DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 1-2/1995 str. 27 <-- 27 --> PDF |
F. Mrva: MODEL OPLEMENJIVANJA OBIČNOG ORAHA (JUGLANS REGIA L.)... Šumarski list br. 1-2, CIX (1995), 15-26 SUMMARY: The vhole fund of walnut trees in Croatia is almost entirely of generative origin and also almost completely in private property. The main character of its cultivation is an extensive fruiter manner, without any agricultural application. Fruit growing and forest practice has remained modestly in the propagation of commercial varieties, by which ecological adaptability in different conditions was not examined. Adapted populations offer the possibility of qualitative tree selection with regard to growth, resistance to diseases and insects and also to frost and low temperatures and good fruits produce. This paper present a review of results obtained on selection, vegetative propagation by grafting and generative propagation. Initial grafting of selected trees and first results of graft survival (19%), which have been gradually improved (to 57%), showed that with the use of primary scions, which are mostly of unequal quality, it was very difficult to propagate a larger number of grafts. For this reason it was necessary to start with the founding of a clonal bank for production qualitative scions. In the period 1979—1983, 270 grafts of 27 different clones were propagated and transplanted in a clonal bank. From these grafts the secondary scions were taken and the propagation was continued up to 1990 and was interrupted in 1991. with the beginning of the war in Croatia. A total of 1500 grafts were produced for establishment of the first clonal plantations and their testing on different sites. The grafted material for almost four years has been inaccessible and the great effort is now uncertain. A tree breeding model was developed including the primary selection of desirable trees from adapted population and also secondary selection in half-sib progeny tests. In this study some results were presented relating to water soaking of nuts (48 hours) at room temperature with a very good average result of germination in soil — 67,9%, for 18 selected tree samples (Table 1, Graphs 1 and 2). This result would have been better, but samples of three selected trees with the big nuts (Graph 1) significantly lowered the average. The diameter and height growth analysis of plants in the first established half-sib progeny test showed differences in mean values between progenies (Table 2, Graphs 3 and 4). In general growth was not successful. The two progenies selected from late flushing trees grew weaker than other progenies. Results of flushing phenology performed at the nursery stage of the progeny test showed small diferences in phenophases in 13 progenies, while in the two late flushing progenies differences were larger. Results are tabulated and graphically presented. |