ABSTRACT
Avaliou-se o efeito de doses de nitrogênio, aplicadas em campo, sobre as doenças pós-colheita nos cultivares de morango Camino Real, Festival e Oso Grande. O nitrogênio, tendo como fonte a ureia, foi avaliado na dose recomendada total (100%), com base na recomendação oficial para a cultura, e mais 3 doses inferiores (83, 67 e 50% do recomendado), tanto no plantio como em cobertura. Os frutos foram colhidos e pesados com 75% da superfície de cor vermelho-brilhante. Doze frutos por parcela foram amostrados em 3 coletas a partir da segunda florada e avaliados quanto à incidência das doenças durante 5 dias de armazenamento a 25°C e 85% de umidade relativa. A identificação das doenças foi feita diariamente com base nos sintomas e sinais dos patógenos. Não foi observado efeito das doses de nitrogênio na produção de frutos e na incidência das doenças, expressa em área abaixo da curva de progresso da doença (AACPD). A maior produção foi observada nos cultivares Festival e Oso Grande. A incidência total de doenças não diferiu significativamente entre os cultivares. O mofo cinzento foi a principal doença, com incidência superior a 30%, seguido da podridão mole de Rhizopus e podridão de levedura.(AU)
This study evaluated the effect of nitrogen doses on postharvest diseases of strawberry cultivars Camino Real, Festival and Oso Grande. The nitrogen in urea formulation was evaluated at the recommended dose (100%) based on the official recommendation to the culture, and 3 lower doses (83, 67 and 50% of recommended), considering the fertilization at planting and cover applications. Fruits were harvested and weighed at 75% of its surface with a bright red color. Twelve fruits per plot were sampled in 3 collections from the second flowering and assessed for disease incidence during five days of storage at 25°C and 85% relative humidity. The identification of disease was made daily, based on symptoms and pathogen signs. There was no effect of nitrogen doses on yield and incidence of postharvest diseases, expressed as area under the disease progress curve (AUDPC). Increased average production was observed in cultivars Festival and Oso Grand. The overall incidence of disease among the cultivars did not differ significantly. Gray mold was the main disease, affecting more than 30% of fruits, followed by Rhizopus and yeast rot.(AU)
Subject(s)
Botrytis , Fragaria , Fungi , Mucor , Nitrogen , Plant DiseasesABSTRACT
Aims: To study storage rots in yam varieties cultivated in South East Nigeria and to determine under conditions of experimental storage, the influence of fungal rot on their post harvest storage losses. Place and Duration of Study: Laboratories, Department of Applied Microbiology & Brewing, Nnamdi Azikiwe University, Awka, Nigeria between January 2012 and July 2013. Methodology: Five yam varieties; Dioscorea dumentorum, two varieties each of D. alata and D. rotundata, obtained immediately after harvest were stored in an experimental barn (30ºC and 95% RH) and examined at intervals for storage rots. Fungal causative agents of rots were isolated and identified using the partial ITS rDNA sequencing analysis and a BLAST search using the GenBank sequence database. Post harvest storage losses in terms of weight loss and reduction of shelf life among the varieties were determined. Results: All varieties of yams studied suffered fungal rots, predominantly, dry rots during storage. Seven distinct fungal isolates, which caused these rots, were fully characterized. The species were Aspergillus tamari, Fusarium solani, Lasiodiplodia theobromae, Aspergillus niger, Mucor circinelloides, Aspergillus flavus and Aspergillus sp. In all the yams, storage rots reduced shelf life and aggravated weight loss. Post harvest storage losses varied among the different varieties of yams. Conclusion: The varieties of yams studied suffer rots from various fungi, which are similar to those reported in other parts of the world. Severity of post harvest losses resulting from fungal rots varies among different varieties of yams. This should be taken into consideration in the development of storage techniques.
Subject(s)
Databases, Nucleic Acid , Dioscorea/classification , Dioscorea/metabolism , Dioscorea/microbiology , Food Contamination/prevention & control , Food Microbiology , Food Preservation/methods , Food Storage , Fungi , Nigeria , Plant Diseases/etiology , Sequence Analysis, DNAABSTRACT
No Brasil, diversas espécies de Fusarium são patogênicas ao milho, afetando sementes, plântulas, colmos e grãos. Objetivou-se comparar isolados de F. verticillioides e de duas espécies do complexo F. graminearum (F. graminearum sensu stricto e F. meridionale), de ocorrência predominante em sementes de milho, quanto à taxa de crescimento micelial, capacidade de colonização e redução da germinação da semente, redução da emergência de plântulas e infecção e colonização de colmos de milho.Testes permutacionais e análise de contraste foram usados para discriminar os isolados. Análise de componentes principais foi utilizada para identificar as variáveis responsáveis pela maior variância entre os isolados. Com exceção da redução da germinação, os isolados F. verticillioides apresentaram menores valores de taxa de crescimento micelial, eficiência de infecção, redução na emergência de plântulas e comprimento de lesão em colmos, quando comparados aos demais, que não se diferenciaram. As variáveis redução da emergência e redução da germinação apresentaram maior influência na caracterização dos isolados, sugerindo que sementes infectadas com isolados de qualquer uma das espécies do complexo F. graminearum testadas representam maior risco ao estabelecimento da cultura do que isolados de F. verticillioides.
In Brazil, several Fusarium species are pathogenic to corn affecting seeds, seedlings, stalks and grains. This research aimed to compare isolates from F. verticillioides and from two species of the F. graminearum complex (F. graminearum sensu stricto and F. meridionale) prevalent on corn seeds in relation to mycelial growth rate, ability to colonize and reduce seed germination, reduction in seedling emergence and infection and colonization of corn stalk. Permutational test and contrast analysis was performed to discriminate the isolates and species. Principal component analysis was used to identify the variables leading to greatest variance among the isolates. With the exception of seed germination, F. verticillioides isolates showed lower values for mycelial growth rate, infection efficiency, reduction in seedling emergence and lesion size than F. graminearum complex isolates that were all similar. Seedling emergence and seed germination showed greater influence on the characterization of isolates, suggesting that seeds infected with F. graminearum isolates of any of the species tested represent a greater threat to crop stand than F. verticillioides isolates.
ABSTRACT
En este trabajo se evaluó el efecto antifúngico del quitosano (0; 0,5; 1,0; 1,5; 2,0 mg mL-1) en el desarrollo in vitro (crecimiento micelial, formación de cuerpos fructíferos, esporulación, germinación y liberación de proteínas) de Rhizopus stolonifer en dos medios de cultivo (papa dextrosa agar y medio mínimo). Los resultados obtenidos demostraron que el quitosano inhibió el crecimiento micelial de R. stolonifer en ambos medios de cultivo. El mayor índice antifúngico se observó en el medio papa dextrosa agar. El quitosano no afectó la formación de los cuerpos fructíferos de R. stolonifer en los medios estudiados. La esporulación y la germinación de las esporas se afectaron en ambos medios de cultivo por efecto de quitosano, siendo más notable en el medio medio mínimo. Se demostró la liberación de proteínas por efecto del quitosano en medio mínimo y caldo papa dextrosa. En general, en este estudio se evidenció el efecto antifúngico del quitosano en el desarrollo in vitro de Rhizopus stolonifer con independencia del medio de cultivo empleado. Sin embargo, en medio medio mínimo podrían observarse mejor los efectos antifúngicos del quitosano.
In this work the antifungal effect of chitosan (0, 0.5, 1.0, 1.5, 2.0 mg mL-1) on the in vitro development (mycelial growth, fruit bodies formation, sporulation, germination and proteins release) of Rhizopus stolonifer on two culture medium (Potato Dextrose Agar and Minimal medium) was evaluated. The obtained results demonstrated that chitosan inhibited the mycelial growth of R. stolonifer in both culture medium. The highest antifungal effect was observed on potato dextrose agar medium. Chitosan was not affected the fruit bodies formation of R. stolonifer on the studied medium. Sporulation and spore germination were affected in both culture mediun by effect of chitosan, it was more noticeable in minimal medium. It was demonstrated proteins release by effect of chitosan in minimal medium and potato dextrose broth medium. In general, in this study it was showed the antifungal effect of chitosan on in vitro development of Rhizopus stolonifer regardless of the culture medium used. However, in minimal medium could be observed best the antifungal effects of chitosan.
Subject(s)
Chitosan , Chitosan/radiation effects , Chitosan/chemistry , Chitosan/chemical synthesisABSTRACT
Neste trabalho, objetivou-se testar o efeito de tratamento com fungicidas e sua combinação com hidrotérmico, na conservação e qualidade pós-colheita de mangas 'Palmer' (Mangifera indica L.) armazenadas sob condição ambiente por 12 dias. Os frutos foram colhidos no estádio de maturação fisiológica (coloração da casca vermelha arroxeada) e, imediatamente, transportados para o laboratório, onde foram padronizados quanto à coloração e ausência de injúrias e, em seguida, submetidos ao tratamento hidrotérmico (53° C/10 minutos), com os fungicidas, cloreto de dodecil dimetil amônio 12 por cento a 120 ppm ou imazalil 50 por cento a 1000 ppm, e associações destes tratamentos. Após secagem, as mangas foram armazenadas sob condição de ambiente (23±2° C, 65±5 por cento UR) por 12 dias e analisadas quanto à ocorrência de podridões, aparência, coloração da casca e da polpa, perda de massa, firmeza, taxa respiratória, e teores de sólidos solúveis, acidez titulável e ácido ascórbico da polpa. O experimento foi conduzido em delineamento inteiramente casualizado, disposto em esquema fatorial com 5 x 5, com 4 repetições e unidade experimental composta de 9 frutos. Nos frutos, de todos os tratamentos, não se observou sinais de murchamento até o sexto dia de armazenamento. A associação do tratamento hidrotérmico com fungicidas não se mostrou eficiente no controle de podridões e não afetou o amadurecimento de mangas 'Palmer', que apresentaram vida útil de 10 dias a 23° C, limitada pela aparência.
The objective of this work was to test of effect of treatment with fungicides and its combination with hydrothermal on the conservation and pos-harvest quality of 'Palmer' mangoes (Mangifera indica L.) stored at atmosphere conditions for 12 days. The fruits had been harvested in the stages of physiological maturation (purple-red rind), transferred to the laboratory where they were separated by color and absence of injuries and then underwent hydrothermal (53° C for 10') and/or chemical treatment with the fungicides dodecil dimethyl ammonium chloride at 120 ppm (12 percent) and imazalil at 1000 ppm (50 percent). After drying, fruits were stored at room temperature (23±2° C, 63±5 percent RH) for 12 days and analyzed every three days for rots, appearance, coloration of the rind and the pulp, weight and firmness loss, respiratory rate, and levels of soluble solids, titable acidity and ascorbic acid in the pulp. The experiment was arranged in completely randomized design, in a 5 x 5 factorial scheme, with 4 replicates. Experimental units comprised nine fruits. No withering signs were observed in any of the treatments until the sixth day of storage. The combination of hydrothermal and fungicide treatments were not efficient in controlling rots. A shelf life of ten days was observed in 'Palmer' mangoes stored at 23° C, which was limited by fruit appearance.