Ramularia leaf spot and boll rot are affected differently by organic and inorganic nitrogen fertilization in cotton plants

Interaction among nitrogen fertilization using bovine manure, poultry manure, Jatropha curcas seed cake and urea, and the diseases Ramularia leaf spot (RLS) and Boll rot (BR), caused by Ramulariopsis pseudoglycines and Diplodia gossypina, respectively, in cotton plants (Gossypium hirsutum L.), was studied under field conditions. Intensity (incidence and severity in percentage) of RLS and incidence (%) of BR were evaluated over time, starting in reproductive stage B1 (first visible flower bud). A randomized complete block design with a 4x4 factorial arrangement was used (fertilizers x doses), totaling 16 treatments with four replications. Disease progress was analyzed with the nonlinear Logistic and Gompertz models, obtaining the epidemiological parameters amount of initial disease (Y0) and progress rate (r). Plants fertilized with 50 kg N ha-1, presented an incidence twice greater than those obtained with other fertilizers. The Logistic model better fits RLS, but no model could represent BR. Only the epidemiological parameters of RLS were affected differently in this experiment compared to BR disease. The possible role of organic and inorganic nitrogen fertilization in the RLS and BR management is discussed.

Intensidade de doenças e produtividade de genótipos promissores de feijão em Quevedo, Equador / Intensity of diseases and productivity of genotypes promising bean in Quevedo, Ecuador

O objetivo desse trabalho foi quantificar a intensidade de doenças, o rendimento de grãos e seus componentes em genótipos promissores de feijão durante a safra agrícola de verão em Quevedo, Equador. Os materiais genéticos utilizados foram as linhas Cf4 0-0-2-1, Cf6 0-0-4-9 e Cf6-0-0-4-8 (hábito de crescimento determinado tipo Ia), SER-03 e SER-08 (hábito de crescimento indeterminado tipo IIb), e duas variedades estrangeiras FTS Soberano e BRS Valente (hábito de crescimento indeterminado, grupo preto) utilizadas como testemunhas. Foi quantificada a intensidade da ferrugem (Uromyces appendiculatus Pers.:Pers.) durante quatro semanas (09/09, 16/09, 23/09 e 30/09) e mela [Rhizoctonia solani (Kuhn)] durante seis semanas (26/08, 02/09, 09/09, 16/09, 23/09 e 30/09) em folíolos centrais destacados, sendo esses valores obtidos integralizados na área abaixo da curva de progresso da doença (AACPD). Para o caso da mela, foi quantificado também o número de lesões folíolo-1 durante os estádios reprodutivos R7 e R8. Após a colheita foi avaliada a incidência das podridões cinzenta [Macrophomina phaseolina (Tassi) Goid.] e parda (R. solani), e quantificados os componentes de produção por planta (número de nós, número de vagens, número de grãos, número de grãos por vagem e número de vagens estéreis) e rendimento (kg ha-1). O delineamento experimental foi o de blocos completos ao acaso com 7 tratamentos e 4 repetições. Para a comparação entre as médias dos tratamentos empregou-se o teste de Scott-Knott a 5% de probabilidade do erro. Destacou-se a variedade FTS Soberano por acumular uma menor AACPS da ferrugem. Com relação a mela, as linhas promissoras SER-03 e SER-08, e as variedades FTS Soberano e BRS Valente mostraram menor quantidade de doença em todas as variáveis analisadas. Para as doenças radiculares, as linhas Cf6 0-0-4-8 e SER-03 obtiveram menor incidência de podridão parda, entretanto esses mesmos materiais incluindo o SER- 08 evidenciaram superioridade sanitária para podridão cinzenta. A linha promissora SER-03 e as variedades FTS Soberano e BRS Valente mostraram médias superiores no número de nós por planta, número de vagens por planta, número de grãos por planta e número de grãos por vagem por planta. Finalmente, as linhas SER-08, Cf6 0-0-4-9 e SER-08 e a variedade BRS Valente obtiveram o maior rendimento de grãos (kg ha-1).

The objective of this study was to quantify the intensity of disease, yield and its components in bean genotypes promising during the summer season in Quevedo, Ecuador. The genetic material used were the lines Cf4 0-0-2-1, Cf6 0-0-4-9 and Cf6 0-0-4-8 (habit growth determinate type Ia), SER-03 and SER-08 (growth habit indeterminate type IIb), and two foreign varieties FTS Soberano and BRS Valente (black group with habit growth indeterminate) used as controls. The intensity of rust (Uromyces appendiculatus Pers.: Pers.) and web blight [Rhizoctonia solani (Kuhn)] were quantified in central leaflets during four weeks (09/09, 16/09, 23/09 and 30/09) for the first disease and six weeks (26/08, 02/09, 09/09, 16/09, 23/09 and 30/09) for the second, these values being paid-in the area under the disease progress curve (AUDPC). For the case of web blight was also quantified the number of lesions leaflet-1 during reproductive stages R7 and R8. Similarly, after the harvest was determined the incidence of gray rot [Macrophomina phaseolina (Tassi) Goid.] and brown (R. solani), and quantified the yield components per plant (number of nodes, number of pods, number of grains, number of grains per pod and sterile pods) and yield (kg ha-1). The experimental design was a randomized complete block design with seven treatments and four replications. To compare the treatment means was employed the test Scott-Knott at 5% probability of error. Highlighted the variety FTS Soberano for accumulate a lower AUDPCS rust. Regarding the web blight, the promising lines SER-03 and SER-08, and the varieties FTS Soberano and BRS Valente showed less disease in all variables. For root diseases, the lines Cf6 0-0-4-8 and SER-03 had a lower incidence of brown rot, however these same materials including the SER-08 showed superiority sanitary of gray rot. The promising line SER-03 and the varieties FTS Soberano and BRS Valente showed higher average number of nodes per plant, number of pods per plant, number of grains per plant and number of grains per pod per plant. Finally, the lines SER-08, Cf6 0-0-4-9 and the varieties SER-08 and BRS Valente showed a highest grain yield (kg ha-1).

Agronomía, producción y calidad de grano de variedades de soya durante dos épocas de cultivo / Agronomy, production and grain quality of soybean cultivars under two sowing times

El objetivo del estudio fue evaluar las características agronómicas, productivas y calidad de grano de las variedades de soya P-34 y KAMERUN introducidas de Colombia, en comparación con tres variedades nacionales, durante las épocas lluviosa y seca, en Quevedo, Los Ríos, Ecuador. Fueron evaluadas variables agronómicas (días a floración, acame de plantas, altura de planta y de carga), productivas (número de ramas por planta, de nudos por planta, de vainas por planta, de granos por vaina, de granos por planta y de semillas en 100 gramos, peso de 100 granos y de grano por parcela, así como rendimiento de grano por hectárea) y calidad de grano (rajadura en el tegumento, moteado, mancha púrpura e incidencia fúngica). El diseño experimental utilizado en este trabajo fue el de Bloques Completos al Azar (DBCA), con cinco tratamientos y cuatro repeticiones. Todas las variables fueron sometidas al análisis de variancia. Se empleó la prueba de Tukey (p>0,05) entre las medias de los tratamientos para cada época de forma independiente, mientras que para las medias obtenidas entre las épocas lluviosa y seca, se empleó la prueba t-Student. Según las condiciones en que se condujo este experimento, se constató la influencia de la época de siembra en la mayoría de variables evaluadas, mientras que el material genético promisorio, fue la variedad P-34, por mostrar características agronómicas, productivas y calidad de grano superiores a las demás, pudiendo ser recomendada para la siembra.

This work aimed to evaluate the agronomic, production and grain quality of soybean varieties KAMERUN and P-34 introduced from Colombia, compared with three national varieties during the rainy and dry season, in Quevedo, Los Ríos, Ecuador. Agronomic variables were evaluated (days to flowering, plants overturned, height plant and first pod), productive (number of branches per plant, nodes per plant, pods per plant, seeds per pod, grains per plant and seeds in 100 grams, weight of 100 seeds, grain per plot and grain yield per hectare) and grain quality (broken seed in the integument, seed mottling, purple stain and fungal incidence). The experimental design used in this study was the Complete Randomized Bloc design with five treatments and four replications. All variables were subjected to analysis of variance. Multiple range Turkey's test (p<0,05) was used, between treatment means for each season independently; while for the means obtained between the rainy and dry seasons, t-Student test was used. Under our conditions, most of the evaluated variables were affected by the planting season. The variety P-34 was considered a promising material for showing agronomic characteristics, grain production and quality superior to others and may be recommended for planting.