Stanislav Tojnko

Effect of location in the canopy on the colour development of three apple cultivars during growth

BACKGROUND Homogeneity in appearance is one of the quality aspects asked for in the supply chain. Decreasing the biological variation in batches of harvested apples (cultivars Braeburn, Fuji and Gala) becomes increasingly important. Skin colour is one of the aspects that determine both optimal harvest and stage of development. Skin colour is affected by location in the canopy. The rules of development of biological variation are now established and will be used on skin colour data. RESULTS The Minolta colour aspects a*, b* and L* measured before commercial harvest change in a sigmoidal fashion and can be analysed including the biological variation, with a logistic model in indexed nonlinear regression, obtaining explained parts of above 90%. The mechanism of colour change is not affected by state of development or location in the canopy. The location in the canopy affects the intensity of both red and green colouring compounds. The variation in colouration is not affected by the location in the canopy. CONCLUSION The red-coloured apple cultivar (Gala) depends more on the location in the canopy than the less-coloured cultivars (Fuji and Braeburn). The colour development in Fuji apples is considerably slower, with a much larger variation in stage of development. The location in the canopy affects all aspects of biological variation (biological shift factor and asymptotic starting level of colouration) for all three colour aspects L*, a* and b*, but only the mean value, not the standard deviation. The biological shift factors per colour aspects are linearly related. Once induced, variation remains constant during development.

Promotion of flowering by Mn-EDDHA in the long-short-day plant Wolffia arrhiza (L.) Horkel ex Wimm

Summary Investigations were made into axenically cultured long-short-day (LD-SD) plants Wolffia arrhiza, grown under 16 h LD and 8 h SD conditions and light intensity of 48 μmol · m−2 · s−1. The experiments were aimed at establishing the effects of GA3, EDDHA, and Mn-EDDHA, as well as their combinations on flowering. In the used concentrations under LD conditions, flowering was induced by GA3 (0.1−0.7 μmol · L−1) and by EDDHA (of 1.5–21 μmol · L−1). GA3 in higher concentrations (1.4–2.9 μmol · L−1) did not induce flowering. In the nutrient solution with Mn-EDDHA (1.5 μmol · L−1) flowering was promoted significandy under LD and SD conditions when compared with flowering in the same nutrient solution with an equivalent amount of manganese in the nonchelate form 1.5 μmol · L−1 MnCl2. Flowering was promoted to the greatest extent under LD conditions in the nutrient solution with Mn-EDDHA and the addition of combinations of = optimal concentrations of GA3 (0.4μmol · L−1) and EDDHA (19.5μmol · L−1). The obtained results also show that GA3, EDDHA and Mn-EDDHA may replace the SD requirement for flowering in the examined plants.

The computer-aided teaching of apple tree pruning and training

Fruit growers have to master tree training and pruning to achieve high yields, but learning these skills is time consuming. A special tree training and pruning teaching application EduAPPLE has been developed, but before including it in the higher education, we tested, if benefits of EduAPPLE use can be observed.

Impact of various types of anti-hail nets on light exposure in orchards and quality parameters of apples : a review

Abstract The new Common Agricultural Policy (CAP) has been designed to shrink funds that Hungarian agricultural reform will in Nowadays, anti-hail nets are a part of basic equipment in a modern apple orchards. They decrease the risks of apple production and thus allow regular and quality apple harvest. Colours of nets differently obstruct the passing of light through the net, which directly affects some quality parameters of the yield, especially the fruit skin colour. The article includes a brief overview of studies associated with the impact of light exposure under different types of anti-hail nets on quality of apple fruits, as well as investigations which deal with adaptation of various technological measures, such as the use of reflective ground foil. A part of data from the existing literature explains the effect of anti-hail net usage on forming a microclimate under the net, and consequently, its effect on the development and dynamics of diseases and pests.

Apple Variety Assessment with Analytical Hierarchy Process

Selection of a proper cultivar is one of the most important management decisions when investing into apple orchard. This paper presents a methodology for evaluation of suitability for cultivation of some apple cultivars by using a multi-criteria model based on analytical hierarchy process. The software tool Expert Choice was used to support growers in making decisions about which new apple cultivar to grow. The model was applied to 13 cultivars with data derived from questionnaires completed by group of experts of different fields (orchardists, experts for fruit production economics and fruit marketing, cultivar breeders, experts of state service and commission for introduction of new cultivars, experts for fruit storage and fruit quality assessment, plant protection and fruit growing advisers). The results are shown as priority for individual cultivar. The potential of the model for assessing apple cultivar is demonstrated with the aim of providing a comprehensive explanation and justification of the assessment technique. It also indicates strong and weak points (in market potential, fruit estimation, production demands and tree estimation) of each assessed cultivar.ZusammenfassungBei der Ausgestaltung und betrieblichen Planung von Geschäftsalternativen in der Betriebswirtschaftslehre gewinnt die multikriterielle Bewertung immer stärker an Bedeutung. Der vorliegende Beitrag erörtert, wie verschiedene Kriterien bei der Apfelsortenbewertung gemeinsam berücksichtig werden können. Sortenauswahl bei der Neupflanzung einer Apfelanlage ist eine der wichtigsten Entscheidungen in der Obstbaubetriebswirtschaft. In diesem Artikel wird die Sortenauswahl mit der Anwendung der multikriteriellen Methode, basierend auf dem analytischen Hierarchieprozess, dargestellt. Die Methode wurde durch Expert Choice Software implementiert. Das Modell wurde an 13 Apfelsorten angewandt. Dabei wurden 17 verschiedene Expertenmeinungen in eine einzige Wertung aggregiert.