Muskmelon Cultivars Research Articles

Cultivar effect on proximal optical sensor measurements and estimation of leaf N content in muskmelon and sweet pepper

In intensive vegetable crops, there is a requirement for monitoring tools that assess crop nitrogen (N) status to reduce N use and the potential for nitrate (NO3-) leaching loss. Monitoring with proximal optical sensors can regularly provide information to vegetable growers to assist with optimal crop N management. Reference values for proximal optical sensor measurements that indicate crop N sufficiency or deficiency are increasingly available in the literature. Available values are species specific; however, their use may be problematic if proximal optical sensor measurements are affected by cultivar. Little is known on whether differences between cultivars, within a species, affect optical sensor measurements and their relationships with crop N status, particularly in vegetable crops. This study evaluated the effect of cultivar on a) measurements with the SPAD-502 chlorophyll meter, Normalized Difference Vegetation Index (NDVI) measured with the Crop Circle ACS 470 canopy reflectance sensor, and Nitrogen Balance Index (NBI-R) measured with the Multiplex fluorimeter, and b) the relationships of these measurements with leaf N content. The study was conducted with four cultivars of muskmelon (Tezac, Bosito, Magiar and Jacobo) and three of sweet pepper (Melchor, Machado and CLX PLRJ 731). In both muskmelon and sweet pepper, there were significant differences between cultivars in SPAD and in NBI-R. The range of differences between the cultivars was 2.2−9.7 and 0.6−2.8 SPAD units in muskmelon and sweet pepper, respectively, and 0−0.16 and 0.020.08 NBI-R units in muskmelon and sweet pepper, respectively. Significant differences between cultivars in the NDVI were only obtained in muskmelon; the range of differences between the four cultivars was 0.01–0.04 NDVI units. The relatively large cultivar effect with SPAD and NBI-R values with muskmelon may limit the use of reference values in this species. For avoiding cultivar effects in the two species evaluated, NDVI is preferrable to SPAD and NBI-R. In general, the slopes and intercepts of linear relationships between optical sensor measurements and leaf N content, for each cultivar of each species, were not significantly different to the slope and intercept of the relationship calculated with pooled data of all cultivars of each species. This indicated that the sensitivity of optical sensors to assess leaf N content was similar between cultivars of each species.

Genetic characterization of new source of resistance for tomato leaf curl New Delhi virus (ToLCNDV) from snapmelon (C. melo var. momordica)

AbstractThis study aimed to understand the genetics of tomato leaf curl New Delhi virus (ToLCNDV) in the identified novel source of resistance from Indian melon germplasm DSM-19 (Cucumis melo var. momordica) as viral diseases in muskmelon cause significant economic yield loss. To achieve this, a cross was made between the highly susceptible genotype Pusa Sarda (C. melo var. inodorus), known for its desirable fruit characters, and the resistant source DSM-19 to generate the suitable populations for inheritance study. These populations were screened under natural epiphytotic conditions and further validated through challenge inoculation with viruliferous whiteflies. The inheritance of ToLCNDV resistance in snapmelon germplasm DSM-19 was identified as monogenic recessive in both the screening methods. Moreover, a cleaved amplified polymorphic sequence (CAPS) marker named ‘CAPS 16 (2)’ was designed near to SNP marker D16 located on chromosome 11 of melon, and it was found to be linked to the ToLCNDV resistance gene in DSM-19. This is the first report on genetics of ToLCNDV resistance in snapmelon germplasm from India. Snapmelon line DSM-19 can be used as a source for fine mapping and introgression of the ToLCNDV resistance into susceptible muskmelon cultivars.

Determination of healthy natural antioxidants in selected muskmelon (Cucumis melo) cultivars

Muskmelon (Cucumis melo L.) is a popular summer fruit consumed all over the world due to the combination ofrefreshingly sweet taste, pleasant flavour and nutritional value. Melon fruit is characterized by germplasm variabilitywith superior quality. This study aimed to evaluate 5 promising local muskmelon cultivars (Maazoun, Galaoui,Stambouli, Trabelsi, Asli) for some physicochemical characteristics, the content of different bioactive compoundsand the antioxidant activity. The experiments were conducted for two consecutive years 2018 and 2019 at the support station of the inter-professional vegetable group positioned in the North East of Tunisia. Significant differences were observed across the melon cultivars (P<0.05) for soluble solids (9–12°Brix), pH (5.5–6.6), carotenoid (7.5–59.5 mg/ kg FW), phenolic (400–1390 mg GAE/kg FW), flavonoid (251.3–390 mg RE/kg FW), vitamin C (138.2–193 mg/kg FW) contents, as well as hydrophilic (102.28–285.43 μM Trolox/100 g FW) and lipophilic (30–180.22 μM Trolox/100 g FW) antioxidant activities. Galaoui showed the highest levels of carotenoids, phenolics, flavonoids, vitamin C and antioxidant activities followed by Stambouli. Trabelsi cultivar also had a high level of flavonoids. The enhanced hydrophilic antioxidant activity in Galaoui was significantly correlated to phenolic content (r = 0.91). These findings proved that besides being refreshing summer fruit, muskmelon can be considered a promising healthy produce with a superior potential source of natural antioxidants.

Changes in Pectic Substances and Cell Wall Degrading Enzymes During Muskmelon Fruit Ripening

Changes in pectic substances and the activities of the cell walldegrading enzymes, pectin esterase (PE) and polygalacturonase (PG) wereevaluated during muskmelon fruits ripening. Respiration rateprogressively increased in a climacteric pattern. Fruit flesh firmnesssteadily declined and rind yellow colour increased during ripening. Totaland insoluble pectins progressively decreased, while the soluble pectinsincreased with fruit ripening. Positive correlation coefficients wereobtained between total and insoluble pectins, and fruit flesh firmness.Total protein and PE activity increased up to the climacteric peak ofrespiration and decreased afterwards. PG activity progressively increasedduring fruit ripening, with high correlation between the increase inenzyme activity and fruit softening in the three muskmelon cultivars. Thismay indicate that the two enzymes polygalacturonase (PG) and pectinesterase (PE) are the main enzymes responsible for fruit softening duringmuskmelon fruit ripening.

Compositional Changes during Muskmelon Fruit Ripening

The objective of this study was to investigate compositionalchanges during ripening of three Galia F1 muskmelon cultivars for export;namely, ‘Galeb’, ‘Seeren’ and ‘Green Star’ at 18±1ºC and 85%-90%relative humidity. The fruits of the three cultivars exhibited a typicalclimacteric pattern of respiration during ripening. Fruit flesh firmness wasdeclined progressively in a similar manner in the three cultivars. Rindcolour, total soluble solids (TSS) and weight loss steadily increased andcellulose content decreased with fruit ripening. Total protein increased upto the climacteric peak of respiration and then decreased.

Comparative analysis of volatile compounds in different muskmelon cultivars in Xinjiang based on HS-SPME-GC-MS and transcriptomics

Comparative analysis of volatile compounds in different muskmelon cultivars in Xinjiang based on HS-SPME-GC-MS and transcriptomics

PRICE TRANSMISSION OF MELONS (CUCUMIS MELO AND CITRULLUS LANATUS) IN MYANMAR – CHINA BORDER TRADE

Border trade is the main export channel for agricultural products from Myanmar (formerly Burma). With an increasing quantity and value of exports during the last few decades, melons have become one of the major crops in the national export strategy of Myanmar. In this paper, the word “melons” is used to represent both watermelon (Citrullus lanatus) and muskmelon (Cucumis melo) cultivars. No previous research exists on price transmission between these countries, especially for the horticultural produce market. This study aims to measure the magnitude and speed of spatial price adjustment in melons exported from Myanmar to China. Price transmission in the melon export market in Myanmar is analyzed by studying the lead-lag relationship among prices in the border market in Myanmar and the selected wholesale markets in Beijing, China, using a vector autoregressive model (VAR). Prices are transmitted quickly from Myanmar to the selected wholesale markets in Beijing, China. The wholesale market price in Beijing, China lags only one day behind the Myanmar price. In the Myanmar border market, the melon price is affected only by its own lagged price. The adjustment of melon prices in one day suggests that market information is getting passed up the market channel, and there does not appear to be a need for a policy to improve market efficiency.

Screening of rootstocks with resistance to chilling and continuous cropping but without compromising fruit quality for protected watermelon production

Chilling stress and continuous cropping obstacles limit sustainable production of watermelons under controlled environments. Grafting of watermelon scions onto resistant rootstocks is an effective strategy currently used to overcome these environment limitations. However, currently used commercial rootstocks adversely affect watermelon fruit quality. The chilling tolerance and <italic>Fusarium oxysporum</italic> f. sp. <italic>niveum</italic> race 1 (FON1) resistance of seven Cucurbit germplasms, including four watermelon germplasms (M08, TC, YL, and MY), two muskmelon cultivars (JT1 and JSM), and one commercial Cucurbita rootstock (QZ1) of watermelon, were explored in the current study. The effects of the rootstocks of these germplasms on watermelon resistance to chilling stress and continuous cropping obstacles were evaluated. TC rootstock showed the highest chilling tolerance and increased chilling tolerance of watermelon scion. All Cucurbit germplasms showed higher resistance to FON1 than watermelon cultivar N5 (control). Watermelons grafted onto QZ1 showed the lowest wilt incidence and highest fruit yield but had the worst fruit quality after planting on soils continuously cropped for 11 years. Watermelons grafted onto TC showed higher resistance and yield and the best fruit quality. These findings indicate that TC has a large potential for use in grafting watermelon planted in continuously cropped soils (&lt; 10 years). TC can also be used as breeding rootstocks to improve watermelon resistance against continuous cropping obstacles without compromising fruit quality.

Differential sensitivity to thermal processing of two muskmelon cultivars with contrasting differences in aroma profile

The muskmelon aroma is delicate, but unacceptable off-notes can be formed during thermal processing, impeding the muskmelon industrial applicability. To investigate cultivar differences in the thermal sensitivity of their aroma, heat-induced aroma alterations of muskmelon cultivars with different aroma profiles and postharvest physiologies were comparatively studied using qualitative descriptive analysis, headspace-gas chromatography-ion mobility spectrometry, and a gas chromatography-olfactometry/modified frequency (MF) method. Higher intensities of “fermented” and “sulfurous” off-notes were observed in a non-climacteric Queen muskmelon (QM) compared to a climacteric Xizhoumi No. 25 muskmelon (XM). The number and MF values of odorants in QM and XM increased after heating. However, less agreeable odors and more off-flavors with higher MF values were identified in heated QM compared to XM. Both sensory and instrumental analysis revealed different thermal sensitivities between the muskmelon cultivars, which indicated that XM was better at retaining its original aroma and inhibiting the development of off-odors. This study provides theoretical guidance for muskmelon resource utilization and also promotes the muskmelon deep-processing products and growth in the muskmelon market.

Effect of Ripening Conditions on the Quality and Storability of Muskmelon (Cucumis melo L.) Fruits

This study was conducted to identify the effect of ripening conditions on quality of ‘Honey One’ and ‘Earl`s Talent’ muskmelon cultivars stored at 10°C with 80 ± 5% relative humidity (RH) and room temperature (RT; 25°C) with 50 ± 5% RH. Weight loss and respiration rate of both cultivars were lower at 10°C than at RT throughout the ripening period. In the case of ethylene and ethanol production, ‘Honey One’ showed higher production than ‘Earl`s Talent’. There was no significant difference in acetaldehyde production between the two cultivars. ‘Honey One’ had higher total soluble solids (TSS) than ‘Earl`s Talent’ throughout the ripening period. ‘Earl`s Talent’ showed lower sucrose but higher glucose and fructose contents than ‘Honey One’. Titratable acidity (TA) and firmness decreased in both cultivars during the ripening period. ‘Earl`s Talent’ maintained firmness longer than ‘Honey One’. The polygalacturonase (PG) activity of ‘Honey One’ decreased starting from the 6th day of ripening, reaching 12.58 nmol·kg-1·s-1 on day 9 and maintaining that level afterwards while at RT. By contrast, ‘Earl`s Talent’ maintained PG activity up to day 21. Both water soluble pectin (WSP) and ammonium soluble pectin (ASP) increased but hydrochloric acid soluble pectin (HSP) and sodium hydroxide soluble pectin (SSP) decreased as the ripening period proceeded. The Hunter`s L* value of the two cultivars showed a decreasing trend in the flesh regardless of the ripening temperature. The sensory evaluation scores for both cultivars were highest on day 15th at 10°C and on day 9th at RT. Overall, our results revealed that the best nutritional benefits of muskmelon were achieved on the 15th day of ripening at 10°C and on the 9th day of ripening at RT irrespective of cultivars.

Muskmelon Cultivar Attractiveness to Striped Cucumber Beetle and Susceptibility to Bacterial Wilt

Bacterial wilt of cucurbits, incited by Erwinia tracheiphila (E. F. Smith) and vectored by the striped cucumber beetle [Acalymma vittatum (F.)] (SCB), is a serious disease of muskmelon (Cucumis melo L.). Cultivars differ in attractiveness to SCB and susceptibility to bacterial wilt, but no cultivar resistant to bacterial wilt has been introduced. In 2015 and 2016, replicated field plots of eight cultivars were grown at Lafayette, Wanatah, and Vincennes, IN, to identify differences in attractiveness to SCB and susceptibility to bacterial wilt. ‘Savor’ had significantly more beetle activity than ‘Hales Best’, ‘Superstar’, and ‘Aphrodite’ in three of six site-years, and more than ‘Diplomat’, ‘Dream Dew’, ‘Athena’, and ‘Wrangler’ in two site-years. Beetle activity for ‘Athena’, ‘Superstar’, and ‘Wrangler’ did not differ significantly from ‘Aphrodite’ for any site-year. Bacterial wilt severity was significantly greater for ‘Diplomat’ and ‘Dream Dew’ than for other cultivars in four site-years. ‘Superstar’ had the least disease in five site-years, but significantly less than ‘Aphrodite’, ‘Athena’, and ‘Hales Best’ in only one site-year. At one site, additional plots of each cultivar were populated with five SCBs per plant, and rowcovers were applied to keep the SCBs near the plants for 3 weeks. This resulted in similar beetle activity on all cultivars, but most disease in ‘Dream Dew’ and least in ‘Superstar’ and ‘Athena’. Marketable yield was generally highest for ‘Aphrodite’, ‘Superstar’, and ‘Athena’ when plants were exposed to natural beetle populations. Overall, ‘Savor’ and ‘Diplomat’ were the most attractive to beetles, and ‘Diplomat’ and ‘Dream Dew’ were the most susceptible to bacterial wilt. ‘Aphrodite’, ‘Athena’, and ‘Superstar’ were less attractive to beetles and showed more tolerance to bacterial wilt in both 2015 and 2016.

Genetics Analysis and Heritability of Fruit Characters in Muskmelon (Cucumis melo L.) Using Extreme Parental Differences

Taeng-Thai is the Thai name for oriental pickling melon or muskmelon (Cucumis melo L.) which is a Cucumis species. Based on consumption as Thai traditional dessert, fruit characters at ripening stage are very important to improve the muskmelon cultivar. Understanding the genetic control of fruit traits is the key to a successful for crop improvement. Research aimed to determine the genetic effects, number of genes and heritability of fruit characters in muskmelon. The results have shown that both additive and dominant effects governed for fruit weight, fruit length, fruit width and fruit thickness with the number of gene as 40.26, 1.55, 10.70 and 11.10 genes, respectively. Simple phenotypic correlation coefficients shown, had a significant positive correlation among the four fruit traits. Due to the quantitative inheritance of fruit characters, quantitative traits loci (QTL) mapping of those traits were necessary to identify all controlling genes of fruit traits in further muskmelon improvement.

Somatic embryogenesis of muskmelon (Cucumis melo L.) and genetic stability assessment of regenerants using flow cytometry and ISSR markers.

A new protocol for in vitro regeneration through direct somatic embryogenesis for two muskmelon cultivars (Cucumis melo L., "Mashhadi" and "Eivanaki") is reported. Somatic embryos were obtained culturing 4- and 8-day-old cotyledons, seeds, and hypocotyls on Murashige and Skoog medium supplemented with three different hormonal combinations never tested so far for melon (naphthoxyacetic acid (NOA) + thidiazuron (TDZ), NOA + 6-banzylaminopurine (BAP), and 2,4-dichlorophenoxyacetic acid (2,4-D) + N-(2-chloro-4-pyridyl)-N'-phenylurea (4-CPPU)). Results were compared with those obtained when explants were cultivated in the presence of 2,4-D + BAP, previously used on melon. Embryogenesis occurred more successfully in 4-day-old cotyledons and seeds than hypocotyls and 8-day-old cotyledons. The best result was achieved with NOA + BAP. Genotypes significantly affected embryogenesis. The number of embryos in "Eivanaki" was significantly higher than that in "Mashhadi." Embryo proliferation when explants were maintained in jars (9.3%) was found to be higher compared to that in petri dishes. For the first time, genetic stability of regenerated melon plants was evaluated using inter-simple sequence repeat markers. Polymerase chain reaction (PCR) products demonstrated a total of 102 well-resolved bands, and regenerants were 93% similar compared to the mother plant. Somaclonal changes during embryogenesis were evaluated by flow cytometry, showing 91% of the same patterns in regenerated plants. The results suggest that the new hormone components are effective when applied for in vitro embryogenesis of muskmelon as they show a high frequency in regeneration and genetic homogeneity.

Investigation of different leaf characters on Muskmelon cultivars possessing grades of resistance to downy mildew disease

Investigation of different leaf characters on Muskmelon cultivars possessing grades of resistance to downy mildew disease

Development of a muskmelon cultivar with improved resistance to gummy stem blight and desired agronomic traits using gene pyramiding

Gummy stem blight (GSB), caused by Didymella bryoniae (Auersw.) Rehm., is a severe disease affecting Cucurbitaceae crops including melons. The resistance of current melon varieties that carry a single Gsb resistance gene is insufficient to protect against the abundant variation of the D. bryoniae isolates. Pyramiding multiple Gsb resistance genes into melon cultivars is an effective way to develop a broad resistance spectrum and to increase the duration of GSB resistance. In this study, two resistance genes (Gsb-4 and Gsb-6) from two resistant accessions, PI482398 and PI420145, were pyramided into one variety using marker-assisted selection (MAS). The donor parent 4598 that contained Gsb-4 and Gsb-6 was hybridized with muskmelon Baipicui to produce BC&lt;sub&gt;1&lt;/sub&gt;F&lt;sub&gt;1&lt;/sub&gt; and BC&lt;sub&gt;2&lt;/sub&gt;F&lt;sub&gt;1&lt;/sub&gt;. Phenotyping and MAS enabled identification and pyramiding of two Gsb genes in individuals of F&lt;sub&gt;1,&lt;/sub&gt; BC&lt;sub&gt;1&lt;/sub&gt;F&lt;sub&gt;1&lt;/sub&gt; and BC&lt;sub&gt;2&lt;/sub&gt;F&lt;sub&gt;1&lt;/sub&gt;. Field cultivation showed that individuals carrying both Gsb-4 and Gsb-6 had improved resistance to GSB and improved fruit quality. The results indicated that MAS-based pyramiding is an effective strategy for breeding melon cultivars with increased resistance to GSB.

Effects of Three Production Systems on Muskmelon Yield and Quality in New England

Muskmelons (Cucumis melo L.) are routinely grown on black plastic mulch, as the associated increase in soil temperatures, more stable soil moisture, and decreased weed competition result in higher yields than in bare soil production. However, mulch does little to moderate air temperature, which can be below optimum for melon production under New England conditions. One option for increasing air temperature is to grow plants in unheated hoophouses, or high tunnels. Another option is to use low tunnels consisting of ventilated clear plastic rowcovers supported over wire hoops. This study compared low tunnels and high tunnels to open field production for muskmelon production in a peri-urban market farm system in Rhode Island. Five hybrid muskmelon cultivars were grown for 2 years to compare earliness, yield, and fruit quality among the three production systems. Both tunnel systems increased the rate at which growing degree-days (GDD) accumulated relative to open field production, and resulted in statistically significant differences in starting date of first harvest, with fruit in the high tunnel treatment ripening first. The high tunnel production system increased yields per hectare in both years relative to the other production systems due to increased planting density, but not due to increased yields per plant. Marketable yields per hectare from the high tunnel system significantly exceeded those from the open field for four out of the five cultivars in 2011, but for only one out of five cultivars in 2012. Marketable yields from the low tunnel system were ≈10% higher than the open field in 2011, and almost double the open field yields in 2012. Fruit from the low tunnels had the highest concentration of soluble solids in both years. The high tunnel production system did not increase yields sufficiently to offset the associated increase in costs of production, suggesting that muskmelon is not a good crop for high tunnel production in New England. In contrast, a yield increase of only 15% would be sufficient to offset the increased costs of employing the low tunnel production system. Low tunnels have the potential to greatly benefit muskmelon production in New England, particularly in years or locations where GDD accumulate slowly.

Physiological analysis and transcriptome comparison of two muskmelon (Cucumis melo L.) cultivars in response to salt stress

Melon (Cucumis melo L.) is an important vegetable crop that ranks second in salt tolerance among the Cucurbitaceae. Previous studies on the two muskmelon cultivars 'Bing XueCui' (BXC) and 'Yu Lu' (YL) revealed that they had different characteristics under salt stress, but the molecular basis underlying their different physiological responses is unclear. Here, we combined a physiological study with a genome-wide transcriptome analysis to understand the molecular basis of genetic variation that responds to salt stress in the melon. BXC performed better under salt stress than YL in terms of biomass and photosynthetic characteristics, because it exhibited less reduction in transpiration rate, net photosynthesis rate, and stomatal conductance under 150-mM NaCl stress than YL. A transcriptome comparison of the leaves of the cultivars revealed that 1171 genes responded to salt stress in BXC while 1487 genes were identified as salt-stress-responsive in YL. A real-time polymerase chain reaction analysis of 12 of the responsive genes revealed that there was a strong, positive correlation with RNA sequencing data. The genes were involved in several pathways, including photosynthesis, the biosynthesis of secondary metabolites, metabolism, and plant hormone signal transduction, and their expression levels differed between the two cultivars in response to salt stress. This study provides a molecular perspective of two melon cultivars in response to salt stress, and its results could be used to investigate the complex molecular mechanisms underlying salt tolerance in the melon.

Effect of rootstock on muskmelon cultivar reaction to vine decline disease and yield under arid conditions

Monosporascus cannonballus, Rhizoctonia solani and Pythium aphanidermatum are the main causal agents of muskmelon vine decline disease in Oman. This study was conducted to examine the response of six cucurbit rootstocks grafted on four muskmelon scions to the causal agents and fruit quality and quantity. The response of 10 day old Palmira seedlings to artificial inoculation with R. solani pathogen alone revealed more damage to muskmelon seedling whereas P. aphanidermatum and M. cannonballus caused less damage when inoculated singly but more disease severity index when combined with R. solani. Artificial inoculation of different rootstocks produced significantly no damping-off and very low vine decline disease severity index on Mubyeongjangsoo, Titan, Tetsukabuto, Rsscih7458, Ezra and Strong Tosa rootstocks. All rootstocks produced high grafting success and low graft failure with the four selected muskmelon cultivars. Rootstocks enhanced early harvesting of grafted Tamara but had no effect on other scions. Fruit shape was almost not significantly affected by grafting except Samit grafted on Strong Tosa and Caramel grafted on Mubyeongjangsoo produced significantly different fruit shapes compared to ungrafted controls in the spring 2013 trial. Fruits from both grafted Shahd and Tamara showed no significant differences in rind brightness, redness and yellowness from the control. An various effect of rootstock was found on harvesting, fruit number and weight, chlorophyll content, and stem diameter of the scion. Rootstocks enhanced early harvesting and increased fruit number and fruit weight in grafted Tamara scions. There was no significant effect of grafting on fruit TSS. The study shows positive effects of grafting on tolerance to vine decline and on fruit quality and yield.

Pre- and postharvest attributes of muskmelon cultivars for fresh-cut cubes

The choice of the appropriate cultivar is a critical factor for obtaining a successful crop and for satisfying the needs of the industry and consumers. Nine commonly used or recently available varieties of cantaloupe melons ( Cucumis melo L. Group Cantalupensis) were evaluated in two locations with the objective of selecting cultivars ad hoc for processing as fresh-cut cubes. Overall, the yield (30 to 45 t ha-1) and quality, including mainly the fruit size and soluble solids concentration (SSC), varied between locations, but the relative performance of cultivars was similar. The cultivars showed significant differences in attributes that are relevant for the industry and the consumer: color (from yellow to deep orange), SSC (from 8.7 to 14.7%), firmness (11.2 to 32.8 N), and chilling injury after refrigerated storage for 18 days at 0 oC (from none to slight) and after 3 additional days at 20 oC (from none to severe). Cultivars such as Diva, Fiji, and Glamour presented attributes that make them especially valuable for the fresh-cut processing industry. La eleccion del cultivar apropiado es un factor critico para la obtencion de una produccion exitosa y para satisfacer las necesidades de la industria y los consumidores. Nueve cultivares de melon reticulado ( Cucumis melo L. Group Cantalupensis) de uso comun o reciente disponibilidad se evaluaron en dos localidades con el objetivo de seleccionar cultivares apropiados para la elaboracion de cubos minimamente procesados. En general, el rendimiento (30 a 45 t ha-1) y la calidad, principalmente el tamano del fruto y la concentracion de solidos solubles (CSS), vario entre localidades, sin embargo, el rendimiento relativo de los cultivares fue similar. Los cultivares mostraron diferencias significativas en los atributos relevantes para la industria y el consumidor: el color (de amarillo a naranja intenso), la CSS (de 8.7 a 14.7%), la firmeza (11.2 a 32.8 N) y el dano por enfriamiento despues de almacenamiento refrigerado durante 18 dias a 0 °C (de ninguno a leve) y despues de 3 dias adicionales a 20 oC (de ninguno a severo). Los cultivares como Diva, Fiji y Glamour presentaron atributos que los hacen especialmente valiosos para la industria de productos minimamente procesados.

Quantifying the Relationship between Leaf Nitrogen Content and Growth Dynamics and Yield of Muskmelon Grown in Plastic Greenhouse

The aim of this study was to quantitatively investigate the impacts of nitrogen on growth dynamics and yield, so as to facilitate the optimization of nitrogen management for muskmelon crop in plastic greenhouse. For this purpose, four experiments with different levels of nitrogen treatment and planting dates on muskmelon (Cucumis melo L. ‘Nanhaimi’ and ‘Xizhoumi 25’) were conducted in plastic greenhouse located at Sanya from Nov. 2012 to Sept. 2014. The quantitative relationship between leaf nitrogen content and growth dynamics and yield of muskmelon was determined and incorporated into a photosynthesis-driven crop growth model (SUCROS). Independent experimental data were used to validate the model. The critical leaf nitrogen content at flowering stage for muskmelon ‘Nanhaimi’ and ‘Xizhoumi 25’ were 19.8 and 21.0 mg·g−1. The coefficient of determination (r2) and the relative root-mean-squared error (rRMSE) between the predicted and measured value of growth dynamics and yield were, respectively, 0.91 and 10.8% for leaf area index (LAI), 0.90 and 19.6% for dry weight of shoot (DWSH), 0.76 and 30.3%, 0.82 and 21.1%, and 0.92 and 11.9% for dry weight of leaf (DWL), stem (DWST), and fruit (DWF), 0.91 and 17.3%, 0.89 and 13.9%, 0.86 and 27.8%, and 0.88 and 20.6% for soluble sugar content (SU), soluble protein content (PR), vitamin C content (VC), and soluble solids content (SO) of fruit, and 0.90 and 10.1% for fresh weight of fruit (FWF). The model could be used for the optimization of nitrogen management for muskmelon production in plastic greenhouse. Further calibration and test would be needed during the application of the model in wider range of conditions and muskmelon cultivars.