor table variety watermelon

Relevance. In connection with the introduction of various types of chelated microfertilizers into production, it is necessary to develop new elements of varietal technology for the cultivation of melons and gourds in order to obtain stable yields in the arid conditions of the Volgograd Trans-Volga region. These studies will be relevant in this period of time.Material and technique. The object of research is watermelon, variety Meteor. We studied the types and methods of using chelate microfertilizers: Helaton Extra, Chelate B, Chelate Fe. Fertilizers were used for soaking seeds before sowing and for foliar treatment of plants during the growing season.Results. During the research period of 2019-2021, new forms of microfertilizers were studied. As a result of the research, new preparations for different methods of processing had a positive effect on the growth and development of table watermelon plants. The evaluation of the results obtained showed a positive effect of new microfertilizers on the germination energy and seed germination. The maximum growth of lashes was recorded when seeds were soaked before sowing: Helaton Extra preparation and foliar feeding of plants during the growing season with microfertilizer boron chelate. The best results of increasing the leaf surface were obtained in variants with the use of Helaton Extra microfertilizer for soaking seeds and treating plants on vegetative organs. Accordingly, the highest yield was obtained when using Helaton Extra fertilizer for seed treatment before sowing and spraying plants during the growing season. The output of marketable products was noted at a fairly high level. The average weight of the fetus in all studied variants ranged from 5.9 kg to 7.8 kg. The length of the growing season in all variants increased slightly. Comparative analysis of growth processes and productivity of watermelon variety Meteor when using new forms of water-soluble fertilizers for seed soaking and foliar treatment of plants showed greater efficiency from their use.

Influence of chelated microfertilizers on growth processes and yield of table watermelon under agricultural conditions of the Volgograd Volga region

Relevance. The Volgograd region is a region of risky farming. In the spring-summer period, the cultivated crop (melons) is often exposed to stress factors: spring frosts, abnormal heat, temperature changes, which negatively affects the growth and development of plants. In this regard, it is necessary to develop new adaptive agrotechnical methods for the cultivation of melons and gourds in order to obtain stable yields of high quality.Material and methodology. The object of research is watermelon, variety Meteor. Water-soluble fertilizers were studied – Helaton Extra and Aquarin vegetable for soaking seeds before sowing and foliar treatment of plants during the growing season.Results. During the research period of 2019-2021, new types of microfertilizers were studied.When using preparations Aquarin vegetable and Helaton Extra for different methods of processing, a positive effect on the growth and development of table watermelon plants, as well as on the increase in the leaf plate, was noted. Helaton Extra for soaking seeds and treating plants had the maximum impact on the growth processes of early table watermelon. As a result of the research, the yield of the studied variety also increased. The average weight of the fetus in all variants increased compared to the control variant by 2.7-5.3%. The length of the growing season in all variants increased from 2 to 4 days, which favorably affected the increase in yield. Comparative analysis of growth processes and productivity of watermelon variety Meteor when using new forms of water-soluble fertilizers for seed soaking and foliar treatment of plants showed greater efficiency from their use.

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.

A meta-analysis on rootstock-induced effects in grafted watermelon (Citrullus lanatus var. lanatus)

Sweet watermelon (Citrullus lanatus var. lanatus) grafting with complementary rootstocks is necessary for new variety design and to enhance product profiles, including fruit yield and quality and tolerance to biotic and abiotic stresses.. Integrated selection of successful watermelon grafts using multiple traits ensures breeding and economic gains. Therefore, the objective of this study was to undertake a meta-analysis on the responses of watermelon when grafted with contrasting rootstocks involving cucurbit species or interspecific hybrids using agronomic, physiological and quality traits, and insect pest and disease reactions for rootstock selection, variety development and deployment. A meta-analysis was conducted involving 65 studies, and data were analysed using various statistical methods. Results indicated significant (p < 0.05) variations among watermelon varieties for economic traits when grafted onto different cucurbit rootstock species. Interspecific hybrid [Cucurbita maxima × C. moschata] and Lagenaria siceraria (Molina) Standl rootstocks induced high and variable effects on fruit yield and related traits of grafted watermelon.. Watermelon/L. siceraria graft combinations showed high phenotypic variation on sugar profiles. Lycopene content of grafted watermelon was highly variable when grafted onto C. lanatus var. citroides and C. maxima × C. moschata rootstocks. Graft combinations involving L. siceraria and C. maxima × C. moschata were significantly (p < 0.05) differentiated for fruit flesh firmness and color. C. lanatus var. citroides rootstock enhanced low and variable infections for root-knot nematodes, whereas C. maxima × C. moschata rootstock induced high and variable resistance to Fusarium and Verticillium wilt in grafted watermelon. Fruit yield and quality traits of grafted watermelon positively and significantly (p <0.05; p <0.001) correlated with root and photosynthetic parameters useful in selection programs. Overall, the meta-analysis revealed the need to integrate root traits (e.g., increased root weight and total root length, higher root surface area and average root diameter), high photosynthetic efficiency, fruit yield and quality in selecting desirable rootstock in the development of market preferred watermelon varieties.

Production Test Of 5 Watermelon Variety Candidates (Citrullus Lanatus (Thunb.) Matsum. &amp; Nakai) F1 Hybrida Result Of Assembly Against 4 Comparing Varieties

Watermelon (Citrullus lanatus) is a widely consumed and cultivated fruit in Indonesia, cherished for its numerous benefits, high economic value, and short plant life. To enhance watermelon quality, plant breeding is employed, aiming to develop superior hybrid varieties. This study, conducted between September and November 2022 on PT. Aditya Sentana Agro's experimental land, evaluated candidate hybrid watermelon varieties (codes 3078, 3079, 3080, 2844, 2845) against comparison varieties (Winda, Mardi, Black Panther, Palguna). Using Randomized Complete Block Design (RCBD) with one genetic factor at 9 levels, repeated 3 times, a total of 27 experimental units were established, each consisting of 10 plants, summing up to 270 plants. Qualitative variables such as fruit skin color, pattern color, flesh color, and shape, along with quantitative variables like fruit weight, length, diameter, dissolved solids, flowering day, skin thickness, and percentage of fruit damage, were observed. The research revealed variations in fruit weight, length, diameter, dissolved solids, and flowering day among the different varieties. Promising candidates for new varieties were identified as codes 2845 and 3078 based on these quantitative traits. This study contributes valuable insights into the potential advancements in watermelon breeding, emphasizing the importance of selecting varieties with desirable characteristics for improved agricultural outcomes.

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.

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

Growth dynamics of the fruit of members of the Cucurbitaceae family

In this article, the results of the research conducted to study the growth dynamics of the fruits of plants belonging to the Cucurbitaceae family, the fruit growth took place along a simple sigmoid curve: at first, the size and weight of the fruit increased exponentially, then this process slowed down, and it was given with an in-depth scientific analysis. It was noted that the ratio of fruit formation and ripening periods was 1:2 in "Uzbeksky 740" and "Margelansky 822" varieties of cucumber, and that the period of fruit formation in "Uzbeksky 452" and "Kuzybay 30" watermelon varieties was slightly longer than its ripening period.

Seasonal and daily blooming rhythm of watermelon (Citrullus lanatus) belonging to Cucurbitaceae family

5-6 days after the watermelon seed germinated and formed a seedling, the first leaf appeared, and then every 3-4 days, leaves appeared in the next (second, fifth) short leaf interval. After the appearance of leaves, growth and development slowed down, and the seedlings became small erect bushes with unformed curls. Watermelon blooming begins 40-50 days after planting the seeds. Male flowers bloomed first, followed by female flowers 10-15 days later. Mass blooming of male flowers occurs in 60-65 days, and female flowers in 75-80 days. Male flowers bloomed 35-40 days after seed germination in the early-ripening “Uzbekskiy 452” variety of watermelon we studied and in the late-ripening “Quzibay 30” variety 45-55 days after seed germination. 6-10 days after the blooming of the male flowers, the fruit-bearing flowers bloomed in the axils of the 5-30 leaves of the main branch (stem). In the variety “Uzbekskiy 452”, the first male and fruit-bearing flowers were located throughout the plant. Blooming of fruit-bearing flowers on the main branches of “Uzbekskiy 452”, variety began on 43-47 days after germination, and on 52-60 days on “Quzibay 30” variety.

Выращивание сельскохозяйственных культур после рыбоводного пруда при освоении залежи

In the Astrakhan region, for long-term saline fallow reclaimed lands in the rice engineering system, flushing is required when they are involved in an active agricultural turnover. In modern conditions, keeping the land simply under "water vapor" is ineffective, therefore, before growing crops, rice checks are used as fish ponds. The purpose of the study was to establish the effect of the duration of the fish pond on the hydrophysical, agrochemical indicators of the soil, weediness and yielding capacity of crops in the rotation system during reclamation of the fallow. A one-year and two-year stay of a check under a fish pond contributed to an increase in the content of humus by 0,08-0,11%, organic matter by 0,44-0,53%, easily hydrolysable nitrogen by 6,1-9,2 mg/kg, mobile phosphorus by 9,3-16,4 mg/kg, mobile potassium by 5,4-8,2 mg/kg, moisture reserves in the soil by 1,9-2,5 times and reduced the weediness of barley crops with alfalfa overseeding by 6,5-10,9 times. Grain yield of spring barley variety AS Lacomb was 3,8-4,2 t/ha, green mass of alfalfa Nadezhda – 9,0-11,0 t/ha. A two-year-old pond as a predecessor for growing watermelon in the crop rotation created more favorable conditions for obtaining high-quality cucurbitaceous products, the average yield and marketability for varieties was higher in the mid-season group - by 3,3 t/ha and 0,7% and in the middle-late group – by 1,3 t/ha and 0,3% compared to a one- year pond as a predecessor. The content of dry matter and the amount of sugars exceeded the standards for all studied varieties of watermelon in two groups of ripeness. The largest amount of dry matter and the amount of sugars were found after a two-year pond for the watermelon variety Belye rosy and they were 12,15% and 10,08% respectively.

A Study On Bio Efficacy Of Cyantraniliprole 10.6% OD Against Major Sucking Pests Of Watermelon

Cyantraniliprole, 10.6% OD, was evaluated in the field against major sucking pests of watermelon at Jaguli Instructional Farm, Bidhan Chandra Krishi Viswavidyalaya (BCKV) during 2020-21. The study took place during the kharif season, and the watermelon variety named ‘Krishna’ was selected and grown with proper agronomic practices. A total of three sprays were done starting from the ETL of the pest population. The spraying was done at ten days intervals with four different doses of Cyantraniliprole, 10.6% OD along with Imidacloprid 17.8% SL @ 100 g a.i./ha, Spinosad 45% SC @ 73 g a.i./ha (standard checks) and an untreated control. All the treatment is arranged in randomized block design with three replications, each consisting of seven treatments. The results revealed that treatments cyantraniliprole 10.6% OD @ 120 g a.i/ha and 90 g a.i/ha were substantially more potent with regard to its efficacy on the basis of three sprays, compared to untreated control.

Genotyping by Sequencing (GBS)-Based QTL Mapping for Bacterial Fruit Blotch (BFB) in Watermelon.

Watermelon (Citrullus lanatus), an economically important and nutritionally rich Cucurbitaceous crop grown worldwide, is severely affected by bacterial fruit blotch (BFB). Development of resistant cultivar is the most eco-friendly, cost-effective, and sustainable way to tackle this disease. This requires wider understanding of the genetics of resistance to BFB. In this study, we identified quantitative trait loci (QTLs) associated with BFB resistance in an F2 mapping population developed from BFB-resistant 'PI 189225' (Citrullus amarus) and -susceptible 'SW 26' (C. lanatus) genotypes based on the polymorphic markers identified by genotyping by sequencing (GSB). A linkage map covering a total genetic distance of 3377.1 cM was constructed. Two QTLs for BFB resistance, namely, ClBFB10.1 and ClBFB10.2, both located on chromosome 10 explaining 18.84 and 15.41% of the phenotypic variations, respectively, were identified. Two SNP-based high-resolution melting (HRM) markers WmBFB10.1 and WmBFB10.2 having high positive correlation with resistance vs. susceptible alleles were developed. The efficacy of the markers was validated in another F2 population derived from SW34 × PI 189225. The highest phenotypic variation was found in the locus ClBFB10.2, which also contains three putative candidate genes for resistance to BFB. These findings will accelerate the development of BFB-resistant watermelon varieties via molecular breeding.

Near-infrared hyperspectral imaging for online measurement of the viability detection of naturally aged watermelon seeds.

The viability status of seeds before sowing is important to farmers as it allows them to make yield predictions. Monitoring the seed quality in a rapid and nondestructive manner may create a perfect solution, especially for industrial sorting applications. However, current offline laboratory-based strategies employed for the monitoring of seed viability are time-consuming and thus cannot satisfy industrial needs where there is a substantial number of seeds to be analyzed. In this study, we describe a prototype online near-infrared (NIR) hyperspectral imaging system that can be used for the rapid detection of seed viability. A wavelength range of 900-1700 nm was employed to obtain spectral images of three different varieties of naturally aged watermelon seed samples. The partial least square discriminant analysis (PLS-DA) model was employed for real-time viability prediction for seed samples moving through a conveyor unit at a speed of 49 mm/sec. A suction unit was further incorporated to develop the online system and it was programmatically controlled to separate the detected viable seeds from nonviable ones. For an external validation sample set showed classification accuracy levels of 91.8%, 80.7%, and 77.8% in relation to viability for the three varieties of watermelon seed with healthy seedling growth. The regression coefficients of the classification model distinguished some chemical differences in viable and nonviable seed which was verified by the chromatographic analysis after the detection of the proposed online system. The results demonstrated that the developed online system with the viability prediction model has the potential to be used in the seed industry for the quality monitoring of seeds.

Pollination Effectiveness of the Hoverfly Eristalinus aeneus (Scopoli, 1763) in Diploid and Triploid Associated Watermelon Crop.

Watermelon (Citrullus lanatus) is an important crop worldwide. Pollination of this crop is carried out by insects, with honey bees (Apis spp.) and bumble bees (Bombus spp.) as the most used in greenhouse production. Nevertheless, due to the extreme conditions in closed enclosures, these hymenopterans suffer management and behavior problems leading to insufficient pollination. The effectiveness of three release densities (15, 30, and 45 individuals/m2) of Eristalinus aeneus was compared in diploid- and triploid-associated watermelon varieties under protected cultivation. Floral visits, pollen-pistil interaction after pollen transport, yield, and fruit quality were evaluated. The number of floral visits increased with release density in both pistillate and staminate flowers. No significant differences were observed, however, among release densities or between flower types in the duration of the visits. Floral preferences were not found in the behavior of E. aeneus in watermelon. High and medium release densities increased pollen deposition onto the stigma, and consequently the yield of the triploid variety compared to low release density, by 23.8 to 41.8% in 2020 and by 36.3 to 46.7% in 2021. The results of this trial demonstrate the potential of E. aeneus as a managed pollinator in protected cultivation of triploid watermelon.

RESPON PERTUMBUHAN DAN HASIL TANAMAN SEMANGKA (Citrullus vulgaris Schard) AKIBAT PEMBERIAN POC LIMBAH BUAH BUAHAN DI TANAH GAMBUT

This study aims to determine the best interaction between watermelon varieties and the application of liquid organic fertilizer from fruit waste, the best dose, and the suitable varieties for cultivation on peat soils. The design used was a 4 x 2 factorial RCBD (Randomized Completely Block Design) with 3 replications. The factors studied arethe variety (V) consists of two levels, namely: V1: Amara F1, V2: Garnis F1, and liquid organic fertilizer (P), consists of four levels, namely: P0: 0/liter of water, P1: 30 mL +970 mL of water/plot, P2: 60 mL+940 mL of water/plot, P3: 90 mL+910 mL of water/plot. The results showed that there was no interaction between varieties and liquid organic fertilizers. The varieties had a significant effect on plant length, the number of leaves, flowering time, and fruit length. The suitable variety was Garnis F1. The liquid organic fertilizers had a significant effect on fruit weight per plot, and fruit diameter with the best dose of 30 mL+970 mL of water/plot on the Garnis F1 variety. The highest fruit sweetness rate (7.72 Brix) at the best dose 90 mL+910 mL of water/plot on the Garnis F1 variety

Influence of Poultry Manure Application Rates on Red and Yellow Varieties of Watermelon (Citrullus lanatus) in the Marginal Mineral Soil of Bukit Kor (Marang)

Increased crop yields and higher soil quality can be achieved by using the appropriate amount of fertiliser at the right time. A study on optimal poultry fertiliser rates for watermelon development on nutrient deficient soil, contributes to the current knowledge base. Thus, this paper intends to ascertain the effect of different application rates of poultry fertilizer on growth and yield properties of two cultivars of watermelon (Citrullus lanatus) on soil with marginal nutrients. Accordingly, an experiment was conducted at Universiti Malaysia Terengganu's research farm at Bukit Kor (Marang) to compare the effects of various application rates (T1: 0T/Ha, T2: 10T/Ha, T3: 20T/Ha, T4: 30T/Ha) of poultry manure on the performance of two watermelon varieties (V1:yellow variety (golden delight) and V2:red variety (new dragon)). Several growth and yield parameters were determined, of which the treatments on the red variety at 20THa^-1 and 30THa^-1 produced the significant higher results for vine length (189.38 & 189.43cm), number of leaves (61 & 63), number of lateral branches (2.5 & 2.33), leaf area index (0.12 & 0.13), chlorophyll content SPAD (36.32 & 37.03), fruit weight (10.23 & 9.84THa^-1) and number of flowers (8.33 & 11.7). The present research, therefore, contributes to a growing body of evidence suggesting that the red variety of watermelon treated with 20THa^-1 or 30THa^-1 presented the best results.

Impact of Fertilizer Sources and Water Supplies on the Growth and Yield of Watermelon Varieties in Oyo State, Nigeria

Impact of Fertilizer Sources and Water Supplies on the Growth and Yield of Watermelon Varieties in Oyo State, Nigeria

Study of varieties and promising varieties of table watermelon in the conditions of the Volgograd Volga region

Relevance. Selection and analysis of the source material for crossing varieties with an individual ability to transmit economically valuable traits to offspring is an important breeding task. Breeders conducted research aimed at obtaining highly productive varieties and hybrids of table watermelon of various ripeness groups, resistant to adverse environmental conditions and having high taste qualities in comparison with standards. When studying the varieties and varietals of table watermelon, samples were selected according to the following characteristics: the growing season, yield, bright color of the pulp, excellent taste, dry matter content.Materials and methods. Scientific research was carried out in 2019-2020 in the breeding nursery and breeding nursery in the fields of the Bykovskaya melon breeding experimental station located in the Bykovsky district of the Volgograd region. 2 varieties of Malachite, Timosha and 3 cultivars 697, 728, 750 having an advantage in valuable economic characteristics over the best zoned varieties in the middle–ripening group – Sinchevsky, and in the late-ripening group – Kholodok were studied.Results. Studies have shown that in the middle–ripening group, the new Timosha variety is the most productive (27.3 t/ha), and the variety also stood out with a high dry matter content (13.4 - 14.8%). In the late-maturing group, a variety of 750 (27.5 t/ha) was distinguished by yield. Indicators of dry matter, the percentage of dry matter higher in the cultivar 728 ranged from 13.8 to 14.8%, The tests proved the relevance of further study in the breeding nursery of selected cultivars isolated by a complex of economically valuable traits to create new promising varieties of watermelon. Work in this direction will contribute to an increase in the volume and quality of manufactured products, contribute to the further development of the melon industry.

FIRST RECORD for WATERMELON NECROSIS DISEASE on WATERMELON CROP in IRAQ

This research was carried out during a severe unknown disorder epidemic wave was spread out on watermelon crop over all Iraqi provinces that causing significant economic losses to the farmers of this crop. The research included conducting a field survey covering about 183 hectares of watermelon fields during the spring agricultural season in four Iraqi provinces; Baghdad, Kirkuk, Erbil, and Penguin/Sulaymaniyah. According to this survey, the disease occurrence percentage ranged from 70-100% in Baghdad, Kirkuk, and Erbil, while it was around 10-20% only in the Penguin/Sulaymaniyah area. It is also noted that plants growing under the shade of trees or long intercropped crops like sunflower, were escaped from the infection. Despite many watermelon varieties cultivated by farmers during the survey year, no resistant or tolerant varieties were observed, and minor differences in their susceptibility were noticed. The disease is diagnosed as Watermelon rind necrosis (WRN) depending on intensive field and laboratory investigations conducted for this purpose. Bacteria were isolated from necrosis spots in the watermelon rind, but the same was isolated also from the healthy tissues in the watermelon rind with less intensity. A high correlation was found between disease occurrence and the amount of difference between night and day temperature during the first month before the fruit ripening. This research finding is considered the first record of watermelon rind necrosis (WRN) disease on the watermelon crop in Iraq