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Adaptacao de 6 variedades de gossypium hirsutum l. A o regadio do caia. Analises do crecimiento, producao e qualidade da fibra
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Resumo(s)
Con el presente trabajo se pretende contribuir para el estudio del crecimiento, producción y calidad de
la fibra de Gossypium hirsutum L., cultivado en condiciones ecológicas en el perímetro de riego del
Caia (Alentejo, Portugal). Con este objetivo instalamos un ensayo con 6 variedades ('Carmen', 'Celia',
'Crema', 'Flora', 'Lacta' e 'Sonia'), de ciclo medio-curto a medio-longo, sembradas en 3 fechas de
siembra (19/04, 30/04 y 16/05 en 2002, 20/03, 3/04 y 17/04 en 2003), en la Finca de Comenda (38º
54’ N, 7º 03’ W). Se han verificado diferencias entre las variedades en el porcentaje de germinación y
en los testes frío (18ºC, 7 días) y standard (30ºC, 4 días), registrando las semillas de ‘Celia’ y ‘Sonia’
mayores índices de vigor. La tasa de crecimiento relativa presentó una marcada tendencia
decreciente, justo desde los primeros estadios de desarrollo de las plantas, mientras que la tasa neta
de asimilación presentó una tendencia creciente hasta finales de Julio, decreciendo después
continuamente hasta el final del ciclo, con lo incremento del índice de área foliar (LAI) y la reducción
de la temperatura y del número de horas de luz. No se han observado diferencias entre las
variedades o fechas de siembra en los periodos del año en que se registraron los valores máximos de
LAI y del índice de crecimiento del cultivo (CGR), observándose LAI máximo con un desfase de 10 a
31 días relativamente a CGR máximo. El nudo de inserción de la primera rama fructífera (NFFB)
inferior se encontró en la variedad ‘Celia’ y en la fecha de siembra más precoz. El cutout (NAWF = 5)
se verificó entre el 20 de Julio (‘Celia’ en la siembra precoz) y 19 de Agosto (‘Flora’ en la siembra
tardía), reduciéndose con el retraso de la fecha de siembra, en todas las variedades, el número de
días después siembra (DAS) hasta el cutout. Los daños provocados por Earias sp. y
Heliothis/Helicoverpa, plagas que determinaron una elevada pérdida precoz de formas fructíferas,
resultaron en números de DAS hasta NAWF= 5 relativamente elevados, característicos de plantas sin
una carga fructífera suficiente para transferir los asimilados disponibles del crecimiento vegetativo.
Esta circunstancia, asociada a condiciones térmicas poco favorables al crecimiento y maduración de
las cápsulas formadas más tarde, resultaran en reducidos índices de cosecha y bajas retenciones,
principalmente en las primeras posiciones de fructificación y en los simpódios localizados más en bajo
en la canópia. Se han observado diferencias significativas en la producción de algodón bruto entre
variedades, con la variedad 'Celia', aquella que también evidenció más caracteres de precocidad, a
atingir producciones más elevadas. Lo retraso de la fecha de siembra, aunque permita mejores
condiciones para la emergencia y crecimiento inicial de las plantas, reduce la estación de crecimiento
disponible, tiendo al final un efecto negativo en la producción de algodón-bruto. Así, la producción de
algodón en la región del Caia exige la utilización de variedades de ciclo corto y fechas de siembra
precoces, sendo decisivo conseguir una elevada retención de cápsulas en las primeras posiciones y
ramas simpodiales para que lo periodo de crecimiento y maduración de las cápsulas aún coincida con
condiciones ambientales favorables. No se verificaran diferencias significativas, entre variedades y
fechas de siembra, en la clasificación de grado de color de las fibras producidas, aunque se tengan
observado diferencias en algunos de los índices de calidad comercial y tecnológica. En la actual
moldura de precios e ayudas de la Unión Europea, las productividades más elevadas se sitúan muy
cerca del umbral de rentabilidad del cultivo.
With this work we pretend to contribute for the study of the growth, production and fibre quality of Gossypium hirsutum L. grown in ecological conditions of the Caia Irrigated Perimeter (Alentejo, Portugal). With this goal, two field trials were established at Herdade da Comenda (38º 54’ N, 7º 03’ W), in 2002 and 2003, using 6 varieties ('Carmen', 'Celia', 'Crema', 'Flora', 'Lacta' e 'Sonia'), of medium-short to medium-full season, sown at 3 planting dates (19/04, 30/04 and 16/05 in 2002, 20/03, 3/04 and 17/04 in 2003). We have found significant differences between genotype germination percentage with the cool (18ºC, 7 days) and the warm test (30ºC, 4 days), with 'Celia' and 'Sonia' showing the major vigor indices. Relative growth rate shows a decreasing tendency thereafter the first development stages, although net assimilation rate shows a tendency to increase until the end of July, decreasing thereafter continuously until the end of the season, with the leaf area index (LAI) increase and temperature and sunlight periods reduction. We don't observe any inter genotype or planting date differences between the day of the year of peaks LAI or crop growth rate (CGR), being maximal LAI reached 10 to 30 days latter then peak CGR. 'Celia' and the early planting date reached the lower node of first fruiting branch NFFB. Cutout (NAWF = 5) occurred between 20 July ('Celia' at the early planting date) and 19 August ('Flora' at the latter planting date), decreasing the number of days after sowing (DAS) to reach cutout with the delay of the planting date in all genotypes. The damages caused by Earias sp. and Heliothis/Helicoverpa, plagues that have resulted in high loose of fruiting forms, resulted in a high number of DAS to reach NAWF = 5, characteristic of plants with a insufficient boll load to determine assimilate diversion of vegetative growth. This circumstance, reinforced by inadequate temperatures to growth and maturation of bolls later set in season, resulted in poor harvest indexes and low retention, mainly at the first fruit positions and on lower fruiting branches. We observed significant differences of seed-cotton production between genotypes, with 'Celia' attaining the higher values, variety which presents more short season characters. The delaying of the planting date, while allowing better emergence and initial growth of the plants, shorten the available growing season and has a negative impact on seed cotton production. Thus, in Caia region, short season cultivars and early planting dates are best suited to cotton production, also being important to achieve high boll retention in the first positions and fruiting branches, in order to approach the boll growth and maturing period with more favourable environmental conditions. Fiber color grading shows no significant differences between varieties and planting dates, although differences were found in some of the commercial and technological quality measurements. With the present price and subsidies European Union context, the greater seed-cotton yield reach the profitability threshold.
With this work we pretend to contribute for the study of the growth, production and fibre quality of Gossypium hirsutum L. grown in ecological conditions of the Caia Irrigated Perimeter (Alentejo, Portugal). With this goal, two field trials were established at Herdade da Comenda (38º 54’ N, 7º 03’ W), in 2002 and 2003, using 6 varieties ('Carmen', 'Celia', 'Crema', 'Flora', 'Lacta' e 'Sonia'), of medium-short to medium-full season, sown at 3 planting dates (19/04, 30/04 and 16/05 in 2002, 20/03, 3/04 and 17/04 in 2003). We have found significant differences between genotype germination percentage with the cool (18ºC, 7 days) and the warm test (30ºC, 4 days), with 'Celia' and 'Sonia' showing the major vigor indices. Relative growth rate shows a decreasing tendency thereafter the first development stages, although net assimilation rate shows a tendency to increase until the end of July, decreasing thereafter continuously until the end of the season, with the leaf area index (LAI) increase and temperature and sunlight periods reduction. We don't observe any inter genotype or planting date differences between the day of the year of peaks LAI or crop growth rate (CGR), being maximal LAI reached 10 to 30 days latter then peak CGR. 'Celia' and the early planting date reached the lower node of first fruiting branch NFFB. Cutout (NAWF = 5) occurred between 20 July ('Celia' at the early planting date) and 19 August ('Flora' at the latter planting date), decreasing the number of days after sowing (DAS) to reach cutout with the delay of the planting date in all genotypes. The damages caused by Earias sp. and Heliothis/Helicoverpa, plagues that have resulted in high loose of fruiting forms, resulted in a high number of DAS to reach NAWF = 5, characteristic of plants with a insufficient boll load to determine assimilate diversion of vegetative growth. This circumstance, reinforced by inadequate temperatures to growth and maturation of bolls later set in season, resulted in poor harvest indexes and low retention, mainly at the first fruit positions and on lower fruiting branches. We observed significant differences of seed-cotton production between genotypes, with 'Celia' attaining the higher values, variety which presents more short season characters. The delaying of the planting date, while allowing better emergence and initial growth of the plants, shorten the available growing season and has a negative impact on seed cotton production. Thus, in Caia region, short season cultivars and early planting dates are best suited to cotton production, also being important to achieve high boll retention in the first positions and fruiting branches, in order to approach the boll growth and maturing period with more favourable environmental conditions. Fiber color grading shows no significant differences between varieties and planting dates, although differences were found in some of the commercial and technological quality measurements. With the present price and subsidies European Union context, the greater seed-cotton yield reach the profitability threshold.
Descrição
Palavras-chave
Elvas perímetro de riego del Caia Gossypium hirsutum L. variedades fechas de siembra análisis del crecimiento monitorización producción de algodón-bruto calidad de la fibra irrigated perimeter plant varieties planting dates growth analysis plant mapping seed-cotton yield fiber quality
Contexto Educativo
Citação
Barradas, G. J. P.A. (2004).ADAPTAÇÃO DE 6 VARIEDADES DE Gossypium hirsutum L. AO REGADIO DO CAIA. ANÁLISE DO CRESCIMENTO, PRODUÇÃO E QUALIDADE DA FIBRA . Tese Doutoramento apresentada na ESCUELA DE INGENIERÍAS AGRÁRIAS DEPARTAMENTO DE BIOLOGÍA Y PRODUCCIÓN DE LOS VEGETALES ÁREA DE PRODUCCIÓN VEGETAL. España Universida