Evaluation of growth regulators asthinners on "Thompson Seedless" table grapes clusters

Se evaluó el uso de reguladores de crecimiento complementarios al ácido giberélico (GA3), como raleadores de flores y bayas en uva de mesa "Thompson Seedless", en las regiones de Atacama y Metropolitana, Chile. Se utilizó ácido naftalén acético (NAA), tidiazurón (TDZ), y benciladenina (BA) en plena floración; y Wuxal® Ca en baya de 3-4mm. Durante la primera temporada, se prospectaron dosis de NAA: 0; 2,5; 5; 7,5; 10 y 12,5 mg·L-1; BA: 0; 60; 90; 120; 150 y 180 mg·L-1 y TDZ: 0; 0,5; 1; 1,5 y 2 mg·L-1. En la segunda temporada, se probó NAA: 0; 2,5; 5 y 7,5 mg·L-1 y BA: 0; 150; 300; 450 y 600 mg·L-1. En un tercer ensayo, se aplicó 2 mg·L-1 de NAA en floración, y posteriormente Wuxal® Ca a 18 y 36 cm3·L-1, en cuaje. El NAA disminuye el número de bayas por racimo, mostrando fitotoxicidad con dosis mayores a 7,5 mg·L-1. El TDZ no demuestra efecto raleador y BA genera racimos más compactos a mayor concentración. Wuxal® Ca aplicado después del NAA, disminuye el número de bayas por racimo, ampliando el período de raleo hasta etapas posteriores al cuaje.In order to evaluate in the Region de Atacama and Region Metropolitana from Chile, the use of complementary thinners to the gibberellic acid (GA3) applied to "Thompson Seedless" grapes. This research explored the use of naphthalene acetic acid (NAA), thidiazuron (TDZ) and benzyladenine (BA) applied to flowering plants; and Wuxal® Ca in the fruit set. During the first season, prospective assays were performed. NAA was sprayed at: 0; 2.5; 5; 7.5; 10 and 12.5 mg·L-1; BA tested concentrations were: 0, 60, 90, 120, 150 and 180 mg·L-1, and TDZ concentrations were: 0; 0.5; 1; 1.5 and 2 mg·L-1. During the second season, NAA was sprayed at 0; 2.5; 5.0 and 7.5 mg·L-1 and BA was applied at 0, 150, 300, 450 and 600 mg·L-1. On a thirth trial, 2 mg·L-1 of NAA and Wuxal® Ca applied at bloom and fruit set, respectively. NAA decreased the number of berries for cluster; phytotoxicity was detected at concentration since 7.5 mg·L-1. BA increased berry number with higher concentrations. TDZ did not show differences in thinning. Wuxal® Ca applied after NAA, decreased berry number per cluster, extending the effective period of thinning until after fruit set.Fil: Arancibia Urzúa, Gonzalo Nicolás. Universidad de Chile. Facultad de Ciencias Agronómicas.Fil: Rodríguez Callejas, Rodrigo. Universidad de Chile. Facultad de Ciencias Agronómicas. Departamento de Producción Agrícola. FruticulturaFil: Reginato Meza, Gabino. Universidad de Chile. Facultad de Ciencias Agronómicas. Departamento de Producción Agrícola. Fruticultur

Evaluación de reguladores de crecimiento como raleadores en racimos de 'Thompson Seedless'

In order to evaluate in the Region de Atacama and Region Metropolitana from Chile, the use of complementary thinners to the gibberellic acid (GA3) applied to 'Thompson Seedless' grapes. This research explored the use of naphthalene acetic acid (NAA), thidiazuron (TDZ) and benzyladenine (BA) applied to flowering plants; and Wuxal® Ca in the fruit set. During the first season, prospective assays were performed. NAA was sprayed at: 0; 2.5; 5; 7.5; 10 and 12.5 mg"¢L-1; BA tested concentrations were: 0, 60, 90, 120, 150 and 180 mg"¢L-1, and TDZ concentrations were: 0; 0.5; 1; 1.5 and 2 mg"¢L-1. During the second season, NAA was sprayed at 0; 2.5; 5.0 and 7.5 mg"¢L-1 and BA was applied at 0, 150, 300, 450 and 600 mg"¢L-1. On a thirth trial, 2 mg"¢L-1 of NAA and Wuxal® Ca applied at bloom and fruit set, respectively. NAA decreased the number of berries for cluster; phytotoxicity was detected at concentration since 7.5 mg"¢L-1. BA increased berry number with higher concentrations. TDZ did not show differences in thinning. Wuxal® Ca applied after NAA, decreased berry number per cluster, extending the effective period of thinning until after fruit set.Se evaluó el uso de reguladores de crecimiento complementarios al ácido giberélico (GA3), como raleadores de flores y bayas en uva de mesa 'Thompson Seedless', en las regiones de Atacama y Metropolitana, Chile. Se utilizó ácido naftalén acético (NAA), tidiazurón (TDZ), y benciladenina (BA) en plena floración; y Wuxal® Ca en baya de 3-4mm. Durante la primera temporada, se prospectaron dosis de NAA: 0; 2,5; 5; 7,5; 10 y 12,5 mg"¢L-1; BA: 0; 60; 90; 120; 150 y 180 mg"¢L-1 y TDZ: 0; 0,5; 1; 1,5 y 2 mg"¢L-1. En la segunda temporada, se probó NAA: 0; 2,5; 5 y 7,5 mg"¢L-1 y BA: 0; 150; 300; 450 y 600 mg"¢L-1. En un tercer ensayo, se aplicó 2 mg"¢L-1 de NAA en floración, y posteriormente Wuxal® Ca a 18 y 36 cm3"¢L-1, en cuaje. El NAA disminuye el número de bayas por racimo, mostrando fitotoxicidad con dosis mayores a 7,5 mg"¢L-1. El TDZ no demuestra efecto raleador y BA genera racimos más compactos a mayor concentración. Wuxal® Ca aplicado después del NAA, disminuye el número de bayas por racimo, ampliando el período de raleo hasta etapas posteriores al cuaje

A model for canning peach crop value using a software for dynamic modeling

In order to optimize fruit thinning of canning peaches, considering yield and pulp fraction or canned fruit as a function of crop load, a model to estimate crop value was built using the software Stella®. Since crop value depends on fruit weight, size distribution and total yield, the relationships were estimated from experimental data collected over 10 years with different cultivars and orchards. The model estimates average fruit weight as a function of crop load, fruit set, thinning date, harvest date (cultivar) and maturity. The degree of maturity at harvest is defined as pulp firmness. Size distribution is estimated from the average fruit weight, considering three commercial categories: “for pulping”, “for canning” and “oversized fruit”. Total yield is based on fruits tree-1, trees ha-1 and fraction of intercepted radiation. The intercepted radiation of each situation is estimated from the coverage of the largest and the smallest tree, assuming a normally distributed population. Prices can be modified to generate different scenarios based on the requirements and allowances set by the industry. Although the validation of the model has not yet been done, the model can be a promising tool for determining the thinning strategy for canning peach by understanding and quantifying the yield response to crop load

Evaluación de raleadores químicos en manzanos var. Braeburn.

Se ensayó, durante la temporada 1996-1997, en Colchagua, VI Región, Chile (34º38' lat. S.; 71º06' long. O.) en manzanos Braeburn/MM106, de 7 años, el efecto raleador del ácido naftalén acético (ANA), 2,5; 5,0 y 7,5 mg L-1 en botón rosado (BR) y carbaril (60 y 120 g i.a. 100 L-1) en caída de pétalos (CP) o diez días después (10ddCP). Además se asperjaron combinados, pero diferidamente, 2,5 y 5 de ANA en BR y carbaril 60 ó 120 en CP. Cada tratamiento fueron 4 árboles en un arreglo completamente aleatorizado. Además se efectuó un análisis de varianza con estructura factorial 3x3 (0; 60; 120 carbaril; 0; 2,5; 5,0 ANA). Posterior a las caídas naturales, se evaluó el efecto raleador según carga inicial. Todos los tratamientos redujeron la carga respecto del testigo, excepto carbaril 60, 10 ddCP, y 7,5 ANA. Ningún tratamiento presentó sobrerraleo. En general, las aplicaciones tempranas de carbaril (CP) mostraron mayor efecto sobre el tamaño de frutos que aplicaciones tardías. El tratamiento de ANA que más benefició el tamaño del fruto fue 5,0 mg L-1 en BR. En los tratamientos combinados se observó que 5,0 ANA efectivamente aumenta el tamaño de frutos, sin diferencias debidas a carbaril. Buena correlación existió entre carga inicial y el peso de frutos (R2 = 0,69), no así entre ésta y retorno floral. Sólo con carbaril hubo alguna respuesta del retorno floral con la reducción de la carga frutal

Poda de formación y producción

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Pistillate flower abscission symptoms of 'Serr' walnut (Juglans regia L.)

Pistillate flower abscission (PFA) severely affects walnut (Juglans regia L.) production, mainly of the cultivar 'Serr'. A study on symptoms of flower abortion in walnut 'Serr', induced by excess or lack of pollen, was carried out following the evolution of flowers and peduncles. Hand pollinated flowers, with different pollen concentrations: 0, 1, 5, 25, 50 and 100% pollen diluted(w/w) in talcum powder, showed external and internal abortion symptoms. External symptoms were recorded directly from the tree, whilefor internal symptoms, flower excisions stained with blue toluidin-O at 0.05%, were analyzed under an optical microscope. Excess pollen abortion produced flowers with rapid damage. The growth rate was very low, involucre brightness was lost and the stigma tamed necrotic, in contrast to the flower aborted from lack of pollen. Normal flowers continued growing to fruit harvest, without losing brightness. Excess pollen abortion induced flower drop, with or without attached peduncle. Two separation zones call be present: the distal and proximal areas of the peduncle. Peduncle scars allowed for differentiating abortion induced from excess or lack of Pollen, or other reasons

Modelling physiological and environmental factors regulating relative fruit set and final fruit numbers in apple trees

Chemical thinning of apple (Malus domestica Borkh.) has been practised for 50 years but it remains an unpredictable part of apple production with large variations from year to year and within years. Carbohydrate availability to support young fruitlet growth may play a significant role in apple tree response to chemical thinners, especially when the carbohydrate supply is the limiting factor for fruit growth. To address the carbohydrate component, we have tested the MaluSim model that integrates many environmental and tree physiological factors as a tool to predict chemical thinner response. The model suggests that carbon supply-to-demand variations may explain some of the great variations in thinning spray response. Relative fruit set and final fruit number per tree were affected by the carbohydrate balance within 2 days before the spray and up to 5 days after. There was a period, 15-29 days after bloom that thinners showed higher action. The greater the carbohydrate supply relative to demand, the greater the relative set and the final fruit number. This suggested that carbohydrate supply-demand balance may be a baseline for thinner responses, and that integrative modelling of these balances can be useful in understanding variation in thinning responses. Apple relative fruit set and final fruit number per tree could be modelled relatively well with consideration of initial flower density, the carbohydrate balance model, and cumulative growing degree-days since bloom.New York Apple Research Development Program. Federal Formula Hatch funding. New York State base funding

Natural fruitlet abscission as related to apple tree carbon balance estimated with the MaluSim model

Apple trees produce many more flower clusters than needed for a full crop, but natural early season flower and fruitlet abscission drastically reduce the final fruit number. Natural fruit abscission varies significantly year to year. There have been attempts to try to model apple fruit abscission in the past. However, due to the great complexity of a perennial crop system in a dynamic environment with significant plant manipulations, regulatory processes and controlling environmental variables have been difficult to elucidate. In 1995, a field trial was planted at the New York State Agricultural Experiment Station in Geneva, New York with 3 apple cultivars (‘Delicious’ ‘Gala’ and ‘McIntosh’). Beginning in 2000 and for 18 years thereafter, we recorded the natural whole-season fruit abscission of untreated trees that received no chemical or hand thinning. We also estimated early season patterns of carbohydrate supply-to-demand each year with a carbon balance model. These data were used to correlate tree carbon balance status and other environmental variables with natural fruit abscission responses. In general terms, natural set, defined as final fruit/flower cluster, of ‘Gala’ averaged ˜1 fruit for each flower cluster (fruit set = 0.9), whereas fewer fruits were set on ‘Delicious’ and ‘McIntosh’ (fruit set = 0.7 and 0.6, respectively). Fruit set of ‘Gala’ was less variable than of ‘Delicious’ or ‘McIntosh’ and there was a clear pattern for decreasing fruit set when the number of initial flower clusters per tree increased. Fruit weight was less dependent on fruit number for ‘Delicious’ and ‘McIntosh’ than for ‘Gala’. Multiple regression models indicated that number of flower clusters per tree and average carbohydrate balance between 0–60 degree days (DD) after bloom and 300–360 DD after bloom were the main significant variables that explained 60–80% of the variability in natural fruit set or final fruit number. For ‘Delicious’ temperatures of the previous fall also explained a significant amount of variation in final fruit set and final fruit number. For ‘Gala’ carbon balance from bloom to shortly after petal fall and when fruits were about 18 mm were the two main periods, which were more sensible to carbohydrate deficiency triggering fruit abscission. A later susceptible period was also observed for ‘McIntosh’ suggesting a larger thinning window for this cultivar