High-quality and high-phytonutrient watermelon fruits have strong market opportunities besides their health related benefits. Hence, investigating quality and nutritional related traits of watermelon genetic resources could provide important baseline data in breeding for increased lycopene content thereby increasing the marketability of watermelon. To this end, we have examined some fruit morphological traits and lycopene content of 105 genetic resources. Seeds, originally obtained from 22+ countries, were obtained from the National Agrobiodiversity Center, Jeonju, South Korea, grown in an experimental field and harvested at a fully mature stage. The size of pistil scar (SPS), the width of stripes (WS), weight of fruit (WF), length of fruit (LF), width of fruit (WIF), the thickness of pericarp (TP), soluble solids content (SSC), fruit shape in longitudinal section, ground color of skin, the intensity of the green color of skin, fruit shape at the apical part, grooving distribution, conspicuousness of stripes, and main color of the flesh were recorded on the field and inside laboratory and the lycopene was measured using spectrophotometric and HPLC methods. Watermelon fruits have shown a diverse morphological characters. Red and pink fleshed fruits dominated in the entire collections. Fruits with higher thickness of rind were found to exhibit less soluble solid content (SSC). Korean origin fruits were characterized by intermediate SSC while the United States of America (USA), Russia (RUS), Tajikistan (TJK), Turkmenistan (TKM), Taiwan (TWN), and Uruguay (URY) originated fruits had the highest SSC. The lycopene content varied between 41.37 and 182.82 ㎍/g, 2.81 and 163.72 ㎍/g, and 3.54 and 255.47 ㎍/g using HPLC, UV-Vis spectrophotometer, and microplate reader spectrophotometer, respectively. Red- and pink-fleshed fruits had the highest levels of lycopene content compared to the yellow- and orange-fleshed. Lycopene content had a significant positive correlation with SSC, however, no correlations were detected between lycopene and other quantitative fruit morphological characters. Our study demonstrated high diversity exists in fruit morphological traits and lycopene content of the germplasm collections which provide beneficial baseline data for a future breeding program and utilization of watermelon germplasm collections in gene banks for the maintenance and improvement of the current levels of production, marketability, and health-related benefit of watermelon fruits.

This study was carried out to determine the effect of Kluyvera sp. CL-2 (KACC 91283P) on the growth of watermelon (Citrullus vulgaris L.). The study consisted of three treatments, no treatment (NT), twice application of Kluyvera sp. CL-2 before transplanting (KC1), and five times application around transplanting (KC2). We determined the chemical properties of soil before and after the treatments, and compared the growth characteristics of watermelon among treatments. The treatment of Kluyvera sp. CL-2 at 1.0×106 cfu mL-1 significantly increased available P2O5. The organic matter showed to increase for all treatments, while soil pH, exchangeable Ca and Mg tended to decrease for all treatments. The leaf width was increased by 11.6% for KC1 and 26.2% for KC2 compared to NT. But there were no significant differences in yield, leaf length, fruit weight, fruit length, fruit width, and pericarp thickness among treatments. The contents of free sugars such as fructose and glucose were increased by microbial treatments but sucrose was not different from NT. The content of glucose in watermelon was increased by 13.8% in KC1 and 12.8% in KC2 compared to NT. The content of fructose increased by 14.6% in KC1 and by 39.8% in KC2 compared to NT. The results from the study imply that Kluyvera sp. CL-2 can be used to increase sugar content in watermelon.

The paper aims to estimate efficiency of watermelon by using a bootstrapping approach to generating efficiency estimates through Monte Carlo simulation resampling process. We use the input-output data for watermelon 107 farmers. The main results are as follows. The estimates of efficiency depends on the methodology. The estimates of general DEA is greater than the bootstrapping method. The technical efficiency and pure technical efficiency measure of watermelon is 0.72, 0.82 respectively. However the bias-corrected estimates are less than those of DEA. We know that the DEA estimator is an upward biased estimator. According to these results, the DEA bootstrapping model used here provides bias-corrected and confidence intervals for the point estimates, it is more preferable.

본 연구는 소과종 수박의 병해충 발생 양상을 조사하고 이중 가장 문제가 되는 병 들 중 의 하나인 흰가루병을 방제하기 위한 유기농업자재를 선발하기 위하여 수행되었다. 2015년 충북 음성에서 소과종 수박에 발생하는 병해충 조사 결과 덩굴마름병, 흰가루병, 목화진딧 물, 점박이응애, 총채벌레류, 파밤나방, 담배거세미나방 등 일반수박에 발생하여 피해를 주 는 대부분의 병해충이 발생하는 것을 확인할 수 있었다. 이중 흰가루병은 6월 중순에 품종 별로 27~99.3%의 발생률을 나타냈으며 점박이응애는 6월 중순에 품종별로 엽당 마릿수가 79.9~111마리로 높은 발생을 보였다. 또한, 총채벌레류는 6월 중순과 상순에 황색과 청색 평판점착트랩 각각에 트랩당 407마리와 774마리로 높은 유살수를 나타냈다. 포장에서 마 요네즈와 올레산 그리고 현재 시판 중인 유기농업자재 3종에 대한 흰가루병 방제 효과를 조사하였다. 조사 결과 sodium bicarbonate 80%가 함유된 자재, 마요네즈 그리고 대황추출 물 1%가 함유된 자재가 60% 이상까지 효과적으로 병 발생을 감소시켰으며, 이중 sodium bicarbonate 80%가 함유된 자재가 83%로 가장 높은 방제가를 나타냈다. 본 연구를 통해 소 과종에 발생하는 병해충에 대한 정보와 sodium bicarbonate 80% 함유 자재가 흰가루병 방제 에 효과적이라는 것을 알 수 있었다.

In nine commercial watermelon cultivars, the effects of osmotic seed priming were evaluated for seed viability and seedling growth at different germination temperatures and field conditions. Generally, primed seeds showed improved germination rate and reduced time for emergence at different germination temperatures, as compared to untreated seeds. In particular, priming effect on seed germination was significantly high at 15℃, which is an environment normally resulting in poor germination. Depending on the watermelon cultivar, germination rate under low temperature (15℃) was improved by up to 15~66% in primed seeds, as compared to untreated seeds. However, priming effect on germination was gradually reduced as the temperature reached to its optimum level for seed germination. Seed priming tended to improve the viability, fresh weight, and dry weight of watermelon seedlings, but its effect on seedling stage was not large, as compared to untreated seeds. Primed watermelon seeds showed improved emergence rate and facilitated germination in the field, but their seedling growth after 30 days from germination was not significantly affected. Our results indicated that seed priming can greatly improve the seed germination at poor temperature conditions in the watermelon.

The aim of the present study was to determine the effects of soil microbial agent with red ginseng marc on growth of watermelon during 5 months. The three treatments were distributed in a completely randomized design with four replicates per plot. After 1 week in planting dates, the growth of watermelon (full length, stem thichness, leaf length and lead width) showed no significant difference in all treatments. During elongation stage (20 days), soil microbial agent with red ginseng marc was increased by 5% in leaf thickness (May 23) and 7~14% in leaf length (May 16 and 23) when compared to other treatments. For changes in fruit bearing thickness, there were no differences among treatments. Characteristics of watermelon in harvest season have an effect on harvest and length, stalk length, naval length, weight, sugar content and yield, except for harvest and width. In particular, yields increased with treatments with two soil microbial agent (7~12%), indicating that soil microbial agent with red ginseng marc showed higher yield than the other treatments. In conclusion, red ginseng marc-treated soil microbial agents have a positive effect on the harvest season of watermelon and can provide useful information for the selection of the functional microbial properties and the registration of microbial fertilizer.

This study was conducted to investigate days after anthesis (DAA) and fruit after-ripening period (FAP) for seed-harvesting of high quality watermelon seeds. Fruit weight and number of seed per fruit increased according to DAA, while those did not significant about FAP. Ratio of cotyledon at whole seed was higher about 2 to 4% compared to seed coat irrespective of DAA and FAP. Germinability of watermelon was not a significant effect by DAA, however, it had differences by FAP. Percent of germination (PB) was below 50%, when 30 days maturated fruits after anthesis was omitted ripening, while PB was increased to 92% by ripening. In addition, seeds at DAA 40 and FAP 20 were higher general seedling vigors (hypocotyl length, diameter etc.) in BP test. Results indicated that considering seed productivity, it had maximized seed viability at DAA 40 and FAP 20.

This study was conducted to investigate the effects of fruit set internode on the germination of watermelon seeds. Generally fruits setted in higher than 20 internode were high percent of germination, fruit setted in low internode(5-10) is low. The higher fruit-set internode, fruit weight was significantly increased, but 1,000 seed weight was decreased the more fruit set internode. However number of seed was about 300 seeds irrespective of fruit-set internode. Investigating viability of seed by BP test, general percent germination was recorded highest at 5 flower cluster above 20 internode of fruit-set internode. In contrast, condition of fruit setted on 3, 4, 6 flower cluster were high percent of germination, regarded as unnormal germination not to be as normal seedling by 2~3%. Seed harvested at 5 flower-cluster had high viability on hypocotyl height and diameter of seedling through early growth test, but were not significant. Therefore 5 flower-cluster was optimum fruit-set internode to obtain high-quality seed.

To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.

Recently, many breeders have preferred to use molecular markers for introgression backcross programs enabling foreground and background selection to cope with rapid cultivar changing of seed markets. In accumulation of target traits with marker-assisted selection, larger numbers of markers should give better resolution. For the analysis of quantitative traits, a high-density genetic map with a large number of markers is required for discovering more accurately linked markers with traits. Watermelon is a recalcitrant plant to generate a high-density genetic map with conventional molecular markers including simple sequence repeats (SSRs), since watermelon has narrow genetic diversity background and severe segregation distortions of those SSR markers. Thus, we have developed efficient and valid way to assemble genetic map and markers by next-generation sequencing coupled with genotyping by sequencing in F2 generation. After crosses between Citurullus lanatus ssp. citroides (PI254744 and PI189225) and C. lanatus ssp. lanatus (TS34, Korean cultigen), 163 of F2 progeny were sequenced through Illumina's Hi-Seq GAII platform. From sequence information of those variant call files, the SNPs were indexed and filtered by sequencing depth with genotype converter (SNP Genotyper), and optimized by heuristic physical bin mapping to construct more reliable genetic linkage map. Reliable SNP loci were determined and compared to sequences of physical reference map. Using the genetic map, we determined QTLs in F2:3 population and found major loci corresponding to seed size and powdery mildew race1 resistance in watermelon.

본 연구는 수박 과실썩음병의 원인균인 A. avenae subsp. citrulli에 대해 항균활성을 갖는 친환경 유기농자재를 개발할 목적으로 오배자(S. chinensis)를 대상으로 수행되었다. 오배자를 MeOH로 추출하여 용매분획을 하였고, 용매분획 중에서 가장 강한 활성을 나타낸 hexane fraction을 column chromatography로 분리하여 활성이 강한 분획들을 GC-MS로 분석하였다. GC chromatogram 상의 주요 peak에 해당하는 mass spectrum과 Wiley library를 비교하여 profiling한 결과, 지방산인 myristic acid, palmitic acid와 3-n-pentadecylphenol이 주요 물질로 검출되었다. 이들 검출 화합물의 항균활성을 검정하기 위하여 표준품을 사용하여 bioassay한 결과, myristic acid와 3-n-pentadecylphenol 화합물이 강한 활성을 보였다. 따라서 오배자로부터 분리한 myristic acid와 3-n-pentadecylphenol 화합물이 항균 활성물질인 것을 구명하였다.

본 연구는 수박유통에 있어 수확시 꼭지를 T 형태로 자르는 관행적 방법과 꼭지를 제거할 경우 저장성에 미치는영향을 구명하고자 수행되었다. 실험에 사용한 수박의 평균 무게는 7.8 kg이었고 각각 7℃와 실온에 저장하면서 여러요인들을 조사하였다. 무게는 저장일수가 길어짐에 따라 감소하였는데 꼭지처리한 수박을 7℃에서 30일 저장한 경우 그 무게가 0.6~0.7% 감소한 반면 실온에서는 1.9~2% 감소하였으며 동일 온도조건하에서는 꼭지유무에 따른 유의차는 없었다. 경도는 초기 755 g에서 저장일수가 경과함에 따라 점차 감소하였으며 실온에서 저장하였을 경우542~549 g으로 더 큰 감소폭을 보였으나 같은 온도조건하 에서는 꼭지유무에 따른 차이는 없었다. 저장기간 동안 pH,총산과 내부 수분은 모든 처리에서 큰 변화를 보이지 않았으며, 가용성고형분은 실온에 저장한 것은 초기 평균 11.3°Brix에서 30일 후에는 9.3°Brix로, 수박 내부의 적색도는 초기 36.7에서 저장후기에는 처리별로 31.7~33.6으로 감소하였으며, 유리당총량은 저장전 8,133 mg/100 g에서 초기에는 증가하다가 저장기간이 길어질수록 감소하였는데 이들 변화 역시 동일저장조건에서의 꼭지유무에 따른 유의적 차이는 나타나지 않았다. 따라서 수박을 수확할 때 꼭지를 T 형태로 남긴 것과 제거한 것이 저장성에 미치는 영향은 없으므로 생산, 유통 등을 고려하여 꼭지를 제거하는 것이 바람직하다고 판단된다.

본 연구는 수박 과실썩음병의 원인균인 Acidovorax avenae subsp. citrulli 균에 대해서 항균활성을 갖는 친환경 유기농자재를 개발할 목적으로 약용식물 133종을 대상으로 진행되었다. 이들 133종 약용식물의 MeOH 추출물에 대한 bioassay를 통해 항균 활성을 검정한 결과 청피(Citrus unshiu Markovich) 추출물에서 강한 항균활성을 보였다. 청피(Citrus unshiu Markovich)로부터 항균활성물질을 구명하고자 용매분획을 하였고, 용매분획 중에서 hexane fraction이 가장 강한 활성을 나타내었다. Hexane fraction을 GC-MS로 분석하여 chromatogram상의 각각의 peak에 해당하는 mass spectrum과 Wiley library를 비교하여 profiling 한 결과, essential oil인 d-limonene, γ-terpinene, β-linalool, terpineol과 지방산인 palmitic acid, 9,12-octadecadienoic acid, linolenic acid 그리고 steroid 화합물인 stigmasterol이 검출되었다. 이들 검출화합물 중에서 항균 활성물질로 추정되는 d-limonene, γ-terpinene, β-linalool, terpineol의 항균 활성을 검정하기 위해 표준품을 사용하여 bioassay한 결과 두 화합물 dlimonene, γ-terpinene에서 높은 항균활성을 보였다. 따라서 본 연구를 통해 청피로부터 분리한 d-limonene과 γ-terpinene 화합물이 항균 활성물질인 것을 구명하였다. 항균력이 강한 청피 추출물 또는 d-limonene과 γ-terpinene을 주성분으로 하는 추출물을 수박 과실썩음병에 대한 친환경 방제용 자제로 개발이 가능할 것으로 판단되었다.

Watermelon (Citrullus vulgaris L.) is a summer fruit typical to help fatigue systemic absorption is getting better. The goal of this study is to screen antioxidant activity to ensure the possibility as a functional material for exocarp of watermelon. Watermelon was extracted with 70% methanol, 70% ethanol, chloroform:methanol (CM, 2:1, v/v). Total phenol contents were 12.01 mg/g, 8.89 mg/g, 3.53 mg/g in the 70% methanol, 70% ethanol, CM, in that order, respectively. Total flavonoid content, DPPH radical scavenging activity, ABTS radical scavenging activity, ferric reducing antioxidant power (FRAP), β-carotene bleaching assay were 70% methanol extract remarkably higher than the other extracts. And these results showed the same trend of total phenol content. From the above results shows that watermelon was effective on the antioxidative activity.

This study was performed to analyze genetic relationship of the four major Cucurbitaceae crop. We used 120 Expressed Sequence Tag(EST)-Simple Sequence Repeat(SSR) primer sets of developed from watermelon and published in International Cucurbit Genomics Initiative (ICuGI) database. Among 120 EST-SSR primer, 51(49.17%) EST-SSR primer set successfully amplified and 49(40.8%) EST-SSR primer set showed polymorphisms among eight cultivars of Cucurbitaceae. In the first instance, amplified PCR products analysis was conducted by the agarose-gel electrophoresis then further analyzed by using Fragment Analyzer. A total 382 PCR band were producted by 49 EST-SSR primers in 24 plant panels, used the analysis of pairwise similarity and dendrogram construction. Assessment of the genetic relationships resulted in similarity index with range of 0.0103 to 0.8452. In dendrogram, 24 plant panels were formed three major groups (A, B, C) and 7 subgroups (A-1, A-2, B-1, B-2, B-3, C-1, C-2). Major group A was comprised of 2 subgroups, subgroup A-1 (6 watermelon cultivars, Citrullus lanatus var. vulgaris Schrad.) and subgroup A-2 (3 wild type watermelon, Citrullus lanatus var. citroides Mats. & Nakai). Major group B was comprised of 3 subgroups, subgroup B-1 (4 melon cultivars, Cucumis melo var. cantalupensis Naudin.), subgroup B-2 (2 oriental melon cultivars, Cucumis melo var. conomon Makino.) and subgroup B-3 (5 cucumber cultivars, Cucumis sativus L.). Major group C was comprised of 2 subgroups, subgroup C-1 [2 squash/ pumpkin cultivars, Cucurbita moschata (Duch. ex Lam.)/Duch. & Poir. and Cucurbita maxima Duch.] and subgroup C-2(2 squash/pumpkin cultivars, Cucurbita pepo L./Cucurbita ficifolia Bouche.)

Many viruses infect cucurbits. One of the well-known symptoms is mosaic disease. Those that cause mosaic are cucumber mosaic virus (CMV), squash mosaic virus (SqMV), watermelon mosaic virus (WMV), zucchini yellow mosaic virus (ZYMV) and cucumber green mottle mosaic virus (CGMMV). WMV resistant GM squash was developed many years ago in the United States and it was on the market, but no further information was available by now pertinent to commercial aspect. Usually these viruses are not easily controlled by frequent applications of chemicals that target the insect as carriers of viruses. Therefore, it is necessary to develop commercial varieties possessing resistance against viral diseases. We have developed GM watermelon rootstocks called gongdae, using a coat protein gene of CGMMV as transgene. Those GM watermelon rootstocks showed highly resistant to CGMMV, and have been crossed to get the several BC and T generation. In order to obtain the virus resistant watermelon, watermelon lines were crossed to the selected GM watermelon rootstock. Here, we present the successful watermelon cultivars that show resistance to CGMMV. The resistance must have obtained by transferring the transgene from the GM watermelon rootstock to watermelon line

수박은 토마토에 비하여 라이코핀 함량이 60% 높으며, 라이코핀 고함유 수박 품종개발에 관심이 집중되고 있다. 그러나 라이코핀 함량 분석을 위한 대량 분석 체계가 마련되지 않아 고함유 유전자원의 선발에 어려움이 있었다. 따라서 본 연구에서는 신속하고 간편한 lycopene 함량 분석기술의 개발과, 개발된 기술(microplate법)을 이용하여 라이코핀 고함유 유전자원을 선발하고자 하였다. 그 결과 UV spectrophotometer를 이용한 방법을 개선하여 Microplate법을 개발하였다. Microplate법은 HPTLC를 이용한 방법과 약 97%로 높은 정의 상관을 나타내어 분석의 정확성이 높은 방법임을 확인하였다. 따라서 Microplate법을 이용하여 수박 유전자원, 계통 및 96점을 대상으로 수박 과실의 라이코핀 함량을 분석한 결과 라이코핀 함량이 생체중 1 g 당 3.2∼98.3 μg･g-1의 넓은 변이를 보였다. 선발 유전자원은 시판 대비품종(스피드플러스; 10.3 μg･g-1 FW)에 비하여 4.4∼9.6배 높은 수준이었다. 선발된 자원들은 라이코핀 고함량 품종개발에 이용 될 수 있을 것으로 판단되었다.

Many viruses infect cucurbits. One of the well-known symptoms is mosaic disease. Those that cause mosaic are cucumber mosaic virus (CMV), squash mosaic virus (SqMV), watermelon mosaic virus (WMV), zucchini yellow mosaic virus (ZYMV) and cucumber green mottle mosaic virus (CGMMV). WMV resistant GM squash was developed many years ago in the United States and it was on the market, but no further information was available by now pertinent to commercial aspect. Usually these viruses are not easily controlled by frequent applications of chemicals that target the insect as carriers of viruses. Therefore, it is necessary to develop commercial varieties possessing resistance against viral diseases. We have developed GM watermelon rootstocks called gongdae, using a coat protein gene of CGMMV as transgene. Those GM watermelon rootstocks showed highly resistant to CGMMV, and have been crossed to get the several BC and T generation. In order to obtain the virus resistant watermelon, watermelon lines were crossed to the selected GM watermelon rootstock. Here, we present the successful watermelon cultivars that show resistance to CGMMV. The resistance must have obtained by transferring the transgene from the GM watermelon rootstock to watermelon line.