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Crop Load, Fruit Thinning and their Effects on Fruit Quality of Apple (Malus domestica Borkh.)
29-35Views:309Crop load, a quantitative parameter used by industry, is generally defined as the number of fruit per tree. It is often expressed in terms of number of fruit per trunk cross-sectional area (fruit/TCSA). Crop load is the most important of all factors that influence fruit size, and the removing of a part of the crop is the most effective way to improve fruit size.
The potential size of a given pome fruit is determined early in the season and growth proceeds at a relatively uniform rate thereafter. This uniform growth rate permits the accurate prediction of the harvest size of the fruit as early as mid-summer. The growth rate, once established, is not easily altered, and fruit numbers, therefore, can affect fruit size only within definite limits and maximum effectiveness requires adjustment in fruit numbers relatively early in the season. It was established, that „thinning does not change a potentially small fruit into a large fruit, but rather insures that a potentially large fruit will size properly.” Emphasis should be on estimating fruit numbers rather than fruit size.
Fruit thinning can quickly reach the point of diminishing returns. Rather than a high percentage of large fruits, the objectives of thinning should be the elimination of the smallest fruits, improved fruit quality and annual production. Fruit thinning is accomplished by hand or chemical thinning. Chemical thinners are separated into categories as bloom thinners and post-bloom thinners. Early removal of potential fruit (blossom thinning) is currently used in many apple producing areas to enhance flower initiation for next year’s crop and thus, return bloom. It also results in reduced competition for photosynthates. Blossom thinners usually have a caustic effect on floral parts.
The amount of fruit left on a tree should be determined by the vigor and general condition of the tree. Leaf area per fruit affects the number of spurs flowering the following season. It can be difficult to separate timing and fruit number effects in crop loading studies, as abscission rates after hand thinning of retained flowers/fruitlets tend to very with the time of hand thinning. -
Contexts between apple orchards with various cultivar comparisons and the effect of ATS (ammoniumthiosulphate) on fruit thinning
35-38Views:143Our research focuses on a fruit thinning material that can also be used in apple production. This material reduces significantly the required manual labor of hand thinning by russeting the blossoms selectively. The ATS (ammonium-thiosulphate) acts as chemical desiccant contrary to the nowadays commonly used materials such as naphthalene acetic acid, naphthyl acetamide, benziladenin and ethylene, which affect the metabolic processes of the plant by regulating the hormone system. In our experimentals cultivar ’Pinova’ and ’Golden Reinders’ were treated with different concentrations of ATS. The effect of these doses on the fruit setting and the quality and quantity parameters of the fruits was studied. According to our results, in the case of cultivar ’Pinova’ the ATS did not have any detected effects at the concentration of 1.5%. Application of ATS at 3% decreased considerably the fruit setting and fruit yield, accordingly the mean fruit size improved. The response to treatment in the case cultivar ‘Golden Reinders’ does not have any similar consistent results.
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Productivity of thinned black locust (Robinia pseudoacacia L.) stands in Hungary: case studies
181-186Views:107Black locust (Robinia pseudoacacia L.) is one of the most important introduced tree species in Hungary, covering more than 24% of the stocked area and providing approximately 20% of the country’s annual timber cut. Consequently, the research and development activities related to the improvement of the growing technology of black locust are also important, especially in mitigating the negative effects of climate change. The aim of this study was to quantify growth and yield, responses of even-aged 12–31–year–old black locust stand to thinning in Hungary. The study has proved that irrespective of the yield class, age and thinning intensity, thinning could not increase effectively the cumulative volume production. As percentage of the control it has changed between +0.6 and -8.4%. On the other hand, it could increase the stand value based on stem quality index by 10–21%.
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Leaf and root evaluation of bioactive compounds of different beetroot varieties
135-139Views:201The importance of beetroot lies in the numerous health benefits, attributed to its wide-ranging array of minerals, vitamins and bioactive compounds which play a key role in the human diet. Generally, beetroot is consumed for its root, however, its leaves also contain a good amount of bioactive compounds. The experiment was carried out with four beetroot varieties in order to compare the amount of bioactive compounds in the root and the leaf. The analyzed data were total dry matter content, total polyphenol, flavonoid and vitamin C.Results have shown that roots contain the highest amount of bioactive compounds. Nevertheless, leaves can be also considered a significant source. Therefore, consumption of the young leaves is highly recommended due to their availability after thinning or at maturity stage (60 days after the germination). Of the examined varieties, ‘Libero’ demonstrated the highest total polyphenol, flavonoid and vitamin C values, although it was found to be statistically insignificant. -
The effects of tending cuttings on yield and value changes in black locust (Robinia pseudoacacia L.) stands: a case study
111-113Views:91Thinning experiments in black locust (Robinia pseudoacacia L.) stands have been carried out for many years in Hungary. This species has great economic importance in the timber supply of the country. This paper evaluates the effects of tending cuttings in two aspects: the effect on yield and stand value. The case study has proved that in black locust stands tending cuttings can not increase the periodic total production but the stem-quality index can be increased by 2%.
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Yield and crown structure characteristics in a red oak (Quercus rubra L.) stand: Case study
49-53Views:118The paper provides the results of a detailed analysis of timber volume and several important crown variables of red oak (Quercus rubra L.) based on an experimental plot in eastern Hungary. At the age 32 years the crop trees belonged to different height classes. If the volume of the mean tree from height class I was considered as 100%, the volume of the mean tree of class II was 59%, and the mean tree of class III was only 36%. It appeared that there was a significant correlation between crown indices and yield. For this reason, diameter at breast height showed a positive linear correlation with crown diameter (R2= 0.6211). Additionally, there was also positive linear relationship between crown diameter and volume (R2= 0.6908). The variation of crown indices is height even within the same stand and indicates the importance of following a selective thinning operation method.