Melon Types Research Articles

Sensory and analytical characteristics of a novel hybrid muskmelon fruit intended for the fresh-cut industry

A novel hybrid muskmelon has been bred specifically for use by the fresh-cut industry in winter. Quality characteristics of fresh-cut pieces from the hybrid were compared to those of its inbred parental lines and to those of a commercial netted muskmelon (cantaloupe) and a non-netted muskmelon (honeydew) fruit available in winter. Pieces from hybrid and female line fruit had higher soluble solids content (SSC) and firmness, and lower aromatic volatile concentrations compared to those from the male line fruit. Pieces from hybrid fruit also had higher SSC (>3%) and were firmer (>5 N) than commercial fruit available during the winter, and had twice the aromatic volatile concentration of commercial honeydew and a more intense orange hue than commercial muskmelon. Consumers rated the flavor, texture, sweetness and overall eating quality of the hybrid higher than its inbred parents and winter-available honeydew and as well as or better than winter-available muskmelon. Hybrid fruit stored 5 weeks at 1 °C under modified atmospheric conditions, then fresh-cut and stored 14 d in air at 5 °C maintained good quality (firmness = 51 N, SSC > 12%, β-carotene and ascorbic acid concentrations = 18 and 182 mg kg −1, respectively), and showed no signs of tissue translucency or surface pitting despite microbial populations >11 log 10 kg −1. The results indicate that the novel hybrid muskmelon is a promising new melon type for fresh-cut processing and marketing, at least during the winter season.

Chinese melon (Cucumis melo L.) diversity analyses provide strategies for germplasm curation, genetic improvement, and evidentiary support of domestication patterns

The genetic diversity of melon market types (Cucumis melo L., 2n = 2x = 24) in China, an important secondary center of diversity, has not been examined. Therefore, reference accessions from India and Africa, Crete/Greece, Japan, Europe, U.S.A., Spain, and 68 Chinese cultigens (fresh-market non-netted thin-skinned; non-netted thick-skinned; netted thick-skinned; and non-netted thin-skinned, and vegetable) were evaluated by using 17 10-mer RAPD primers (32 mapped loci), days to flower, sex expression, lateral-branch number, and fruit number and weight per plant. While Chinese thin-skinned melons differed from vegetable melon types only in sex expression, the U.S. Western Shipping market type reference accession “Top Mark” and Chinese thick-skinned melons were similar for all of the morphological traits examined. The average similarity (Jaccard Coefficient) between any two pairs of accessions examined as estimated by RAPD variation was 0.47 ± 0.14. Within-group genetic similarities ranged between 0.94 (thin-skinned type) and 0.08 (non-netted thick-skinned type). The average/standard deviation, maximum, and minimum similarity between any two Chinese reference accessions was 0.41 ± 0.13, 0.75, and 0.12, respectively. Cluster analysis partitioned accessions into two main branches consisting of Group Cantalupensis and Inodorus reference accessions (clade 1) and Chinese accessions (clade 2). A second cluster analysis partitioned China, India, and Africa accessions into one major group, and accessions from Japan, Europe, and U.S.A. into another. Results indicate that Chinese accessions are a rich source of genetic diversity for plant improvement, and that molecular assessments support previously described theoretical melon domestication patterns constructed from historical and archeological evidence.

Development of molecular markers linked to the Fom-1 locus for resistance to Fusarium race 2 in melon

Fusarium wilt, caused by Fusarium oxysporum f. sp. melonis (F.o.m), is a worldwide soil-borne disease of melon (Cucumis melo L.). The most effective control measure available is the use of resistant varieties. Resistance to races 0 and 2 of this fungal pathogen is conditioned by the dominant gene Fom-1. An F2 population derived from the ‘Charentais-Fom1’ × ‘TRG-1551’ cross was used in combination with bulked segregant analysis utilizing the random amplified polymorphic DNA (RAPD) markers, in order to develop molecular markers linked to the locus Fom-1. Four hundred decamer primers were screened to identify three RAPD markers (B17649, V01578, and V061092) linked to Fom-1 locus. Fragments amplified by primers B17649 and V01578 were linked in coupling phase to Fom1, at 3.5 and 4 cM respectively, whereas V061092 marker was linked in repulsion to the same dominant resistant allele at 15.1 cM from the Fom-1 locus. These RAPDs were cloned and sequenced in order to design primers that would amplify only the target fragment. The derived sequence characterized amplified region (SCAR) markers SB17645 and SV01574 (645 and 574 bp, respectively) were present only in the resistant parent. The SV061092 marker amplified a band of 1092 bp only in the susceptible parent. These markers are more universal than the CAPS markers developed by Brotman et al. (Theor Appl Genet 10:337–345, 2005). The analysis of 24 melon accessions, representing several melon types, with these markers revealed that different melon types behaved differently with the developed markers supporting the theory of multiple, independent origins of resistance to races 0 and 2 of F.o.m.

Dielectric Spectroscopy of Melons for Potential Quality Sensing

Several cultivars of cantaloupe, honeydew melons, and watermelons were planted and harvested with a range of maturities for dielectric properties measurements and moisture and soluble solids content (SSC) determination. Permittivities (dielectric constants and dielectric loss factors) were determined over the frequency range from 200 MHz to 20 GHz with an open-ended coaxial-line probe and network analyzer for both interior tissue and surface measurements. Permittivity data are presented graphically for all three types of melons. High correlations were noted between SSC and moisture content in the tissues of all three kinds of melons, with SSC increasing linearly with decreasing moisture content of the edible tissues. Dielectric properties determined by measurements on the external surface of the melons had lower values than those of the internal tissues. Dielectric properties were similar for all three melon types, and they reflect the influence of the dielectric behavior of free water. No obvious correlations were noted between the dielectric properties and the SSC (sweetness) for sensing the quality of the melons.

Melon Fruits: Genetic Diversity, Physiology, and Biotechnology Features

Among Cucurbitaceae, Cucumis melo is one of the most important cultivated cucurbits. They are grown primarily for their fruit, which generally have a sweet aromatic flavor, with great diversity and size (50 g to 15 kg), flesh color (orange, green, white, and pink), rind color (green, yellow, white, orange, red, and gray), form (round, flat, and elongated), and dimension (4 to 200 cm). C. melo can be broken down into seven distinct types based on the previously discussed variations in the species. The melon fruits can be either climacteric or nonclimacteric, and as such, fruit can adhere to the stem or have an abscission layer where they will fall from the plant naturally at maturity. Traditional plant breeding of melons has been done for 100 years wherein plants were primarily developed as open-pollinated cultivars. More recently, in the past 30 years, melon improvement has been done by more traditional hybridization techniques. An improvement in germplasm is relatively slow and is limited by a restricted gene pool. Strong sexual incompatibility at the interspecific and intergeneric levels has restricted rapid development of new cultivars with high levels of disease resistance, insect resistance, flavor, and sweetness. In order to increase the rate and diversity of new traits in melon it would be advantageous to introduce new genes needed to enhance both melon productivity and melon fruit quality. This requires plant tissue and plant transformation techniques to introduce new or foreign genes into C. melo germplasm. In order to achieve a successful commercial application from biotechnology, a competent plant regeneration system of in vitro cultures for melon is required. More than 40 in vitro melon regeneration programs have been reported; however, regeneration of the various melon types has been highly variable and in some cases impossible. The reasons for this are still unknown, but this plays a heavy negative role on trying to use plant transformation technology to improve melon germplasm. In vitro manipulation of melon is difficult; genotypic responses to the culture method (i.e., organogenesis, somatic embryogenesis, etc.) as well as conditions for environmental and hormonal requirements for plant growth and regeneration continue to be poorly understood for developing simple in vitro procedures to culture and transform all C. melo genotypes. In many cases, this has to be done on an individual line basis. The present paper describes the various research findings related to successful approaches to plant regeneration and transgenic transformation of C. melo. It also describes potential improvement of melon to improve fruit quality characteristics and postharvest handling. Despite more than 140 transgenic melon field trials in the United States in 1996, there are still no commercial transgenic melon cultivars on the market. This may be a combination of technical or performance factors, intellectual property rights concerns, and, most likely, a lack of public acceptance. Regardless, the future for improvement of melon germplasm is bright when considering the knowledge base for both techniques and gene pools potentially useable for melon improvement.

Sensory evaluation of ‘Galia’-type melons treated with 1-methylcyclopropene after prolonged storage

SummaryExposure to 300 nl l–1 1-methylcyclopropene (1-MCP) suppresses internal and external ripening parameters in melons harvested at the green/yellow stage of maturity. We investigated the sensory attributes and volatiles of ‘Galia’-type melons treated with the ethylene activity inhibitor 1-MCP at the green/yellow stage of ripening, compared to untreated and commercially-treated fruit after prolonged storage. Organoleptic and volatile analyses were performed after 15 d storage at 5°C and a 3 d marketing simulation at 20°C. 1-MCP-treated fruit had a lower level of total volatiles (3,334 µg kg–1 FW) compared to untreated fruit, or to fruit washed and waxed according to commercial practice. Most of the volatiles were esters, while a few were aldehydes, or ethanol. Methyl acetate, as well as methyl 2-methylbutanoate, which are associated with the ‘fruity’ aroma note, were significantly higher in 1-MCP-treated fruit. The “green” note, due to hexanal, remained relatively high in 1-MCP-treated fruit after storage, while it was not detected in commercially-treated fruit. Ethanol, ethyl acetate, and ethyl hexanoate volatiles that are associated with “off-flavour” and over-ripening were significantly higher in commercially-treated fruit. A trained panel described the sensory properties of the three treatments. The overall aroma notes were significantly more intense in commercially-treated fruit, while in 1-MCP-treated fruit they were much less evident. 1-MCP-treated fruit had the strongest “green” note, while commercially-treated fruit had the weakest. A very strong ‘acetone’ note was detected after commercial treatment, and was associated with ‘unpleasant’ and ‘non-typical’ notes. Members of an untrained panel preferred 1-MCP-treated melon and disliked commercially-washed and waxed fruit.

Morphological diversity of current melons (Cucumis melo) compared to a medieval type

Morphological diversity of melon (Cucumis melo); phenotype reconstruction of a medieval sample. Morphological diversity among 47 melon (Cucumis melo) cultivars and landraces from Hungarian germplasm collection (ABI, Tápiószele) were analyzed with an ultimate aim to characterize morphologically cv. Hógolyó, which showed the closest genetic similarity to a medieval melon recovered from the 15th century. Cultivars based on fruit morphology were grouped into the three main types of melon as reticulatus, cantalupensis and inodorus. Cluster analysis (by SPSS-11) based on 23 morphological (quantitative and qualitative) traits recorded revealed an extreme diversity among accessions, nevertheless cultivars were clustered into main melon clusters with only two exceptions of inodorus type cv. Zimovka J. and Afghanistan. Cultivars Sweet ananas and Ezüst ananász; and two Hungarian landraces Kisteleki and Nagycserkeszi showed close similarity. Cultivars Hógolyó and Túrkeve of inodorus typewere also grouped in one cluster, which provide insight into the morphological reconstruction of the medieval melon recovered from the 15th century. These results also indicate that old Hungarian landraces could be re-introduced into breeding programs for broadening genetic base of melon.

GENETIC DIVERSITY OF CHINESE THIN-SKINNED MELON CULTIVARS (CUCUMIS MELO L.) BASED ON SIMPLE SEQUENCE REPEAT MARKERS**

ISHS XXVII International Horticultural Congress - IHC2006: International Symposium on Structural and Functional Genomics of Horticultural Plants GENETIC DIVERSITY OF CHINESE THIN-SKINNED MELON CULTIVARS (CUCUMIS MELO L.) BASED ON SIMPLE SEQUENCE REPEAT MARKERS**

Effect of hot water treatment and various calcium salts on quality of fresh-cut ‘Amarillo’ melon

Microbial growth and firmness loss in fresh-cut melon are the main problems associated with quality loss, even under cold storage. ‘Amarillo’ melon ( Cucumis melo var. saccharinus Naud), a new important type of melon for the fresh-cut industry, was minimally processed in trapezoidal sections and dipped in 0.5% Ca chloride for 1 min at 5 °C or 60 °C. Sterile distilled water (with no Ca salt) was used as a control. After dipping, fresh-cut melon was packaged in sealed trays using micro-perforated film and kept for 8 days at 5 °C. Hot (60 °C) Ca dips increased bound Ca levels, maintained the firmness, reduced the microbial growth and improved sensory quality compared to control treatments and those treated with Ca at 5 °C. In a second experiment, hot dips using different Ca salt solutions (Ca chloride, Ca carbonate, Ca lactate and Ca propionate) were studied using a Ca concentration equivalent to 0.5% Ca chloride (0.18 g Ca 100 mL −1). Softness of cut melon was related to bound Ca concentration: at higher bound Ca concentrations tissue firmness was improved. Ca chloride, lactate and propionate increased the bound Ca levels by 50% and also maintained firmness of the fruit pieces. However, control and Ca carbonate treatments decreased firmness by 27% and 19%, respectively. In the control melon samples, mesophilic and psychrotrophic bacterial counts were 6 and 7.3 log cfu g −1, respectively. Ca dips reduced microbial counts by about 2 (Ca chloride and Ca lactate) or 4 (Ca propionate) log units. Ca propionate decreased metabolic activity but imparted a slight off-flavour to the cut melon, and therefore, lower Ca propionate concentrations must be studied to avoid this off-flavour. No Ca dip induced a salty or bitter taste. The effect of Ca on fresh-cut melon quality depended on the type of Ca salts. Ca chloride, and especially weak organic acid salts like Ca propionate and lactate, was very effective in reducing microbial growth and maintaining fruit firmness during 8 days storage at 5 °C.

First Report of Verticillium Wilt of Watermelon in the Texas High Plains.

Verticillium dahliae (Kleb.) is known worldwide as a destructive soilborne pathogen with a wide host range (2). Reports of V. dahliae attacking cucurbits are generally limited to 'Casaba' and 'Persian' type melons. During August and September of 2004 to 2006, fields of seedless watermelon (Citrullus lanatus [Thunb.] Matsum. & Nak.) and pollinators in Yoakum County, Texas, exhibited severe symptoms of vine decline. There was no apparent difference between diploid and triploid watermelon cultivars. Night-time temperatures during July, August, and September averaged 20°C or less. Losses were estimated in excess of one-half million dollars. Symptoms consisted of leaf yellowing, wilting, and gradual death of the leaves, but stems generally remained green. The xylem exhibited a uniform tan-to-light brown discoloration that often extended throughout the vine. Dead plants had numerous microsclerotia embedded throughout the root and crown. Crown and root sections (1 cm long) from triploid plants were surface disinfected in 0.5% NaOCl for 30 s, transferred to water agar with 100 ppm of streptomycin sulfate, and incubated at 25°C. Slow-growing colonies were transferred to potato dextrose agar after approximately 72 h. V. dahliae was identified on the basis of morphology (3). Pathogenicity of four selected isolates was determined on the watermelon cultivars used to identify races of Fusarium oxysporum f. sp. niveum (Fon). Flasks containing 100 ml of medium (1) were inoculated with a 1-ml spore suspension at 1 × 105 spores/ml for each isolate and placed on an orbital shaker for 6 days at 100 rpm with continuous near-UV/fluorescent lighting at 25°C. Roots of approximately 40 plants of each of five watermelon cultivars (1 to 2 true-leaf stage) were trimmed to 2 cm long and root dipped for 2 min in the spore suspension (1 × 106/ml) of each isolate. Each cultivar/isolate combination and controls were transplanted into 10 pots (1.5 liter) with four plants per pot. The pots were transferred to the greenhouse where soil temperatures ranged between 15 and 25°C and were fertilized (Jack's fertilizer solution) every 7 days. Plants were rated at the end of 28 days as 1 = healthy, 2 = stunting (≤50% of controls), 3 = wilting, and 4 = dead. Initial wilting was observed within 7 to 10 days postinoculation. All four isolates caused varying degrees of vascular discoloration, stunting, wilting, and plant death. The pathogen was reisolated from symptomatic plants but not the controls. Mean disease ratings for the most virulent Texas isolate (28-040215) on 'Black Diamond', 'Charleston Gray', 'Dixie Lee', 'Calhoun Gray', and 'PI 296341 FR' were 2.7, 3.0, 3.0, 2.9, and 2.9, respectively. All watermelon Fon differentials were equally susceptible to V. dahliae in these studies. Historically, Verticillium wilt has been a problem in this area, which has been in cotton production for approximately 100 years. In the past decade, watermelon production has increased substantially to approximately 3,600 ha in the Texas High Plains. To our knowledge, this is the first known report of Verticillium wilt on watermelon in Texas.

Widespread Outbreak of Cucurbit yellow stunting disorder virus in Melon, Squash, and Watermelon Crops in the Sonoran Desert of Arizona and Sonora, Mexico.

Bright yellow, interveinal chlorosis was observed for the first time on leaves of the older and mid-growth of cucurbit plants in southern Arizona and Sonora (Mexico) during September and October of 2006. Some cultivars exhibited substantial yield losses of 30 to 80%. In Arizona, symptoms were in Cucumis melo (muskmelon and honeydew melon) fields in the Yuma Valley and Hyder. In Sonora, honeydew and muskmelon, Cucurbita pepo (acorn, spaghetti, and summer [yellow and zucchini] squash), and Citrullus lanatus (watermelon) were symptomatic in Hermosillo, whereas, in Caborca, honeydew and cantaloupe developed similar symptoms. Interveinal chlorosis was observed in 60 to 100% of the plants in each field. Crops planted mid-to-late season were 100% infected, whereas, the early-season fields experienced approximately 60 to 80% incidence. All symptomatic fields in the Sonoran Desert and vicinity were infested by the whitefly Bemisia tabaci (Genn.), which was identified as the 'B biotype' on the basis of mitochondria COI sequence analysis (data not shown). Whitefly population levels were variable and ranged from 5 to 200 per plant. Total RNA was isolated from leaf samples collected from symptomatic plants using Tri Reagent (Molecular Research Center, Cincinnati, OH). Purified RNA was used in reverse transcriptase-PCR with primers specific to the Cucurbit yellow stunting disorder virus (CYSDV) coat protein (CP) gene (RNA2-deoxyribonucleotide coordinates 4927-4950 and 5657-5679) for the suspected whitefly-transmitted bipartite CYSDV (4). PCR yielded the CYSDV CP fragment, at 753 bp (GenBank Accession Nos. EF21058 and EF21059), which was cloned into pGEM T-Easy and sequenced in both directions using universal primers. The CYSDV CP nucleotide sequences (n = 16) obtained from acorn squash, honeydew melon, muskmelon, yellow squash, and watermelon had 99 to 100% identity. The Arizona (AZ) and Sonora (SON) CYSDV CP sequences shared 99 to 100% identity with previously described CYSDV isolates from the Eastern Hemisphere (GenBank Accession Nos. DQ903105 and DQ903108) and also with two isolates of CYSDV collected during 2004 from Zacapa Valley, Guatemala (GenBank Accession Nos. EF21060 and EF21061) (J. K. Brown, unpublished data). CYSDV is a member of the genus Crinivirus, family Closteroviridae. CYSDV was first identified in cucumber and melon crops in the Middle East approximately 15 years ago and 10 years ago in Spain (1). Most recently, this virus was introduced into Texas (2), Guatemala (J. K. Brown, unpublished data), and Arizona and California (3). CYSDV has therefore emerged as an important and potentially worldwide threat to the production of cultivated cucurbits (3). The threat appears to be significant in light of the introduction or establishment of the exotic B. tabaci biotypes B and Q vectors, which also originated in the Middle Eastern-North African-Mediterranean region. To our knowledge, this is the first report of CYSDV infecting field-grown C. pepo (four types) and watermelon, reported previously only as experimental laboratory hosts, and of CYSDV in two types of melon (C. melo) in Mexico.

Nutritional values of traditional open-pollinated melon (Cucumis melo L.) and watermelon (Citrullus lanatus [Thumb]) varieties

The aim of our experiments was to investigate the internal quality parameters of some old melon and watermelon landraces or varieties whether they have any desirable characteristics. Measurements were carried out using 8 different types of melon (Cucumis melo L.) and 8 accessions of watermelon (Citrullus lanatus [Thumb]), which were self pollinated under greenhouse conditions. Besides the determination of dry matter content; soluble solids, titratable acidity of the fruit juices, investigation of carbohydrates, total phenol content was measured by spectrophotometer. Total antioxidant capacities were determined spectrophotometrically using the FRAP method. We found some accesions both among melon and watermelon varieties, which could be characterized by outstanding inner content.

Detection of QTL for yield-related traits using recombinant inbred lines derived from exotic and elite US Western Shipping melon germplasm

The inheritance of yield-related traits in melon (Cucumis melo L.; 2n = 2x = 24) is poorly understood, and the mapping of quantitative trait loci (QTL) for such traits has not been reported. Therefore, a set of 81 recombinant inbred lines (RIL) was developed from a cross between the monoecious, highly branched line USDA 846-1 and a standard vining, andromonoecious cultivar, 'Top Mark'. The RIL, parental lines, and three control cultivars ('Esteem', 'Sol Dorado', and 'Hales Best Jumbo') were grown at Hancock, WI and El Centro, CA in 2002, and evaluated for primary branch number (PB), fruit number per plant (FN), fruit weight per plant (FW), average weight per fruit (AWF), and percentage of mature fruit per plot (PMF). A 190-point genetic map was constructed using 114 RAPD, 43 SSR, 32 AFLP markers, and one phenotypic trait. Fifteen linkage groups spanned 1,116 cM with a mean marker interval of 5.9 cM. A total of 37 QTL were detected in both locations (PB = 6, FN = 9, FW = 12, AWF = 5, and PMF = 5). QTL analyses revealed four location-independent factors for PB (pb1.1, pb1.2, pb2.3, and pb10.5), five for FN (fn1.1, fn1.2, fn1.3, fn2.4, and fn8.8), four for FW (fw5.8, fw6.10, fw8.11, and fw8.12), two for AWF (awf1.3 and awf8.5), and one for PMF (pmf10.4). The significant (P </= 0.05) positive phenotypic correlations observed among PB, FN, and FW, and negative phenotypic correlations between PB and AWF and between FN and AWF were consistent with the genomic locations and effects (negative vs. positive) of the QTL detected. Results indicate that genes resident in highly branched melon types have potential for increasing yield in US Western Shipping type germplasm via marker-assisted selection.

Controle biológico de Monosporascus cannonballus com Chaetomium

O colapso do meloeiro (Cucumis melo), causado por Monosporascus cannonballus, é uma das principais enfermidades que acometem esta olerícola. O presente trabalho objetivou estudar o potencial do controle biológico de M. cannonballus com Chaetomium. Substrato infestado com 0,5; 1; 2; 4 e 8 x 10(5) UFC g-1 de Chaetomium foi colocado em bandejas, nas quais sementes de meloeiro do tipo Pele de Sapo cv. PS 1430 foram semeadas após duas semanas de incubação. As mudas obtidas foram transplantadas para vasos com substrato semelhante, sendo que neste momento o substrato foi infestado com mais 2,5 x 10(4) UFC g-1 de Chaetomium por vaso e 20 UFC g-1 de substrato de M. cannonballus. Três testemunhas foram utilizadas, uma infestada apenas com Chaetomium, outra somente com M. cannonballus e testemunha absoluta. O delineamento estatístico foi inteiramente casualizado com cinco repetições. As avaliações foram efetuadas aos 45 dias após o transplante, sendo calculado o índice geral de doença e o percentual de controle. O valor do índice geral de doença variou conforme o aumento da concentração de Chaetomium, sendo os menores valores encontrados para os tratamentos 4 e 8 x 10(5) UFC g-1de Chaetomium equivalentes a 0,9 e 0,6, respectivamente. A análise estatística demonstrou que os tratamentos correspondentes a 4 e 8 x 10(5) UFC g-1 de Chaetomium foram mais eficientes, diferindo dos demais, com percentual de controle superior a 55 %, evidenciado o potencial de Chaetomium no controle de M. cannonballus.

Evaluation of genetic diversity in Turkish melons (Cucumis melo L.) based on phenotypic characters and RAPD markers

The genetic relationships among 56 melon (Cucumis melo L.) genotypes collected from various parts of Turkey were determined by comparing their phenotypic and molecular traits with those of 23 local and foreign melon genotypes to investigate the taxonomic relationships and genetic variation of Turkish melon germplasm. Sixty-one phenotypic characters and 109 polymorphic RAPD markers obtained from 33 primers were used to define the genetic similarity among the melon genotypes by dendrograms or two and three dimensional scaling. There were high correlations (r ≥ 0.97) among the four resulting matrices used in molecular characterization. The correlations between phenotypic (Euclidean) and molecular Euclidean, Jaccard, Simple matching, and Nei analyses were r = 0.41, r = −0.40, r = −0.43 and r = −0.40, respectively. Related genotypes or genotypes collected from similar regions were partitioned to similar clusters. Both analyses (phenotypic and molecular) indicated that non-sweet melon types were dissimilar from sweet types and diversity of Turkish melon genotypes was higher than that of sweet foreign cultivars examined, but similar to that of the reference accessions employed. It was also observed that sweet Turkish melon genotypes belonging to groups inodorus and group cantalupensis were highly variable and could have intermated or have crossed with other non-sweet types.

INFLUENCE OF POST-HARVEST TREATMENTS ON QUALITY OF GALIA MELONS DURING LOW TEMPERATURE STORAGE

A new post-harvest treatment for ‘Galia’-type melons has been developed for simultaneously clearing and disinfecting using hot water and brushes. Pre-storage heat treatment appears to be one of the most promising in post-harvest control decay. The efficiency of HWRB treatment was dependent on the temperature used and time of exposure. Fruits were placed on rotating brushes and rinsed with tap water followed by a hot water rinse (HWRB) at 50, 54, 58 and 60 ±1°C for 15 sec. The fruits were removed from the cartons and hand-sprayed until completely coated hand-sprayed with Zivdar wax (Safepack, Raanana, Decco, Israel) for melons, containing 2% (w/v) sodium bicarbonate (SBS) incorporated into wax represented the current commercial treatment. After drying, melons were repacked in the cartons and stored for 14 days at 2°C and 5°C and up to 5 days at 20°C (shelf life during retail and marketing). The optimal treatment to reduce decay while maintain fruit quality after prolonged storage and marketing simulation was 60 ±1°C for 15 sec. Treatment includes hot water drenching (60°C for 10-15 sec) applied while the fruit is rolling on soft brushes and followed by coating with a wax preparation containing 2% sodium bicarbonate. The efficacy of the new post-harvest practice (hot water washing, coating with wax preparation containing sodium bicarbonate) was confirmed in Galia melons. This practice improved the general appearance and reduced post-harvest decay while maintaining fruit quality.

Qualidade dos frutos de tipos de melão,produzidos em ambiente protegido

O interesse pela cultura do melão no Brasil tem aumentado muito nos últimos anos, pelas crescentes exportações e pelo incremento no consumo do mercado interno. O objetivo deste trabalho foi avaliar as características físicas e químicas, assim como a atividade da pectinametilesterase dos frutos de tipos de melão (Cucumis melo L.), produzidos em ambiente protegido, no município de Centenário do Sul-PR. Os tipos estudados foram: Valenciano ('Amarelo-Ouro'), Caipira ('Gaúcho Caipira'), Net Melon ('Net Galia'), Orange ('Orange Melon') e Pele-de-Sapo ('Filipo'), com cinco repetições, utilizando seis frutos por repetição em delineamento inteiramente casualizado. Os frutos do Valenciano e Pele-de-Sapo destacaram-se quanto à massa, com valores 2,02 e 2,07 kg, respectivamente, e formatos alongados, enquanto os demais tipos apresentaram formatos arredondados e massa em torno de 1,4 kg. Os melões Pele-de-Sapo apresentaram espessura da polpa de 43,36 mm, estatisticamente superior à dos frutos Valenciano, com 38,98 mm. A menor espessura de polpa, 24,78 cm, e a maior espessura de casca, 9,74 mm, foram encontradas nos frutos do tipo Caipira que diferiu estatisticamente dos outros tipos. Os valores de pH não se apresentaram estatisticamente diferentes e variaram de 6,24 a 6,48. O Net Melon apresentou polpa com 12,3ºBrix e diferiu estatisticamente do Orange, Valenciano e Pele-de-Sapo, com 11;12; 10,34 e 9,94 ºBrix, respectivamente. O Caipira atingiu 5,06ºBrix, e também o menor conteúdo de acidez, 0,10 g de ac. cítrico.100-1 g de suco, o que inviabiliza sua comercialização. A atividade da pectinametilesterase na polpa dos frutos foi muito baixa, inferior a 0,005 PEu x 10(4) mL-1, nos cinco tipos avaliados. Na região norte do Paraná (Vale do Paranapanema), sob condições de cultivo protegido, os melões Pele-de-Sapo, Net Melon, Orange e Valenciano apresentaram boas características físicas e químicas dos frutos, destacando-se o Net Melon pelo teor de sólidos solúveis totais, acima de 12ºBrix.

Market Quality Attributes of Orange-fleshed, Non-netted Honey Dew Melon Genotypes Following Different Growing Seasons and Storage Temperature Durations

Orange-fleshed honey dew (Cucumis melo L., Inodorus group) fruit are known for having superior food-safety, food-quality, and fruit-marketability attributes compared with orange-fleshed netted muskmelon (C. melo, Reticulatus group) and to green-fleshed honey dew (C. melo, Inodorus group) fruit. However, little is known about the production market attributes and postharvest quality comparisons of the leading orange-fleshed honey dew cultivars. Five orange-fleshed honey dew genotypes (‘Honey Gold’, ‘Orange Delight’, ‘Orange Dew’, ‘Temptation’, and a breeding line) were glasshouse-grown in both fall and spring, harvested at abscission (full-slip), and compared after storage for 3–24 days in air at 5 or 10 °C. Fruit maturity (full-slip) was between 31 and 38 days after anthesis, with maturation dependent on genotype. Days to maturity were slightly longer in the fall than in the spring. Fruit size (number of fruit per standard commercial shipping box) was between four and six fruit per box. ‘Orange Dew’ consistently had the smallest fruit (six per box), and the breeding line had the largest (four per box). ‘Orange Delight’ and ‘Orange Dew’ had the fewest whole-fruit disorders and the highest percentage of marketable fruit at harvest and following 24 days of storage at 5 or 10 °C. ‘Orange Delight’, ‘Orange Dew’, and the breeding line consistently had a more yellow peel, whereas ‘Honey Gold’ and ‘Temptation’ fruit peels had a more greenish hue. Whole-fruit firmness was 10–25 N among the cultivars and 24–35 N for the breeding line. Internal-fruit disorders, percentage marketability, and mesocarp (pulp) firmness reflected each genotype's whole-fruit attributes. ‘Orange Delight’ and ‘Orange Dew’ fruit consistently had among the highest soluble solids concentration and relative sweetness ratings, and their pulp had a more intense orange hue and lower lightness than those of the other genotypes. After 24 days of storage, ‘Orange Delight’ and ‘Orange Dew’ maintained their higher sweetness and more orange hue in both spring and fall harvests; however, depending on harvest, they were not always significantly sweeter or more orange-hued than some of the other genotypes. Our results indicate that orange-fleshed honey dew fruit are a promising new melon type suitable as a substitute for orange-fleshed netted muskmelon fruit not only for food-safety issues but also for overall marketable quality.

Sensory and analytical comparison of orange-fleshed honeydew to cantaloupe and green-fleshed honeydew for fresh-cut chunks

Maintaining the sensory, microbial and postharvest quality of fresh-cut fruit after processing and throughout distribution and marketing is a major challenge facing the fresh-cut fruit industry. Fresh-cut chunks of orange-fleshed honeydew (‘Honey Gold’, ‘Orange Dew’, ‘Temptation’ and three breeding lines) and green-fleshed honeydew (‘Honey Brew’) and an orange-fleshed cantaloupe (‘Cruiser’) harvested at commercial and full-slip maturities were compared after storage for 0–11 days in air at 5 °C. Fresh-cut cantaloupe had higher respiration and ethylene production rates, aromatic volatile concentrations, and β-carotene/chroma and orange hue (except ‘Orange Dew’) than those of honeydew whereas honeydew chunks generally had higher soluble solids content (SSC), Kramer firmness and lower microbial counts than cantaloupe chunks. All genotypes had similar ascorbic acid levels. During storage, analytical quality characteristics of fresh-cut chunks from all genotypes were well maintained even though microbial populations increased especially on cantaloupe chunks. Consumers liked the flavor, texture, sweetness and overall eating quality of the orange-fleshed honeydew genotypes as well as or better than those of cantaloupe and green-fleshed honeydew. ‘Orange Dew’ scored highest in appearance and had the highest β-carotene concentration, chroma and orange hue among orange-fleshed honeydew genotypes whereas ‘Temptation’ generally scored highest for flavor intensity and acceptability and overall eating quality; and it had the highest aromatic volatile concentrations among the orange-fleshed honeydews. Many individual volatiles were identical in cantaloupe and honeydews; however, honeydew genotypes, particularly ‘Temptation’, were distinctive from cantaloupe and green-fleshed honeydew in having relatively high levels of various nonenyl and nonadienyl acetates having honeydew-like or uncharacterized aromas. Fresh-cut chunks from full-slip melons generally had higher analytical and sensory quality characteristics but higher microbial counts and lower shelf stability compared to those from commercially mature fruit. The results indicate that orange-fleshed honeydews are a promising new melon type for fresh-cut processing.

Molecular characterization of South and East Asian melon, Cucumis melo L., and the origin of Group Conomon var. makuwa and var. conomon revealed by RAPD analysis

The genetic diversity and relationship among South and East Asian melon Cucumis melo L. were studied by using RAPD analysis of 69 accessions of melon from India, Myanmar, China, Korea, and Japan. The genetic diversity was large in India, and quite small in Group Conomon var. makuwa and var. conomon from East Asia, clearly indicating a decrease in genetic variation from India toward the east. Cluster analysis based on genetic distance classified 17 groups of accessions into two major clusters: cluster I comprising 12 groups of accessions from India and Myanmar and cluster II that included five groups of accessions of Group Conomon var. makuwa and var. conomon from East Asia. Cluster I was further divided into three subclusters, of which subclusters Ib and Ic included small- and large-seed type populations, respectively. Therefore, this division was based on their seed size, not cultivation area. The large-seed type from east India was differently included in the subcluster of small-seed type (Ib). A total of 122 plants of 69 accessions were classified into three major clusters and subclusters: clusters I and II comprised melon accessions mostly from India and Myanmar, and cluster III comprised Group Conomon var. makuwa and var. conomon from East Asia. The frequency of large- and small-seed types was different between clusters I and II, also indicating genetic differentiation between large- and small-seed types. One plant of the small-seed type from east India was differently included in cluster III, and two plants from east India were classified into subcluster IV. These results clearly showed that South Asian melon is genetically differentiated by their seed size, and that small-seed type melon in east India is closely related to Group Conomon var. makuwa and var. conomon.