Effect of Algae on Melon(Cucumis melo subsp.agrestis var.conomon)Growth and Development under Drought-Stress Conditions

Due to climate change,it is necessary to develop plant varieties that are resilient to climate conditions and resistant to abiotic and biotic stresses.The use of microalgae,which are microorganisms that contain carbohydrates,proteins,lipids,and vitamins,against drought tolerance is a new approach.The aim of the current study was to determine the drought-related mechanisms in the conomon melon genotype and develop drought-tolerant melon cultivars.Morphological,physiological,pomological,and molecular analyses were carried out on the algae-treated genotypes.It has been determined that commercial algae application provides the best results in leaf temperature,leaf relative water contents(LRWC),plant height,fruit length,fruit diameter,and yield,while Cag Cag(a special river in the region)stream algae application gives better results in main stem diameter.It was determined that the number of nodes in the control(without algae)plots was higher than in the other two treatments.Yield and LRWC and plant height values of genotype 7 were the best values among other genotypes.The leaf temperature measurement was lower on genotype 9 than on the other genotypes.While the highest fruit length value was measured in genotype 1,genotype 8 was superior in the main stem diameter,fruit diameter,and the number of nodes among the remaining plant materials.In terms of yield,it was determined that the interaction between genotype 2 and the commercial algae resulted in the best outcomes.In addition,the results of the genetic evaluation revealed that the materials used were not genetically distant from each other and more detailed genetic evaluations are needed.The molecular kinship analysis revealed that the genotypes used in the study were divided into three distinct groups,with individuals within each group exhibiting a high degree of relatedness to one another.As a result of the study,it was found that the application of microalgae had significant effects on improving the drought tolerance of Cucumis melo subsp.agrestis var.conomon genotypes.

Breeding melon(Cucumis melo)with resistance to powdery mildew and downy mildew

Melon(Cucumis melo L.)production is often restricted by a plethora of pests and diseases,including powdery mildew and downy mildew caused respectively by the fungal species Podosphaera xanthii/Golovinomyces orontii and oomycete species Pseudoperonospora cubensis.Many efforts have been directed on identification of resistant sources by screening(wild)melon germplasm.In the current review,we summarized such efforts from various publications of the last 50 plus years.Resistance to powdery mildew has been identified in 239 melon accessions and downy mildew resistance in 452 accessions of both C.melo and the wild relative species C.figarei.Among the resistance sources,C.melo var.cantalupensis accessions PMR 45,PMR 5,PMR 6,and WMR 29 as well as C.melo var.momordica accessions PI 124111,PI 124112,and PI 414723 have been considered as the most valuable germplasm because multiple resistance genes have been identified from these accessions and are widely used in melon resistance breeding.Further genetic mapping in a number of resistant sources has enabled identification of 25 dominant genes,two recessive genes and seven QTLs conferring powdery mildew resistance,as well as eight dominant genes and 11 QTLs for downy mildew resistances.Based on the reported sequences of associated markers,we anchored physically(many of)these genes and QTLs to chromosomes of the melon cv.DHL92 genome.In addition to presenting a comprehensive overview on powdery mildew and downy mildew resistance in(wild)melon germplasm,we suggest strategies aiming at breeding melon with durable and broad-spectrum resistance to pathogens and pests.

Antihyperglycemic and antihyperlipidemic activities of wild musk melon (Cucumis melo var. agrestis) in streptozotocin-nicotinamide induced diabetic rats

Objective:Wild musk melon(Cucumis melo var.agrestis,CMA)is one of the edible plants form Tamil Nadu.Traditionally,this plant was used as diabetic diet(leaves of CMA with Momordica charantia leaves),but there is no scientific report on antidiabetic action of this plant material.Hence,the current research work was designed to evaluate the antihyperglycemic and antihyperlipidemic effect of hydroalcoholic extract of CMA leaves(HALEC)in streptozotocin(STZ)-nicotinamide(NIC)-induced diabetic rats.Methods:Diabetes was induced by administration of STZ(60 mg/kg,i.p.)after 15 min of NIC(120 mg/kg i.p.)administration.The diabetic rats were treated with HALEC(300 and 600 mg/kg,p.o.,respectively)for 21 d.Results:After the management with HALEC,blood glucose,HbA1c levels,total cholesterol,LDL cholesterol,triglycerides levels,glycogen phosphorylase and glucose-6-phosphatase levels were significantly diminished in diabetic rats.However,haemoglobin level,HDL cholesterol,liver glycogen,total protein,hexokinase,glucose-6-phosphate dehydrogenase levels were significantly increased in HALEC treated diabetic rats.The histopathological studies of the pancreas in HALEC-treated diabetic rats showed almost normal appearance.L6 cell line study revealed the increased glucose uptake activity of HALEC.High performance thin layer chromatography(HPTLC)analysis confirms the presence of active principles such as rutin,gallic acid and quercetin in HALEC.Conclusion:The results indicated that HALEC possess significant antihyperglycemic and antihyperlipidemic activity in STZ-NIC-induced typeⅡdiabetic rats with protective effect.This research work will be useful for the isolation of active principles and development of herbal formulation in phytopharmaceuticals.

Effects of Meteorological Conditions on Yield and Quality of Facility Hami Melon

With different varieties of facility Hami melon(Cucumis melo var. sacchairinus) as test materials, the effects of meteorological conditions on the yield and quality of different varieties of facility Hami melon were analyzed. The results showed that among the yield and quality traits of melon, the variation degree of average single melon weight was the highest, and the coefficient of variation was 33.05%. The variation degree of leaf area index was the lowest, and the coefficient of variation was 11.00%. Through the correlation analysis of meteorological factors with the yield and quality of facility Hami melon, it was found that the quality traits of facility Hami melon were significantly positively correlated with maximum temperature and sunshine duration, and significantly negatively correlated with precipitation. The yield traits were positively correlated with maximum temperature, sunshine duration and precipitation.

The Study of Allelochemicals of the Melon Fly (Myiopardalis pardalina Bigot.)

This study describes the isolation, identification of allelochemicals of the melon fly (Myiopardalis pardalina Bigot.), using the GC-MS method. A food attractant has been identified and a method for the synthesis of its synthetic analogue has been developed. Also, a route for the synthesis of para pheromone, raspberry ketone, has been proposed.

QTL-seq identifies major quantitative trait loci of stigma color in melon

Stigma color plays an important role in pollination.In nature,melon(Cucumis melo L.)stigmas are either yellow or green;however,a review of the literature found no report on how stigma color affects pollination and fruit development in melon.Here,we used an F_(2)melon population derived from a cross between‘MR-1’(P_(1),with green stigmas)and‘M1–32’(P_(2),with yellow stigmas),and performed genetic analysis and mapping.The results of bulked segregant analysis allowed the identification of genetic loci controlling stigma color on chromosomes 6 and 8.An F2 population consisting of 150 individuals was used for initial mapping.A genetic map of 304.17 cM was constructed using 37 cleaved amplified polymorphism sequence(CAPS)markers.We identified one major quantitative trait locus(QTL)and one minor QTL for stigma color.The major QTL GS8.1 was further mapped to a 4.13 cM interval between CAPS markers 8C-10 and 8C-16,which explained 27.04%of the phenotypic variation.In addition,GS6.1 was mapped between E-49 and 6A-7,explaining 18.6%of the phenotypic variation.This study provides a theoretical basis for the fine mapping and cloning of melon genes controlling stigma color.

Identification of Differentially Expressed Genes During Ethylene Climacteric of Melon Fruit by Suppression Subtractive Hybridization

Melon （Cucumis melo L.） is an important horticultural crop worldwide. Ethylene regulates the ripening process and affects the ripening rate. To screen genes that are differentially expressed at the burst of ethylene climacteric in melon fruit, we performed suppression subtractive hybridization （SSH） to generate forward and reverse libraries, for which we sequenced 439 and 445 clones, respectively. Our BLAST analysis showed that the genes from the 2 libraries were involved in metabolism, signal transduction, cell structure, transcription, translation, and defense. Six genes were analyzed by qRT-PCR during the differential developmental stage of melon fruit. Our results provide new insight into the understanding of climacteric ripening of melon fruit.

Modeling Study of Fruit Morphological Formation in Melon

Modeling of fruit morphological formation in melon is important for realizing virtual and digital plant growth.The objective of this study was to characterize the changes in patterns of fruit growth characters during plant development.In cultivar experiments,a high-resolution wireless vision sensor network has been developed to realize non-contact automatic uninterrupted measurement of the fruit shape micro-change （fruit size,color,and net）.Results showed that the fruit swelling process （vertical and horizontal diameters） exhibited a slow-rapid-slow pattern,which could be well described with a logistic curve against growing degree days （GDD）;fruit color changes based on the RGB values could be represented by quadratic relationship to cumulative GDD;the fruit net changes over growth progress could be partitioned into three phases according to the time interval.The first phase was from 1 to 30 days after pollination （DAP）,in which the vertical stripe appeared at fruit middle part and the horizontal stripe at fruit petiole and hilum part as well;the second phase was from 30 to 40 DAP,the horizontal stripe occurred at fruit middle part and the net was formed;the third phase was the process started from 40 DAP,the netted breadth and thickness were gradually increased.The model was validated with the independent data from the experiment,and the mean RMSE （root mean square error） of fruit were 0.36 and 0.28 cm for vertical and horizontal diameters,11.9 for fruit color,and 0.45 cm for stripe length and diameter at varied GDD,respectively.This work is beneficial to a reliable foundation for study the relationship between morphological formation and physiological change of the melon fruit internally and then realize the intelligent precision management to improve the yield and quality of greenhouse melon production.

Wild melon: a novel non-edible feedstock for bioenergy

In the present research work, a non-edible oil source Cucumis melo var. agrestis （wild melon） was systematically identified and studied for biodiesel production and its characterization. The extracted oil was 29.1% of total dry seed weight. The free fatty acid value of the oil was found to be 0.64%, and the single-step alkaline transesterification method was used for conversion of fatty acids into their respective methyl esters. The maximum conversion efficiency of fatty acids was obtained at 0.4 wt% NaOH （used as catalyst）, 30% （methanol to oil, v/v） methanol amount, 60 ℃ reaction temperature, 600-rpm agitation rate and 60-min reaction time. Under these optimal conditions, the conversion efficiency of fatty acid was 92%. However, in the case of KOH as catalyst, the highest conversion （85%） of fatty acids was obtained at 40% methanol to oil ratio, 1.28 wt% KOH, 60 ℃ reaction temperature, 600-rpm agitation rate and 45 min of reaction time. Qualitatively, biodiesel was characterized through Fourier transform infrared spectroscopy （FFIR） and gas chromatography and mass spectroscopy （GC-MS）. FTIR results demonstrated a strong peak at 1742 cm-1, showing carbonyl groups （C=O） of methyl esters. However, GC-MS results showed the presence of twelve methyl esters comprised of lauric acid, myristic acid, palmitic acid, non-decanoic acid, hexadecanoic acid, octadecadienoic acid and octadecynoic acid. The fuel properties were found to fall within the range recommended by the international biodiesel standard, i.e., American Society of Testing Materials （ASTM）： flash point of 91℃, density of 0.873 kg/L, viscosity of 5.35 cSt, pour point of - 13 ℃, cloud point of -10 ℃, total acid number of 0.242 mg KOH/g and sulfur content of 0.0043 wt%. The present work concluded the potential of wild melon seed oil as excellent non-edible source of bioenergy.

Quality of Melon 'UFERSA-05 var.ACIDULUS and Pele de Sapo“Mabel”Minimally Processed,Kept in Different Packages

This study aimed at evaluating the quality of melon Pele de Sapo “Mabel” and Yellow melon “UFERSA-05” minimally processed preserved in different packages. The fruits were harvested at Mossoró-RN and transported to Serra Talhada-PE. In the first study, melon fruit Piel de Sapo “Mabel” was selected, washed, weighed, cooled, peeled, cut into cube shape, sanitized in chlorine solution, drained, packaged in rigid polypropylene tray, sealed with polypropylene film or polypropylene rigid cap and kept for 8 days at 8℃. In the second study, fruits of yellow melon “UFERSA-05” and Pele de Sapo “Mabel” were minimally processed and kept in rigid polypropylene tray, sealed with polypropylene film and stored for 8 days at 8℃. There was no significant interaction between packaging (sealed with film and polypropylene cover) and period of conservation, for pH, total titratable acidity (TTA), total soluble solids (TSS) and Loss of fresh mass (LFM) for Melon “Mabel”. While there was significant interaction between types of melon (“UFERSA-05” and “Mabel”) and storage period (0, 2, 4, 6, and 8 days) for pH, TTA and TSS. In sensory evaluation were noticeable changes in appearance, flavor, aroma and flesh firmness, characterized by translucency, alcoholic aroma and softening in “Mabel” melon kept in tray with lid. Melon “UFERSA-05” showed lower pH, total soluble solids, total soluble sugars, PME activity, lack of translucency high flesh firmness compared to “Mabel” melon during storage. The high levels of sugars in melon “Mabel” may be related to the incidence of translucency, which was not observed in “UFERSA-05” melon, with a strong potential to minimal processing.

哈密瓜镰刀果腐菌的鉴定、生物学特性和室内防治药剂的筛选

【目的】鉴定引起哈密瓜(Cucumis melo L.)果蒂处的果肉腐烂病原菌种类,以及对不同宿主的致病性检测,探讨光照、温度、pH值、碳源、氮源及不同药剂处理对该菌生长的影响,并筛选出哈密瓜镰刀果腐病的有效防治方法。【方法】采用组织分离法,从发病的哈密瓜果实中分离病原菌,结合形态学与核糖体内转录间隔区(rDNA-ITS)、转录延伸因子EF-1α和组蛋白Histone3序列的分子鉴定确定病原菌种类。测定不同的培养温度、pH、碳源、氮源、光照及需氧条件对其生长的影响。用NaHCO;、硼酸、施保功、苯甲·嘧菌酯和纳他霉素处理,观察各种药剂的抑菌效果。再用罗丹明123、健那绿B、线粒体红色荧光探针(Mito Tracker;Red CMXRos)及溴化丙啶(PI)染色,了解不同药剂处理对病原菌细胞膜透性及线粒体功能的影响,用安全性较高的纳他霉素对哈密瓜进行室内防效实验,了解纳他霉素对病原菌的防治效果。【结果】病原菌为哈密瓜果腐变红镰刀菌(Fusarium incarnatum,编号ZJHM-01),孢子形态呈镰刀状,长度为25.4~35.5μm,宽度为3.3~5.4μm;病原菌生物学特性测定结果表明,宿主具广谱性,光照能促进生长,最适生长温度为30℃,最适p H为7~9,最适碳源为淀粉、山梨醇和葡萄糖,最适氮源为蛋白胨和牛肉膏。1.0%NaHCO;、1.2%硼酸、0.025%施保功、0.016%苯甲·嘧菌酯和40 mg·L^(-1)纳他霉素均能完全抑制病原菌生长。罗丹明123染色结果发现,1.0%NaHCO;、1.2%硼酸和30 mg·L^(-1)纳他霉素处理使菌丝的细胞膜透性增加;健那绿B和Mito Tracker;Red CMXRos染色发现,药剂处理降低了菌丝的线粒体活性;PI染色结果表明,病原菌细胞膜完整性遭到破坏,线粒体活性和线粒体膜电位受损。纳他霉素室内防效表明,纳他霉素处理的果实发生病害时间明显延后且症状减轻,说明纳他霉素具有较好的防病效果。【结论】果实采收期,生产上用施保功和苯甲·嘧菌酯防治哈密瓜镰刀菌果腐病。果实采收后,用1.0%NaHCO;、1.2%硼酸和40 mg·L^(-1)纳他霉素浸泡果实处理以降低哈密瓜镰刀菌果腐病的发生率。从食品安全性考虑,纳他霉素应该作为哈密瓜采后镰刀菌果腐病防治的首选药剂。研究结果为哈密瓜镰刀菌果腐病防治提供了新的方法。

甜瓜果肉颜色变化与类胡萝卜素关系研究

试验以4种不同果肉色泽的甜瓜(Cucumis melo L.)品种:白肉型、绿肉型、浅桔红肉型、橘红肉型为材料,研究甜瓜果实发育过程中果肉色泽和类胡萝卜素含量的变化,分析果肉色泽a、b与类胡萝卜素含量间的拟合关系。结果表明,浅桔红肉、橘红肉、绿肉型甜瓜发育过程中L均呈下降趋势,果肉颜色变深;浅桔红肉、橘红肉型甜瓜a、b均持续升高,果肉向红色、黄色变化;绿肉型甜瓜a、b均呈下降趋势,向黄绿色转变;白肉型甜瓜L、a变化不显著,但b由20.9显著下降至6.3。橘红肉型、浅桔红肉型甜瓜类胡萝卜素含量与a线性拟合系数分别为0.773 2、0.910 4,与b线性拟合系数分别为0.882 6、0.822 9,均呈正向极显著相关;白肉型甜瓜类胡萝卜素含量与b线性拟合度达0.463 7,呈显著正相关。类胡萝卜素含量可以通过色差仪快速测定a、b来近似表示。

豆饼与尿素配施对薄皮甜瓜果实酯类香味物质及关键酶的影响

以薄皮甜瓜(Cucumis melo var. makuwa Makino)果实为试材,研究了豆饼、尿素及豆饼与尿素配施对薄皮甜瓜果实酯类香气物质及关键酶的影响。结果表明,尿素处理促进了C6醇和C9醇、C6醛和C9醛物质合成,抑制了乙酸脂类和非乙酸酯类物质的合成;豆饼与尿素配施明显促进了果实中酯类物质的种类和含量的增加,尤其是提高了成熟果实中乙酸乙酯、乙酸己酯、2-甲基丁酸乙酯、异丁酸乙酯4种特征性酯类物质的含量,而豆饼处理主要是促进了非特征性酯类物质的种类和含量的增加。此外,不同处理甜瓜果实酯类物质的合成与关键酶活性变化相关,尤其是ADH和AAT活性。

宜昌早春大棚厚皮甜瓜品种的筛选

为选择适宜宜昌地区早春大棚种植的厚皮甜瓜(Cucumis melo)品种,选择了7个厚皮甜瓜品种与种植面积较广的长江蜜魁进行品种比较试验,通过对生物学性状、果实品质及产量等指标的调查分析,从中选出综合性状表现良好的品种。结果表明,参试品种众天8号产量较高,生育期适中,口感爽脆,抗病性较强,有较强的推广价值;七彩脆蜜因其果肉独特,口感爽脆,有一定的推广价值。

气象条件对设施哈密瓜产量和品质的影响分析

以不同品种设施哈密瓜(Cucumis melo var.sacchairinus)为试验材料,分析了气象条件对设施哈密瓜产量和品质的影响。结果表明,设施哈密瓜的产量和品质性状中,平均单瓜质量的变异程度最大,变异系数为33.05%,叶面积指数的变异程度最小,变异系数为11.00%。通过气象因子与设施哈密瓜产量和品质的相关性分析发现,设施哈密瓜的品质性状与最高温度和日照时长呈显著正相关,与降水量呈显著负相关;产量性状与最高温度、日照时长和降水量呈显著正相关。

哈密瓜生长气象条件评价指标及主要气象灾害影响分析

以新疆哈密市中熟哈密瓜(Cucumis melo var.saccharinus)为研究对象,应用1981—2020年气象数据资料、1999—2020年哈密瓜发育期资料、1961—2020年历史灾情资料,分析了哈密瓜生长的气象条件及主要气象灾害。结果表明,影响哈密瓜生长的主要气象因子有播种期、出苗期、伸蔓期的平均气温、平均最高气温和(或)平均最低气温,坐果期的气温日较差、平均相对湿度、降水量,成熟期的日照时数等。哈密瓜苗期适宜温度为18~25℃,日最高气温>35℃或日最低气温≤13℃对苗期生长有不利影响;果实膨大期的适宜温度为25~30℃;坐果期至成熟期的高温和持续降水会对哈密瓜的产量和品质造成影响。哈密瓜生长期间的主要气象灾害是苗期大风和霜冻。1999—2020年哈密市春季霜冻和大风灾害均以轻度为主。

Ultrastructure of compatible and incompatible interactions in phloem sieve elements during the stylet penetration by cotton aphids in melon

Resistance of the melon line TGR-1551 to the aphid Aphis gossypii is based on preventing aphids from ingesting phloem sap. In electrical penetration graphs （EPGs）, this resistance has been characterized with A. gossypii showing unusually long phloem salivation periods （waveform El） mostly followed by pathway activities （waveform C） or if followed by phloem ingestion （waveform E2）, ingestion was not sustained for more than 10 min. Stylectomy with aphids on susceptible and resistant plants was performed during EPG recording while the stylet tips were phloem inserted. This was followed by dissection of the penetrated leaf section, plant tissue fixation, resin embedding, and ultrathin sectioning for transmission electron microscopic observation in order to study the resistance mechanism in the TGR. The most obvious aspect appeared to be the coagulation of phloem proteins inside the stylet canals and the punctured sieve elements. Stylets of 5 aphids per genotype were amputated during sieve element （SE） salivation （El） and SE ingestion （E2）. Cross-sections of stylet bundles in susceptible melon plants showed that the contents of the stylet canals were totally clear and also, no coagulated phloem proteins occurred in their punctured sieve elements. In contrast, electron-dense coagulations were found in both locations in the resistant plants. Due to calcium binding, aphid saliva has been hypothesized to play an essential role in preventing/suppressing such coagulations that cause occlusion of sieves plate and in the food canal of the aphid＇s stylets. Doubts about this role of E 1 salivation are discussed on the basis of our results.

Sieve element occlusion provides resistance against Aphis gossypii in TGR-1551 melons

Feeding behavior and plant response to feeding were studied for the aphid Aphis gossypii Glover on susceptible and resistant melons(cv.Iroquois and TGR-1551,respectively).Average phloem phase bout duration on TGR-1551 was<7% of the duration on Iroquois.Sixty-seven percent of aphids on TGR-1551 never produced a phloem phase that attained ingestion(EPG waveform E2)in contrast to only 7% of aphids on Iroquois.Average bout duration of waveform E2(scored as zero if phloem phase did not attain E2)on TGR-1551 was<3% of the duration on Iroquois.Conversely,average bout duration of EPG waveform El(sieve element salivation)was 2.8 times greater on TGR-1551 than on Iroquois.In a second experiment,liquid nitrogen was used to rapidly cryofix leaves and aphids within a few minutes after the aphids penetrated a sieve element.Phloem near the penetration site was then examined by confocal laser scanning microscopy.Ninety-six percent of penetrated sieve elements were occluded by protein in TGR-1551 in contrast to only 28% in Iroquois.Usually in TGR-1551,occlusion was also observed in nearby nonpenetrated sieve elements.Next,a calcium channel blocker,trivalent lanthanum,was used to prevent phloem occlusion in TGR-1551,and A.gossypii feeding behavior and the plants phloem response were compared between lanthanum-treated and control TGR-1551.Lanthanum treatment eliminated the sieve element protein occlusion response and the aphids readily ingested phloem sap from treated plants.This study provides strong evidence that phloem occlusion is a mechanism for resistance against A.gossypii in TGR-1551.

甜瓜栽培品种的遗传多样性研究

为了通过分子水平了解甜瓜品种的遗传多样性,利用36个SSR标记对浙江省种植的甜瓜品种进行遗传多样性研究。结果表明,33个具有多态性SSR标记共产生97个等位基因,每个标记平均产生2.9个等位基因。多态性信息含量(PIC)变化范围为0.029~0.746,平均值为0.412。聚类分析表明,33份材料可明显分成两大类,分别对应于厚皮甜瓜和薄皮甜瓜类型。调查了不同甜瓜品种的果实性状和品质性状,发现有些性状如果形、果重、香气、质地等在厚皮甜瓜和薄皮甜瓜间存在差异。研究结果表明,厚皮甜瓜品种遗传多样性较丰富,但需要利用更多的分子标记才能有效地鉴别不同薄皮甜瓜品种。本研究为高效合理利用品种资源提供了有用信息,为甜瓜育种提供了物质基础。

利用SSR标记快速检测甜瓜‘天美55’种子纯度与真实性

为了快速、准确检测薄皮甜瓜‘天美55’的种子纯度与真实性,本研究根据甜瓜基因组信息,设计了64对SSR引物,以‘天美55’及其亲本为试验材料进行筛选,发现其中6对在双亲材料中具有多态性差异,其后又从中选出4对特异性较强且条带清晰稳定的引物cm-27、cm-33、cm-73、cm-92。利用该4对引物对6份‘天美55’F_(1)代杂交种样品进行纯度检测,与田间检测结果相比较,两种方法结果偏差≤1.5%,说明4对引物稳定可靠,可用于‘天美55’甜瓜杂交种的纯度检测;利用该4对引物对3份同类型品种进行检测,结果其中2对引物可以完全区分,2对引物可以部分区分,说明4对引物具有较高的特异性,可以用于‘天美55’甜瓜杂交种的真实性鉴定。