| Journal: | Horticultura brasileira |
| Database: | PERIÓDICA |
| System number: | 000296303 |
| ISSN: | 0102-0536 |
| Authors: | Santos, Gil Rodrigues dos1 Cafe-Filho, Adalberto C2 |
| Institutions: | 1Universidade do Tocantins, Gurupi, Tocantins. Brasil 2Universidade de Brasilia, Departamento de Fitopatologia, Brasilia, Distrito Federal. Brasil |
| Year: | 2005 |
| Season: | Oct-Dic |
| Volumen: | 23 |
| Number: | 4 |
| Pages: | 945-950 |
| Country: | Brasil |
| Language: | Portugués |
| Document type: | Artículo |
| Approach: | Experimental |
| English 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) |
| Portuguese abstract | Face à importância do crestamento gomoso do caule e à escassez de relatos da reação de genótipos de melancia na literatura nacional e internacional, este trabalho teve por objetivo avaliar a resposta de genótipos comerciais de melancia ao crestamento gomoso. No campo, estudou-se o nível de infecção nas folhas em delineamento de blocos ao acaso com nove cultivares de melancia e quatro repetições, com inoculação de duas plantas por parcela aos 43 dias após o plantio (DAP). Foram avaliadas as cultivares Crimson Sweet, Onix, Rubi, Safira, Eureka, Georgia, Sheila, Savana e Riviera. Em casa de vegetação, estudou-se a infecção no caule em vasos, com delineamento inteiramente casualizado, com três repetições, em esquema fatorial de 9 x 3, sendo o fator "a" = cultivares e o fator "b" = isolados. Foram avaliadas as mesmas cultivares do ensaio de campo, com inoculação artificial com disco de micélio aos 15 dias após a semeadura, quando do surgimento da primeira folha definitiva. Os isolados de D. bryoniae utilizados na inoculação das plântulas foram: UnB 76 (Melão-DF), UnB 75 (Melancia-PE) e UnB 81 (Abóbora-DF). Dentre as cultivares avaliadas no campo, Riviera mostrou-se mais resistente e apresentou menores (P<0,05) índices de infecção foliar aos 74 e 79 dias após plantio (DAP), e também menor valor da área abaixo da curva de progresso de doença (AACPD). Foram altamente suscetíveis Crimson Sweet, Rubi, Onix e Safira, que apresentaram os mais altos níveis de infecção nas folhas aos 74 DAP e também altos valores de AACPD |
| Disciplines: | Agrociencias |
| Keyword: | Fitopatología, Frutales, Sandía, Citrullus lanatus, Didymella bryoniae, Variedades, Resistencia a plagas |
| Keyword: | Agricultural sciences, Fruit trees, Phytopathology, Watermelon, Citrullus lanatus, Didymella bryoniae, Cultivars, Pests resistance |
| Full text: | Texto completo (Ver HTML) |
