Respuestas Productivas y Fisiológicas del Cerezo (Prunus avium L.) Protegido Bajo Mallas
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Date
2024
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Publisher
Universidad de Concepción
Abstract
El cerezo (Prunus avium (L.) L.) es un frutal con alta demanda de sus frutos por parte de los consumidores. Producto de ello se ha registrado en los últimos años un aumento de la superficie con este cultivo a nivel global. Sin embargo, las condiciones meteorológicas inestables producto del cambio climático generan incertidumbre para los agricultores, que ha llevado al cultivo de este frutal en ambientes protegidos. Estos sistemas productivos se basan en el uso de materiales de cobertura tales como plástico y rafia principalmente para prevenir daños en la floración y frutos por eventos de lluvias, heladas y granizadas. Además, en la actualidad se están incorporando mallas para mitigar efectos dañinos de las olas de calor y escasez hídrica. Dependiendo de las características del material empleado, el uso de cubertura altera las condiciones micro-climáticas del huerto, aunque esta situación es sabida, existe escaso conocimiento sobre cómo estas condiciones alteran parámetros productivos y fisiológicos en el cerezo.
La presente tesis doctoral tuvo como objetivo determinar y profundizar en aspectos productivos y fisiológicos que se ven alterados en huertos de cerezo protegidos bajo coberturas, con énfasis en el uso de mallas. En una primera etapa se realizó una revisión del estado del arte sobre los factores ambientales (luz, temperatura, humedad relativa y viento) involucrados en la producción de cerezos bajo diferentes tipos de cubiertas y su efecto en las respuestas fisiológicas del árbol (intercambio gaseoso de la hoja, relaciones hídricas, desarrollo floral, crecimiento y desarrollo del árbol, y caracteres de calidad de frutos). Como principales conclusiones de esta revisión se determinó que todas las cubiertas utilizadas en cerezo aumentan la proporción de radiación fotosintéticamente activa (PAR) del tipo difusa, disminuyendo el exceso de PAR directa con un resultado positivo en la actividad fotosintética. Sin embargo, esta menor PAR directa genera un desbalance en el crecimiento del árbol, a favor del desarrollo vegetativo en desmedro del reproductivo. En cerezos bajo cubierta también se observa un aumento e la temperatura que afectaría negativamente el potencial de cuajado de frutos y el rendimiento, pero con impacto positivo en el crecimiento de los frutos. Por otra parte, el uso de cubiertas estaría favoreciendo el estado hídrico del árbol, pero que alteraría el flujo de nutrientes específicos como calcio y a través de ello la firmeza de frutos. Se sugiere que es necesario ajustar las prácticas agronómicas de manejo en huertos de cerezo protegidos de acuerdo a las condiciones micro-climáticas y respuestas fisiológicas particulares que existen bajo las cubiertas.
En una segunda etapa, se investigó el efecto de mallas foto-selectivas de color azul gris (AG) con dos densidades de trama y urdiembre: 4 hilos x 4 hilos por cm-1 lineal (AG4x4) y 5 hilos x 5 hilos por cm-1 lineal (AG5x5), en un huerto comercial de cerezo de los cultivares Kordia y Regina, establecidos en la localidad de Camarico, Región del Maule, y durante dos temporadas consecutivas. Se evaluó su efecto en las condiciones de luz, intercambio gaseoso de la hoja, desarrollo floral, producción y caracteres de calidad de frutos. Ambas mallas redujeron la densidad de flujo de fotones fotosintéticos (PPFD) en un 24% y 30% para AG4x4 y AG5x5, respectivamente. La eficiencia de uso de la luz, determinada como la relación entre la asimilación neta de CO2 (An) y PPFD se incrementó por el uso de estas mallas en un 73% y 76% para los cultivares Kordia y Regina, respectivamente. En cuanto al desarrollo floral, la malla AG5x5 redujo el número de yemas y primordios florales por yema en 20%, pero con efecto positivo en el tamaño de los frutos, el que aumentó en un 4% y 12% para los cultivares Kordia y Regina respectivamente. Nuestros resultados indican que el uso de malla fotoselectiva AG en huerto de cerezo sería una herramienta útil para optimizar la asimilación neta de CO2 de la hoja y regular la carga frutal en este cultivo, en tanto su efecto sobre caracteres de calidad de frutos se encuentra fuertemente influenciado por el cultivar y las condiciones ambientales.
Sweet cherry (Prunus avium (L.) L.) fruit is in high demand by consumers. As a result, there has been an increase in the global area under this crop in recent years. However, unstable weather conditions due to climate change have created uncertainty for cherry growers, making it necessary to produce this fruit tree in a protected environment. Cherry tree production in a protected environment is based on the use of covering materials such as plastic and woven with the main objective of preventing damage to the blossom and fruit due to rain, frost, and hailstorms. Other alternatives are currently being incorporated such as nets to mitigate the harmful effects of heat waves and water shortages. Depending on the characteristics of the material used, the use of coverings alters the microclimatic conditions of the orchard, but there is little knowledge on how these conditions alter the productive and physiological parameters of cherry trees. The aim of this doctoral thesis was to identify and study in depth the productive and physiological aspects that are modified in cherry orchards protected by different types of cover, with particular emphasis on the use of netting. The first phase encompassed a comprehensive review of the current understanding of environmental factors such as light, temperature, relative humidity and wind involved in the production of cherry trees under different types of cover. This review also examined their effect on the physiological responses of the trees including leaf gas exchange, water relations, flower development, tree growth and development and fruit quality traits. The main conclusions of this review were that using covers used on cherry trees increases the proportion of diffuse photosynthetically active radiation (PAR) and reduces the excess of direct PAR, which has a positive impact on the photosynthetic activity of the plant. However, this reduction in direct PAR leads to an imbalance in tree growth, promoting vegetative development at the expense of reproductive development. In addition, cherry trees under covers increase air temperature, which would have a negative effect on fruit set and yield, but a positive effect on fruit growth. On the other hand, the use of covers would benefit the water status of the tree, but would alter the flow of specific nutrients such as calcium and thus fruit firmness. It is suggested that is necessary to adapt the agronomic management of cherry orchards protected under covering to the specific microclimatic conditions and physiological responses that exist under cover materials. The second phase involved the effect of photo-selective blue-grey (AG) netting with two weft and warp densities: 4 threads x 4 threads per linear cm-1 (AG4x4) and 5 threads x 5 threads per linear cm-1 (AG5x5), was studied in a commercial cherry orchard of Kordia and Regina cultivars, located in the locality of Camarico, Maule region, during two consecutive seasons. Their effect on light conditions, leaf gas exchange, flower development, yield and fruit quality characteristics was evaluated. Both nets reduced the photosynthetic photon flux density (PPFD) by 24% and 30% for AG4x4 and AG5x5, respectively. Light use efficiency, determined as the ratio of net CO2 assimilation rate (An) to PPFD, was increased by 73% and 76% under netting for the Kordia and Regina cultivars, respectively. In terms of flower development, the AG5x5 net reduced the number of buds and flower primordia per bud by 20%, but had a positive effect on fruit size, which increased by 4% and 12% for the Kordia and Regina cultivars, respectively. Our results indicate that the use of AG photo-selective netting in cherry orchards would be a useful tool to optimize net leaf CO2 assimilation and regulate fruit load in this fruit crop, while its effect on fruit quality traits is strongly influenced by cultivar and environmental conditions.
Sweet cherry (Prunus avium (L.) L.) fruit is in high demand by consumers. As a result, there has been an increase in the global area under this crop in recent years. However, unstable weather conditions due to climate change have created uncertainty for cherry growers, making it necessary to produce this fruit tree in a protected environment. Cherry tree production in a protected environment is based on the use of covering materials such as plastic and woven with the main objective of preventing damage to the blossom and fruit due to rain, frost, and hailstorms. Other alternatives are currently being incorporated such as nets to mitigate the harmful effects of heat waves and water shortages. Depending on the characteristics of the material used, the use of coverings alters the microclimatic conditions of the orchard, but there is little knowledge on how these conditions alter the productive and physiological parameters of cherry trees. The aim of this doctoral thesis was to identify and study in depth the productive and physiological aspects that are modified in cherry orchards protected by different types of cover, with particular emphasis on the use of netting. The first phase encompassed a comprehensive review of the current understanding of environmental factors such as light, temperature, relative humidity and wind involved in the production of cherry trees under different types of cover. This review also examined their effect on the physiological responses of the trees including leaf gas exchange, water relations, flower development, tree growth and development and fruit quality traits. The main conclusions of this review were that using covers used on cherry trees increases the proportion of diffuse photosynthetically active radiation (PAR) and reduces the excess of direct PAR, which has a positive impact on the photosynthetic activity of the plant. However, this reduction in direct PAR leads to an imbalance in tree growth, promoting vegetative development at the expense of reproductive development. In addition, cherry trees under covers increase air temperature, which would have a negative effect on fruit set and yield, but a positive effect on fruit growth. On the other hand, the use of covers would benefit the water status of the tree, but would alter the flow of specific nutrients such as calcium and thus fruit firmness. It is suggested that is necessary to adapt the agronomic management of cherry orchards protected under covering to the specific microclimatic conditions and physiological responses that exist under cover materials. The second phase involved the effect of photo-selective blue-grey (AG) netting with two weft and warp densities: 4 threads x 4 threads per linear cm-1 (AG4x4) and 5 threads x 5 threads per linear cm-1 (AG5x5), was studied in a commercial cherry orchard of Kordia and Regina cultivars, located in the locality of Camarico, Maule region, during two consecutive seasons. Their effect on light conditions, leaf gas exchange, flower development, yield and fruit quality characteristics was evaluated. Both nets reduced the photosynthetic photon flux density (PPFD) by 24% and 30% for AG4x4 and AG5x5, respectively. Light use efficiency, determined as the ratio of net CO2 assimilation rate (An) to PPFD, was increased by 73% and 76% under netting for the Kordia and Regina cultivars, respectively. In terms of flower development, the AG5x5 net reduced the number of buds and flower primordia per bud by 20%, but had a positive effect on fruit size, which increased by 4% and 12% for the Kordia and Regina cultivars, respectively. Our results indicate that the use of AG photo-selective netting in cherry orchards would be a useful tool to optimize net leaf CO2 assimilation and regulate fruit load in this fruit crop, while its effect on fruit quality traits is strongly influenced by cultivar and environmental conditions.
Description
Tesis presentada para optar al grado de Doctora en Ciencias de la Agronomía
Keywords
Cambio climático, Cerezo - Chile, Frutales