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Mudas de melancia produzidas com substrato à base de pó de coco e solu??es nutritivas
Ramos, Anamaria RP;Dias, Rita de Cássia S;Arag?o, Carlos Alberto;Mendes, Alessandra MS;
Horticultura Brasileira , 2012, DOI: 10.1590/S0102-05362012000200026
Abstract: the choice of substrate is one of the most important stages for the seedlings production and must take into account the nutritional requirements of cultivated species. thus, the objective was to evaluate the substrate using coconut dust associated with nutrient solutions to produce seedlings of watermelon. the experiment was carried out at embrapa semi-arid in petrolina, pernambuco state, brazil, in a greenhouse in a completely randomized design with ten replications in a factorial arrangement 2 x 10 (cultivars of watermelon and substrates). the cultivars used were: opara and top gun. the coconut fiber was associated with nutrient solutions as follows: t1= control treatment composed of the commercial organic substrate plantmax? (sc), t2= coconut powder (pc), t3= coconut powder + melon solution (pc+sm), t4= coconut powder + solution of hoagland and arnon 12.5% (12.5% pc+hs), t5= coconut powder + solution of hoagland and arnon 25% (pc+hs 25%), t6= coconut powder + solution of hoagland and arnon 50% (pc+hs 50%), t7= coconut powder + solution of hoagland and arnon 75% (pc+hs 75%), t8= coconut powder + solution of hoagland and arnon 100% (100% pc+hs), t9= coconut powder + aminoagro mol (pc+am), t10= coconut powder aminoagro root (pc+ar). the solutions were applied eight times, 10 ml on each application, since the fourth day after sowing date (das), when the evaluation of seedlings emergence began. at 24 das we evaluated the fresh weight of shoots and roots, root length, number of roots in the upper third and contents of macro and micronutrients in the aboveground part. the cv. top gun presented higher levels of nutrients, except for iron and copper. the treatments t6, t7 and t8 presented levels of nutrients in plants similar to the commercial substrate plantmax. in general, the combinations of coconut dust associated with the nutrient solution of hoagland and arnon at 50, 75 and 100% and aminoagro root proved to be promising for the formation of watermelon seedlings on t
Rea??o de genótipos de melancia ao crestamento gomoso do caule
Santos, Gil Rodrigues dos;Café Filho, Adalberto C.;
Horticultura Brasileira , 2005, DOI: 10.1590/S0102-05362005000400017
Abstract: gummy stem blight, caused by didymella bryoniae, is one of the most important watermelon diseases. nevertheless, there are relatively few published studies on the response of watermelon genotypes to the disease. this paper reports results of studies on the response of commercially available watermelon cultivars to gummy stem blight. leaf infection was studied in a randomized complete block field experiment with nine watermelon genotypes and four replicates. two plants per experimental plot were inoculated 43 days after planting. cultivars crimson sweet, onix, rubi, safira, eureka, georgia, sheila, savana and riviera were evaluated. stem infection was studied in the greenhouse, in a completely randomized design, with three replicates, in a 9 x 3 factorial, where plant cultivars corresponded to factor "a" and pathogen isolates corresponded to factor "b". the same nine cultivars were examined following artificial inoculation with mycelial disks inserted into stems, 15 days after planting date, when plants were at the first adult leaf stage. the d. bryoniae isolates were unb 76 (melon-df), unb 75 (watermelon-pe) and unb 81 (pumpkin-df). in the field experiment, riviera was the most resistant genotype, with significantly (p<0.05) lower values of leaf infection at 74 and 79 dap and the smallest area under disease progress curve (audpc). crimson sweet, rubi, onix and safira were the most susceptible genotypes based on foliar disease levels 74 days after planting and also based on the audpcs. in the greenhouse, riviera also presented the smallest (p<0.05) audpc in stems. a significant correlation (r=0.77) was detected between disease measurements in the greenhouse (stem response) and in the field (foliar response).
Progresso do crestamento gomoso e perdas na cultura da melancia
Santos, Gil R. dos;Café-Filho, Adalberto C.;Le?o, Fernando F.;César, Marcos;Fernandes, Luzia E.;
Horticultura Brasileira , 2005, DOI: 10.1590/S0102-05362005000200013
Abstract: progress and losses due to gummy stem blight were studied in field plots artificially inoculated with didymella bryoniae. for the temporal disease progress study, two fields (24 x 32 m) were established in areas free of the disease, without any history of cucurbit cultivation, and no control measures were applied. data for the disease progress curves were obtained from the mean diseased leaf area in an area of 768 m2, at 45; 50; 55; 60; 65; 74; 80 and 87 days after planting (dap). disease progressed according to the exponential model, even under marginally favorable environmental conditions. maximum severity values were observed 87 dap (12.5-13.6% diseased leaf area). the crop loss experiment was laid out in a randomized completed block design with five disease levels and four replicates. disease levels were obtained with the application of five fungicide doses (per 100 l of water) of a mixture of active ingredients chlorothalonil and methyl thiophanate, as follows: (a) 0 g a.i. (control); (b) chlorothalonil 25 g + methyl thiophanate 10 g; (c) chlorothalonil 75 g + methyl thiophanate 30 g; (d) chlorothalonil 125 g + methyl thiophanate 50 g; (e) chlorothalonil 250 g + methyl thiophanate 100 g. disease severity was evaluated once, 78 dap, with a disease scale ranging from 0 to 9, based on the percentage of diseased leaf area. maximum disease levels were observed 78 dap in control plots (26.5% diseased leaf area). there was high negative correlation (r=-0.96) between disease levels and fruit yield. yield losses due to gummy stem blight reached 19.2% and chemical control reduced disease levels significantly.
Adequa??o da metodologia do teste de tetrazólio para avalia??o da qualidade fisiológica de sementes de melancia
Bhering, Maria Carmen;Dias, Denise Cunha Fernadnes dos Santos;Barros, Daniella Inácio;
Revista Brasileira de Sementes , 2005, DOI: 10.1590/S0101-31222005000100022
Abstract: this study was conducted with the objective of adjusting the methodology of the tetrazolium test for physiological quality evaluation of watermelon seeds. in the first stage, the most appropriate tetrazolium test procedure was determined. the following procedures were evaluated: seed moistening in wet paper towel for 16 and 24 h and immersion in water at 40oc for 30, 40 and 60 minutes for tegument removal , and for 30, 40 and 60 minutes for removal of embryo surrounding membrane. then, the seeds were placed in 0.075% tetrazolium solution at 40oc, in the dark, for 30, 40 and 60 minutes. each sample tested by tetrazolium test was also evaluated for germination and seedling emergence tests establishing criteria for viability and vigor evaluation. in the second stage, the most appropriate tetrazolium methodology was applied to eight seed lots and the results were compared for germination, first count, accelerated aging and seedling emergence tests. five classes of viability were established: vigorous (classes 1 and 2), viable (classes 1 to 3) and non-viable and dead seeds (classes 4 and 5, respectively). the results indicated that the tetrazolium test was efficient for viability and vigor evaluation of watermelon seeds. the seeds should be immersed in water at 40oc for 40 minutes for removal of the tegument followed by 60 minutes for the removal of the endosperm membrane. the ideal staining was obtained after 60 minutes immersion in a 0.075% tetrazolium solution at 40oc.
Nutritive Values and Antioxidant Activity of Citrullus lanatus Fruit Extract  [PDF]
Adewale Adetutu, Olubukola Sinbad Olorunnisola, Olusoji Abiodun Owoade
Food and Nutrition Sciences (FNS) , 2015, DOI: 10.4236/fns.2015.611109
Abstract: Citrullus lanatus (Watermelon) is a fruit cultivated and consumed in Africa for its essential nutrients which are very beneficial to the human body. The present study was designed to evaluate the nutritive contents, free radical scavenging activities and phytochemical components of C. lanatus fruit. The extract of the fruit was subjected to in vitro antioxidant assessment using 1,1-di-phenylpicryl-hydrazyl radical (DPPH) and hydrogen peroxide radical scavenging assays. The proximate and phytochemical analyses were conducted using standard procedures. The results of this study showed that C. lanatus fruit had very high moisture content and its crude protein, crude fat, crude fibre and ash content were all in traceable amounts. The sugar content was considerably high in comparison with other nutritive contents. Lycopene and β-carotene contents of C. lanatus fruit were estimated to be 4537.83 and 308.71 μg/100g respectively. The gross energy evaluation showed a value of 0.335 Kcal/g. The fruit extract exhibited significant (p < 0.05) DPPH (IC50 of 0.10 mg/ml) and hydrogen peroxide radicals scavenging activity (IC50 of 0.62 mg/ml) in comparison with the positive control butylated hydroxytoluene (BTH). This study therefore recommends that C. lanatus fruit could be an excellent source of antioxidants which may prevent diseases whose pathogenesis involves oxidative stress.
Characterization of Water Melon (Citrullus lanatus) Genotypes under High Salinity Regime  [PDF]
Mujahid Ali, C. M. Ayyub, Muhammad Rashid Shaheen, Rashad Waseem Khan Qadri, Imran Khan, Muhammad Azam, Naheed Akhtar
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.619317
Abstract: For horticultural crops and especially for vegetables, salinity is dilemma. It is the most limiting factor for plant growth and development by producing reactive oxygen species and ultimately oxidative stress. In the present study, the screening of watermelon (Citrullus lanatus Thanb. Mavs.) Cultivars was observed for salt tolerance. Four salinity levels (1.5, 3, 4.5, and 6 dS·m-1 NaCl) and six cultivars (Crimson, Charleston Gray, Anarkali, Chairman, Sugar Baby and Champion) tested for screening. It was observed that all morphological attributes and ionic contents were severely affected. But it was revealed by statistical analysis that Charleston Gray was affected least while Champion was most salt sensitive cultivar due to oxidative stress and ionic toxicity. It is concluded that different genotypes under consideration vary in their ability to tolerate salt stress.
Avalia??o de genótipos de melancia para resistência ao Papaya ringspot vírus, estirpe melancia
Vieira, Jairo V;ávila, Antonio Carlos de;Silva, Giovani Olegário da;
Horticultura Brasileira , 2010, DOI: 10.1590/S0102-05362010000100002
Abstract: the aim of this study was to assess the resistance of nine watermelon genotypes against three prsv-w isolates originated from three brazilian states (s?o paulo, goiás and pernambuco). the experiment was carried out at embrapa hortali?as, brasilia, brazil, in april 2004. nine watermelon genotypes were appraised, in a randomizated block design with four replications. each plot was comprised of one 5 kg pot and five watermelon plants per pot. ten to 13 days after sowing, inoculation was carried out with three prsv-w isolates. twenty-seven and 37 days after sowing, virus symptoms were evaluated. virus presence or absence in the inoculated plants was confirmed by das-elisa. the results comprised variance analysis, heritability estimation, correlations among the characters, and genotype comparisons. based on the different behavior of the genotypes in relation to each prsv-w isolate, it is concluded that different isolates should be used in watermelon breeding programs. the high heritability values for most of the characters indicated that the characteristic in study is under the control of a few loci and, therefore, the possibility of selection of resistant watermelon accesses is high. the evaluated genotypes showed higher virus tolerance compared to the most planted cultivar in the country (crimson sweet), as it can be verified by the average values. the results suggest that the selected watermelon accesses are a good source of resistance to new watermelon cultivars tolerant to prsv-w.
Controle químico do crestamento gomoso do caule em melancia
Santos, Gil R.;Café-Filho, Adalberto C.;Saboya, Luciano M. F.;
Fitopatologia Brasileira , 2005, DOI: 10.1590/S0100-41582005000200009
Abstract: this work reports the results of the effects of chemical control and nitrogen-potassium fertilization on gummy stem blight, one of the most important watermelon (citrullus lanatus) diseases. two factorial field assays were conducted in projeto formoso, tocantins, in a randomized block design with four replicates. experimental plots measured 30 x 10 m. treatments for assay i were (factor a - active ingredients/100 l water or ha): (1) mancozeb (manc)-160.2 ml, (2) methyl thiophanate (tm)-49 g, (3) carbendazin-500 ml, (4) tebuconazole-20 g, (5) difenoconazole (dife)-75 ml, (6) methyl thiophanate-40 g + chlorothalonil -100 g, (7) copper oxychlorate-168 g, (8) trifloxistrobina-87.5 g + propiconazole-87.5 g, (9) mancozeb-80 ml + difenoconazole-37.2 ml, and (10) control. treatments for factor b were two levels of n-k fertilization: (1) 30-20, and (2) 90-60 kg/ha. disease severity on leaves was evaluated on a 0 to 9 scale. for the assay ii, treatments for factor a were repeated, while treatments for factor b were n-k fertilization levels (kg/ha) 60-40 and 120-80. on both assays, lowest areas under disease progress curves (audpd), were obtained with manc + dife, tm + chlorothalonil, manc, trifloxistrobina + propiconazole and copper oxychlorate. fertilization did not affect disease severity. larger yields were obtained with tm + chlorothalonil, manc + dife and manc.
Problemas na premuniza??o de melancia para o controle do mosaico causado pelo Papaya ringspot virus
Fitopatologia Brasileira , 2001, DOI: 10.1590/S0100-41582001000300013
Abstract: studies were carried out to evaluate the protective effect of two mild strains of papaya ringspot virus, watermelon strain, on watermelon (citrullus lanatus) plants under greenhouse and field conditions. the results showed that protection was positive under both conditions. however, protected plants of 'crimson sweet' showed a reduction on the average weight of fruit per plant of, approximately, 50% and 10.8%, as compared to the yield of healthy plants, in the first and second trials, respectively. yield reduction on protected 'crimson tide' was approximately 36.4% in one trial. in addition to yield reduction, another problem associated with cross protection in watermelon was the requirement of two successive inoculations of the seedling, on consecutive days, to increase the frequency of protected plants.
Evapotranspiration and crop coefficient of drip irrigated watermelon in Piaui coastline, Brazil
Bastos, Edson A.;Silva, Cláudio R.;Rodrigues, Braz H. N.;Andrade Jr., Aderson S.;Ibiapina, Lívia M. M.;
Engenharia Agrícola , 2012, DOI: 10.1590/S0100-69162012000300017
Abstract: the knowledge of the evapotranspiration (etc) and crop coefficient (kc) is fundamental to plan and to manage the irrigation of any crop. the aim of this study was to determine the daily and hourly evapotranspiration of drip irrigated watermelon (citrullus lanatus, var. crimson sweet) and crop coefficient (kc) in each crop development phase. the experiment was carried out in an experimental area of 1.27 ha of embrapa mid-north, localized in parnaíba (02°54's, 41°47'w and 46 m above of sea), state of piauí, brazil, from september to november, 2006. electronic weighing lysimeters of 1.5 m x 1.5 m wide and long and 1.0 m deep were used to obtain the evapotranspiration. the plants were drip irrigated with a lateral row per plant row and drippers spaced 0.5 m from each other. the reference evapotranspiration (eto) was estimated using the penman-monteith equation from the climatic data obtained by electronic sensors. the total evapotranspiration during the watermelon crop cycle cultivated in the state of piauí was 233.87 mm, with mean values of 3.7 mm day-1, minimum of 1.18 and maximum of 8.14 mm day-1. the kc of the drip irrigated watermelon was 0.18 in the initial stage of crop growth; 0.18 to 1.3, in crop development stage; 1.3 in the intermediate stage and 0.43 in the final stage.
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