Apple (Malus domestica) and pear (Pyrus communis) yield prediction after tree image analysis

Yield forecasting depends on accurate tree fruit counts and mean size estimation. This information is generally obtained manually, requiring many hours of work. Artificial vision emerges as an interesting alternative to obtaining more information in less time. This study aimed to test and train YOLO pre-trained models based on neural networks for the detection and count of pears and apples on trees after image analysis; while also estimating fruit size. Images of trees were taken during the day and at night in apple and pear trees while fruits were manually counted. Trained models were evaluated according to recall, precision and F1score. The correlation between detected and counted fruits was calculated while fruit size estimation was made after drawing straight lines on each fruit and using reference elements. The precision, recall and F1score achieved by the models were up to 0.86, 0.83 and 0.84, respectively. Correlation coefficients between fruit sizes measured manually and by images were 0.73 for apples and 0.80 for pears. The proposed methodologies showed promising results, allowing forecasters to make less time consuming and accurate estimates compared to manual measurements. Highlights The number of fruits in apple and pear trees, could be estimated from images with promising results. The possibility of estimating the fruit numbers from images could reduce the time spent on this task, and above all, the costs. This allow growers to increase the number of trees sampled to make yield forecasts.Yield forecasting depends on accurate tree fruit counts and mean size estimation. This information is generally obtained manually, requiring many hours of work. Artificial vision emerges as an interesting alternative to obtaining more information in less time. This study aimed to test and train YOLO pre-trained models based on neural networks for the detection and count of pears and apples on trees after image analysis; while also estimating fruit size. Images of trees were taken during the day and at night in apple and pear trees while fruits were manually counted. Trained models were evaluated according to recall, precision and F1score. The correlation between detected and counted fruits was calculated while fruit size estimation was made after drawing straight lines on each fruit and using reference elements. The precision, recall and F1score achieved by the models were up to 0.86, 0.83 and 0.84, respectively. Correlation coefficients between fruit sizes measured manually and by images were 0.73 for apples and 0.80 for pears. The proposed methodologies showed promising results, allowing forecasters to make less time consuming and accurate estimates compared to manual measurements. Highlights The number of fruits in apple and pear trees, could be estimated from images with promising results. The possibility of estimating the fruit numbers from images could reduce the time spent on this task, and above all, the costs. This allow growers to increase the number of trees sampled to make yield forecasts

Quantification of capillary water input to the root zone from shallow water table and determination of the associated Bartlett pear water status

The Alto Valle of Rio Negro and Neuquén is an intensive irrigated fruit producing area. The existence of a shallow water table modifies the water content in the soil profile. It is important to distinguish the effect and estimate the amount of water capillary rise in order to enhance the irrigation management and allow the crop to achieve its maximum yield and development in non-stress conditions. The aim of this trial was to quantify and associate water content of soil profile with water status of pear trees, using different methods. In a Bartlett pear orchard planted on 2003, surfaced irrigated, the following variables were measured during the 2017-2018 growing season: soil water content at three depths (0.20 m, 0.40 m, 0.60 m) and water table level (WTL). Additionally, soil profile and texture class were described. Evapotranspiration (ETm) and vapor pressure deficit (VPD) were calculated with data of the automatic weather station. Stomata conductance (Gs) was measured with a leaf porometer in three different moments of the growing season. Moisture stress index (MSI) was calculated from all Sentinel 2A images available for the season. The capillary water input into the root zone from a shallow water table is evident in the continuous records of sensors. This phenomenon keeps soil water content within the readily available water range. The Gs measures showed that the crop water status was appropriate and that values were high compared to those referred to deciduous trees. The MSI values obtained were between the limits of a well-irrigated crop. These results agree with the non-restrictive condition observed in the soil water balance.Sociedad Argentina de Informática e Investigación Operativ

Quantification of capillary water input to the root zone from shallow water table and determination of the associated Bartlett pear water status

The Alto Valle of Rio Negro and Neuquén is an intensive irrigated fruit producing area. The existence of a shallow water table modifies the water content in the soil profile. It is important to distinguish the effect and estimate the amount of water capillary rise in order to enhance the irrigation management and allow the crop to achieve its maximum yield and development in non-stress conditions. The aim of this trial was to quantify and associate water content of soil profile with water status of pear trees, using different methods. In a Bartlett pear orchard planted on 2003, surfaced irrigated, the following variables were measured during the 2017-2018 growing season: soil water content at three depths (0.20 m, 0.40 m, 0.60 m) and water table level (WTL). Additionally, soil profile and texture class were described. Evapotranspiration (ETm) and vapor pressure deficit (VPD) were calculated with data of the automatic weather station. Stomata conductance (Gs) was measured with a leaf porometer in three different moments of the growing season. Moisture stress index (MSI) was calculated from all Sentinel 2A images available for the season. The capillary water input into the root zone from a shallow water table is evident in the continuous records of sensors. This phenomenon keeps soil water content within the readily available water range. The Gs measures showed that the crop water status was appropriate and that values were high compared to those referred to deciduous trees. The MSI values obtained were between the limits of a well-irrigated crop. These results agree with the non-restrictive condition observed in the soil water balance.Sociedad Argentina de Informática e Investigación Operativ

Quantification of capillary water input to the root zone from shallow water table and determination of the associated Bartlett pear water status

The Alto Valle of Rio Negro and Neuquén is an intensive irrigated fruit producing area. The existence of a shallow water table modifies the water content in the soil profile. It is important to distinguish the effect and estimate the amount of water capillary rise in order to enhance the irrigation management and allow the crop to achieve its maximum yield and development in non-stress conditions. The aim of this trial was to quantify and associate water content of soil profile with water status of pear trees, using different methods. In a Bartlett pear orchard planted on 2003, surfaced irrigated, the following variables were measured during the 2017-2018 growing season: soil water content at three depths (0.20 m, 0.40 m, 0.60 m) and water table level (WTL). Additionally, soil profile and texture class were described. Evapotranspiration (ETm) and vapor pressure deficit (VPD) were calculated with data of the automatic weather station. Stomata conductance (Gs) was measured with a leaf porometer in three different moments of the growing season. Moisture stress index (MSI) was calculated from all Sentinel 2A images available for the season. The capillary water input into the root zone from a shallow water table is evident in the continuous records of sensors. This phenomenon keeps soil water content within the readily available water range. The Gs measures showed that the crop water status was appropriate and that values were high compared to those referred to deciduous trees. The MSI values obtained were between the limits of a well-irrigated crop. These results agree with the non-restrictive condition observed in the soil water balance.Sociedad Argentina de Informática e Investigación Operativ

Biochemical changes determination to predict the superficial scald development on pears

Durante la postcosecha de peras, se pueden expresar fisiopatias como escaldado superficial (ES). La misma, resulta de un proceso oxidativo, siendo la severidad proporcional al grado de oxidación de α-farnesenos (AF) a trienos conjugados (TC). El objetivo de este trabajo fue comprender los cambios bioquímicos que subyacen al desarrollo del ES y determinar los valores de umbral critico de TC en peras Beurré D´Anjou (BD), Packham´s Triumph (PT), Abate Fetel (AF), Rocha(R) y Williams (W). Los frutos se conservaron en frío convencional 240 días. Se determinó mensualmente: producción de etileno, parámetros de madurez, incidencia de ES, contenido de AF, TC, ácido ascórbico (AA), polifenoles (PF) y capacidad antioxidante total (DPPH). Los cultivares presentaron diferente susceptibilidad y patrón de manifestación de ES, correlacionado con el patrón de acumulación TC.  Las peras BD fueron las más sensibles a la escaldadura, con una pendiente de acumulación de TC mayor. En BD el umbral fue alto, intermedio en PT y bajo en W, R y AF. BD presentó los menores valores de DPPH, AA y PF a cosecha y durante el almacenamiento.  Las variedades de peras demostraron distinta sensibilidad a ES. Se estableció el umbral crítico para cada una.During pears postharvest disorders such as superficial scald (SS), can be developed. This disorder results of oxidative process, which severity is proportional to α-farnesenes (AF) oxidation degree to conjugated trienes (TC). The aim of this study was to characterize biochemical changes associated with the SS development and identify critical threshold values of TC in  Beurré D´Anjou (BD), Packham´s Triumph (PT), Abate Fetel (AF), Rocha (R) and Williams (W) pears.  The fruits were stored  on conventional storage for 240 days. Ethylene production, maturity indexes, SS incidence, AF, TC, Ascorbic Acid (AA) and Total Phenols content (TP) and total antioxidant capacity (DPPH), were determined every month.  The cultivars showed different susceptibility and SS manifestation pattern, correlated with TC accumulation pattern. Beurré D´Anjou pears were the most sensitive to SS and showed a greater TC accumulation slope. The critical threshold was high in BD, intermediate in PT and low in W, R and AF. At harvest and during storage,  BD presented the lowest values of DPPH, AA and PF.  The different pears varieties had different sensitivity to SS . The critical thresholds were determined for each pear variety.Facultad de Ciencias Agrarias y Forestale

Estrategias para reducir el daño por sol y aumentar la calidad de peras Beurre D'Anjou

El daño por sol ocasionado por altos niveles de radiación y temperatura es una de las principales causas de pérdida de calidad en peras y manzanas. Para el control del daño por sol se utilizan tecnologías para reducir la exposición de los frutos a elevadas temperaturas y a la radiación solar intensa. Se han evaluado diferentes tecnologías (hidrocooling, mallas de sombreo, mallas antigranizo, pulverización de materiales reflectantes) con resultados variables según especie, variedad y temporada. Además, se han desarrollado productos a base de fosfolípidos y polisacáridos, que suplementan la cutina y las capas cerosas que forman la cutícula, y así protegen a los frutos del estrés ambiental. Uno de ellos es Parka®, suplemento para la cutícula de la fruta a base de fosfolípidos de grado alimentario. El objetivo de este estudio fue evaluar el efecto de la posición de la fruta en la copa de los árboles y aplicaciones de Parka® sobre la incidencia y severidad de asoleado y la calidad de peras cv Beurre D´Anjou. El estudio se realizó durante dos temporadas (2020-21 y 2021-22) en una parcela ubicada en la EEA Alto Valle del INTA, plantada en el 2010 con un distanciamiento de 2 m por 4 m. Se realizaron tres tratamientos: 1) Testigo sol: peras de la parte externa de los árboles sin aplicaciones de Parka®; 2) Testigo sombra: peras de la parte interna de los árboles sin aplicaciones de Parka®; 3) Parka®: peras de la parte externa de los árboles con dos aplicaciones de Parka® (5 L/ha). Se cosecharon seis plantas por tratamiento y se determinó el porcentaje de daño por sol y la severidad, mediante una escala visual. Sobre una muestra de 100 frutos/tratamiento se midió la firmeza, color, sólidos solubles totales, acidez titulable y degradación del almidón. Se determinó en la piel de los frutos el contenido de ácido ascórbico, polifenoles, clorofila y capacidad antioxidante. Las aplicaciones de Parka® redujeron el porcentaje y severidad del daño por sol respecto a los tratamientos Testigos sol y sombra. La mayoría de los índices de madurez evaluados no presentaron diferencias entre tratamientos. Se observó un mayor contenido de ácido ascórbico y clorofila en la piel de las peras tratadas con Parka®. El contenido total de polifenoles, la capacidad antioxidante y peroxidación lipídica de membranas no mostraron diferencias entre tratamientos. Sin embargo, se observó un marcado aumento de estos tres parámetros bioquímicos en la temporada 2021-22. Los principales cambios en la calidad de la fruta (ácido ascórbico y clorofila) también estuvieron influenciados por las condiciones ambientales de las diferentes temporadas de crecimiento. Las aplicaciones del suplemento cuticular redujeron el daño por sol, por lo que podrían considerarse una alternativa interesante para mejorar la calidad de peras en regiones áridas.Facultad de Ciencias Agrarias y Forestale

Uso de malla antigranizo en pera cv. Forelle para mejorar calidad y reducir daños por asoleado

A nivel mundial, Argentina se posiciona como el tercer país productor y exportador de peras. Hasta 2021, en el Alto Valle de Rio Negro y Neuquén, había 18.266 ha. implantadas de este cultivo. Dos de las principales causas de pérdidas económicas y descarte, son los daños por sol y granizo. Ambos, han incrementado su incidencia en los últimos años como efecto del cambio climático, debido a una mayor frecuencia de granizadas y un aumento de las temperaturas máximas. El uso de mallas antigranizo es una alternativa para su control. Estas se colocan sobre estructuras de postes y alambres sobre los cuadros enteros. En el sistema de exclusión o multipropósito, las mallas se colocan sobre cada fila, brindando la cobertura de forma individual e independiente de las otras. Objetivo: evaluar el efecto de mallas antigranizo con sistema de exclusión sobre la calidad de pera Forelle a cosecha. Se cubrieron con malla mixta tres bloques de veinte plantas. Se marcaron tres bloques iguales como testigos. Durante dos temporadas, se midieron la productividad, el daño y grados de asoleado y los índices de madurez (color, firmeza, degradación de almidón, contenido de sólidos solubles y acidez). Se caracterizaron diferentes parámetros bioquímicos: capacidad antioxidante (% DPPH), polifenoles totales, ácido ascórbico, contenido de malondialdehído, antocianinas y clorofilas. Las mallas antigranizo redujeron significativamente el daño por sol y su severidad en las dos temporadas (p-valor <0,0001). A su vez, también redujo la concentración de sólidos solubles (p-valor = 0,0010**). El porcentaje de cobertura de color rojo (p-valor = 0,0486*) fue significativo entre tratamientos (p-valor=0,001). Para la temporada 2021 fue mayor en el testigo, pero en la siguiente fue mayor en la malla (p-valor= 0,018).  Para ambos tratamientos, el color fue mayor en valores de HUE para la temporada 2022 (p-valor <0,0001) y la acidez fue mayor en la temporada 2021 (p-valor = 0,008). De igual manera, la capacidad antioxidante (% DPPH) fue mayor en la fruta de la temporada 2021 (p-valor =0.0035) y el contenido de ácido ascórbico fue mayor en la temporada 2022 (p-valor<0.0001). El uso de mallas resulta una alternativa efectiva para atenuar el asoleado, pero redujo la concentración de solidos solubles, condicionando la calidad de la fruta. El efecto sobre los otros parámetros observados fue diferente y variable entre ambos años evaluados. Esto se relaciona a las condiciones ambientales de cada temporada, que presentaron un efecto sobre la calidad de la fruta más importante que el tratamiento evaluado. Más estudios serán necesarios para seguir caracterizando este cultivo.Facultad de Ciencias Agrarias y Forestale