Abstract This paper presents an innovative modified method of K-means clustering based on the set theory together with its application in the processing images of the agroindustry field. Traditional K-means permits the clustering of sets in subsets by means of defining their center according to the distance formula. When the data is concentrated in forms without a hyper-spherical sense, this tool allows the center of the set, with a single point, to become a subset of many points. In this article we present a modification of the distance formula that allows giving more flexibility for the study of cases in agriculture. Using numerical examples, the functionality and applicability of the modified method of K-means grouping is evaluated in infrared images from water deficit tests in wheat.

Resumen Este trabajo presenta un innovador método de agrupación K-media modificado basado en la teoría de conjunto junto con su aplicación en el ámbito de procesamiento de imágenes agroindustrial. K-media tradicional permite la agrupación de conjuntos en subconjuntos mediante la definición de centros según la fórmula de distancia. Cuando los datos se concentran en formas sin un sentido hiper-esférico, esta herramienta permite que el centro del conjunto, con un único punto, se convierta en un subconjunto de muchos puntos. En este artículo se presenta una modificación de la fórmula de distancia que permite dar mayor flexibilidad para el estudio de casos en agricultura. Mediante ejemplos numéricos, la funcionalidad y aplicabilidad del método modificado de agrupación K-media es evaluada en imágenes infrarrojas provenientes de ensayos de déficit hídrico en trigo.

W. Lindberg, E. Hanson, and G.A. Lobos. 2014. Partial inhibition of flowering in young highbush blueberries with gibberellins. Cien. Inv. Agr. 41(3):349-356. Preventing young blueberry (Vaccinium corymbosum L.) plants from fruiting can increase their vegetative growth. In previous studies, gibberellin (GA) applications reduced flowering in highbush blueberry, but the response was variable and cultivar dependent and was studied mostly using potted nursery plants. The purpose of this work was to determine whether floral induction can be inhibited by GA in plants established in the field, particularly on newer cultivars now being widely planted. Foliar sprays were applied in several experiments with different application intervals and concentrations; the efficacy was determined by counting the number of initiated floral meristems. GA applications in July and August were more inhibitive than those in September and October, while cultivars did not vary in their response. GA significantly reduced flower bud numbers in three separate studies, but the greatest reduction (49%) required repeated applications from July to October. The results indicate that GA may have limited commercial utility for preventing fruiting in highbush blueberries under field conditions. However, further studies are needed to determine how vegetative growth is affected by the partial inhibition of flowering.

W. Lindberg, E. Hanson y G.A. Lobos. 2014. Inhibición parcial de la floración en plantas jóvenes de arándanos con giberelinas. Cien. Inv. Agr. 41(3):349-356. La inhibición de la fructificación en plantas jóvenes de arándanos (Vaccinium corymbosum L.) puede mejorar el crecimiento vegetativo. En estudios previos, en su mayoría en plantas de vivero en macetas, de mostró que la aplicación de giberelinas (GA) redujo la floración en arándanos de arbusto alto, pero la respuesta fue variable y dependiente del cultivar. El objetivo de este trabajo fue determinar si la inducción floral puede ser inhibida por GA en plantas jóvenes en campo, especialmente en nuevos cultivares que están siendo ampliamente plantados. En diversos experimentos se hicieron aplicaciones foliares con distintos intervalos y concentraciones; la eficacia se midió contando el número de meristemas diferenciados. Aplicaciones de GA en julio y agosto inhibieron más que aquellas de septiembre y octubre, mientras que el cultivar no fue dependiente. GA disminuyó significativamente el número de yemas florales en los tres estudios, pero el mayor efecto (49%) requirió de aplicaciones consecutivas desde julio a octubre. Los resultados indican que GA puede tener una limitada utilidad comercial para prevenir la fructificación en arándanos de arbusto alto en condiciones de campo. Sin embargo, se requiere de mayor investigación para determinar como el crecimiento vegetativo es afectado por una inhibición parcial de la floración.

Applications of N-(2-chloro-4-pyridyl)-N’-phenylurea (CPPU) can increase blueberry (Vaccinium corymbosum L.) yield and fruit size, but their impact on postharvest is unknown. We studied repeated CPPU applications effects on yield and quality (harvest, postharvest), over 2 yr on mature ’Duke’ plants in South-Central Chile. The first year, 5 or 10 mL L-1 CPPU was applied at 3, 10, and/or 17 d after full bloom (DAFB) plus a non-sprayed control. The second year, 5 or 10 mL L-1 CPPU were sprayed 10 and 17 DAFB plus a control. The first year, only 10 mL L-1 CPPU sprayed 3+17 DAFB increased yield (32.5% > control); 10 mL L-1 CPPU applied 10 or 3+17 DAFB had highest fruit diameter; and 10 mL L-1 CPPU at 17 DAFB or at 3+10+17 DAFB had highest soluble solids. Overall, 10 mL L-1 CPPU applied 3+17 DAFB, was the best treatment for year one, since it increased fruit yield and diameter, while soluble solids and postharvest weight loss were similar to control. The second year, 10 mL L-1 CPPU reduced fruit coloration (blue color coverage index: BCCI) and soluble solids, but not firmness at harvest. This rate increased berry weight (24.2%) and fruit wax (59% > wax coverage index: WCI) at harvest. Harvest and postharvest WCI increased consistently as CPPU rate increased. CPPU reduced fruit rotting (15% at 45+5 evaluation). During storage, CPPU-treated-fruit had a slower decrease in firmness (30.5% < control at 30+1), but no difference at 30+5. CPPU-treated-fruit usually had higher post harvest soluble solids. Ten mL L-1 CPPU retarded color evolution at harvest and at 30+1, but not at 30+5, 40+1 or 40+5.

O Chile tornou-se de grande atuação na indústria de Mirtilo como o fornecedor mais importante de frutas frescas de entressafra para o hemisfério Norte. Exportações de Mirtilo passaram de $ 30 milhões de dólares americanos (cerca de 4.000 toneladas) em 2000, para 380 milhões (94 mil toneladas) em 2011. As características das principais regiões de cultivo de Mirtilo (Norte, Central, Centro-Sul e Sul) säo apresentados em termos de área plantada, variedades, práticas de manejo, extensäo do período de colheita, e condições climáticas e do solo. A maioria das frutas é de variedades highbush, colhidas à mäo e exportados frescas para os Estados Unidos por barco.Grande porcentagem do fruto é exportada a partir de meados de dezembro até o final de janeiro, que coincide com preços mais baixos. A regiäo Centro-sul (latitude 34º 50' a 38º15' S), foi em 2007 a mais importante, com 5.075 ha (51,1% da área plantada). Entre os desafios da indústria de Mirtilo no Chile em um futuro próximo säo: 1. Baixa rentabilidade devido à diminuição das taxas de câmbio e custos mais altos, 2. Maior escassez e aumento do custo da mäo-de-obra, 3. Necessidade de uma maior produtividade e práticas de produção sustentável, 4. Fruta de alta e consistente qualidade, e 5. Maior investimento em pesquisa. Como estudo de caso o artigo apresenta três abordagens que podem ajudar a identificar as áreas com baixa disponibilidade de mäo de obra e melhorar a sua eficiência. O artigo mostra o uso de ferramentas de geomática para estabelecer a disponibilidade de mäo-de-obra, a aplicação de reguladores de crescimento para reduzir a carga das culturas, aumentar o tamanho dos frutos e melhorar a eficiência da colheita, bem como a utilização de sacudidores para colher frutas frescas para os mercados de longa distância. Mais pesquisas säo necessárias para melhorar o rendimento, reduzir custos e dar maior sustentabilidade econômica e ecológica para a indústria de Mirtilo do Chile.

Chile has become a major actor in the blueberry industry as the most important supplier of off-season fresh fruit for the northern hemisphere. Blueberry exports passed from US$ 30 million (around 4,000 tons) in 2000 to US$ 380 million (94,000 tons) in 2011. The characteristics of the major blueberry growing regions (North, Central, South-central and South) are presented in terms of acreage, varieties, management practices, extension of the harvest season, and soil and climatic conditions. Most fruit is from highbush varieties, picked by hand and exported fresh by boat to United States. Largest proportion of fruit is exported from mid December to late January, which coincides with lowest prices. The south-central region (latitudes 34º50' to 38º15' S) was in 2007 the most important one with 5,075 ha (51.1% of area planted). Among the challenges for the Chilean blueberry industry in the near future are: 1. Lower profitability due to lower rates of currency exchange and higher costs, 2 - Greater scarcity and higher cost of labor, 3.- Need for higher productivity and sustainable production practices, 4- Fruit of high and consistent quality, and 5.- Greater investment in research. As a case study the article presents three approaches that can help identify areas with low availability of labor and improve its efficiency. The article shows the use of geomatic tools to establish labor availability, application of growth regulators to reduce crop load, increase fruit size and improve harvest efficiency, and the use of shakers to harvest fresh fruit for long distance markets. More research is needed to improve yields, reduce costs and give greater economical and ecological sustainability to the Chilean blueberry industry.

The Chilean forest industry represents the second source of incomes, after copper, where Pinus radiata is the major cultivated species; this production level has generated new alternatives searching to increase the quality of pine seedlings. The use of organic sources of fertilization and the use of fungi, like Trichoderma harzianum, arise as production alternatives. This study evaluated plant growth stimulation activity of native strain of T. harzianum on Pinus radiata seedling and the effect of compost as substratum in the interaction of these organisms, both plant (fitness) and fungus (population). The results indicated a positive significant interaction between T. harzianum and compost over height and biomass of the plants, as well as in the development of the radical system, by the combination of compost and T. harzianum. Compost increases the size and population rate of T. harzianum. Compost substratum inoculated with T. harzianum increases significantly the fitness of P. radiata seedling. The involved mechanisms have not been elucidated

La industria forestal en Chile representa la segunda fuente de divisas, donde Pinus radiata es la principal especie cultivada, lo que ha generado la búsqueda de nuevas alternativas para incrementar tanto la producción como la calidad de las plántulas. Entre éstas se encuentran el uso de fuentes orgánicas de fertilización y el uso de hongos como Trichoderma harzianum. Este estudio pretende determinar la capacidad estimulante de una cepa nativa de T harzianum sobre plántulas de Pinus radiata y el efecto del uso de compost como sustrato sobre esta interacción, tanto desde el punto de vista de la planta (vigor) como del hongo (poblacional). Los resultados obtenidos indican que la presencia conjunta de compost y T harzianum permite un incremento significativo en altura y biomasa de las plantas, así como el desarrollo del sistema radical. Por su parte, la presencia de compost estimula un incremento poblacional del hongo T harzianum, indicando que la inoculación de los sustratos utilizados para producción de plántulas de P. radiata con T harzianum generaría un incremento significativo en el vigor de las plántulas producidas. Los mecanismos involucrados no han sido dilucidados