Morphological characteristics of chestnut Castanea sativa from the area of Una-Sana Canton
Una-Sana Canton (USC) has a large forest areas where chestnut Castanea sativa Mill. grows as a self-sprout tree. The aim of this paper was to determine the morphological characteristics of chestnut fruits from four self-sprout locations (Bužim, Bosanska Krupa, Cazin and Velika Kladusa), and plantation where the domestic tree is grafted with Italian Marroni. Number of fruits/kg, the useless fruit, the percentage of kernel, diameter, width, height and weight of fruits were determined. The number of fruit/kg ranged from 160-222.5, percentage of useless fruit varied between 0.88-6.7%. Percentage of kernel ranged from 78.5 to 87.3%. According to the diameter classification, width, height and weight of fruits, chestnuts fruit from USC enters the category of the smallest fruits of the Mediterranean area. Statistical significant differences (p≤0.01) in the number of fruits/kg and weight of fruits was found between locations, as well in the width of the fruit (p≤0.05), while there is no difference in the diameter and height of the fruit. For grafted chestnut, all the characteristics provided better quality.
Phenotypic and Genotypic Diversity of European Chestnut (Castanea sativa Mill.) in Slovenia – Opportunity for Genetic Improvement
Phenotypic diversity of 244 chestnut trees was investigated. They originate from the Mediterranean and from two continental regions in Slovenia. In 3 years of analyses, length, diameter, thickness and weight of fruits; length and width of hilum, the pellicle intrusion; shape and colour of fruits; and the embryony were dealt with. The continental trees have smaller fruits than the Mediterranean trees; their fruits show greater variability in shape and the pellicle intrusion is stronger. They also exhibit polyembriony more frequently and they rarely have darker stripes. The sample of 46 trees from all three regions was used for the comparison between the phenotypic and genotypic diversity which had been investigated by RAPD analysis. In both cases, the UPGMA method was used for the classification of the trees into groups. Six pomological clusters were established. The clusters I, II, III and V comprise only the trees from the continental part. The cluster IV comprises nine trees of the marron type from the Mediterranean and one KOZ1 tree with equal pomological characteristics but originating from the continental part. The cluster VI is composed of eight trees from the continental part and one RAV3 tree whose fruits are very small and it originates from the Mediterranean. The Jaccard’s coefficient of similarity is used in order to evaluate genetic relations. On the RAPD dendrogram four clusters of trees are defined. The continental trees are divided into three clusters and exhibit greater genotypic diversity than the Mediterranean trees which form only one cluster. With the RAPD analyses the differentiation of the trees with regard to their pomological traits is determined in 60–90% of the cases. The outcome of the research point to the fact that the Slovene chestnut is a rich source of genetic diversity and is very suitable for further breeding purposes.
Effects of Severity of Renovation Pruning on Tree Growth and Nut Yield and Size in Chestnut Tree (Castanea crenata Sieb, et Zucc.)
1. Effects of severity (heavy, medium and light) of renovation pruning on improving the yield and the quality (size) of the nut in low-yield or senescent chestnut trees were examined. 2. Heavy pruning resulted in causing vigorous top growth, which was maintained for a longer period of time. Light pruning could increase tree vigour for only a short period of time, but its effect disappeared in the third year. In this case, however, the tree vigour was recovered by trying it again in the fourth and fifth year. 3. Removal of most of the primary or secondary scaffold branches stimulated the growth of shoots on the remaining scaffold branches in the same tree, as compared with that of a few of them. 4. The heavy pruning resulted in greater 'leaf-area index' and 'leaf-area density', and also much greater 'leaf-wood' and 'leaf-sapwood' ratios than the medium or light pruning. 5. The yield per tree was reduced by the pruning in the first year, but it increased markedly in propotion to the severity of pruning after the third year. Therefore, the cumulative yields per tree in five years were in the following order heavy>medium>light pruning. Yearly changes of the yield per ground area occupied by a tree showed almost identical trends with those of the yield per tree. 6. Nut size increased with the severity of pruning. This effect did not disappear for five years in the heavily-pruned tree. Whereas, it disappeared in the third year in the lightly-pruned tree. In this case, the nut size increased again by another renovation prunings in the fourth and fifth year. 7. To improve the nut yield and quality in low-yield or senescent chestnut trees, therefore all their scaffold branches should be renovated at the same time or over the consecutive several years.