simultaneously grafted softwood cuttings of rootstocks for apricots

International Conference of „Perspectives in European Fruit Growing“ on Horticulture Faculty in Lednice 2006then put into plant pots with a mixture of peat and pure sand. The plant pots were placed in a shaded greenhousewith high humidity.The plants were subsequently assessed on the basis of which of the cuttings had successfully rooted andwhich of the scions were living i.e. had green buds and leaves.RESULTS AND DISCUSSIONThe highest percentage survival was seen in the combination PS-1/Harcot, at 100 % (Table 1), andthe variety Harcot also had the most vigorous growth. A commercially viable grafting success rate was seen in thecombinations VVA-1/Harcot (61.7 %) and AP-1/Velkopavlovická (73,3 %), while a marginal success rate was seenin the combination AP-1/Harcot (47 %). The worst results were for the combinations M-LE-1/Velkopavlovická, PS-1/Velkopavlovická and PS-1/Héléne du Roussillon.The most successful grafts were seen in the rootstock ´AP-1´ (44%), then ´PS-1´ (39 %) and ´VVA-1´ (34%). The variety with the highest grafting success rate was ´Harcot´ (48,6 %). Statistical analysis using the Student-Newman-Keuls test, software Unistat 5.1, found significant differences between the combinations of rootstocks andvarieties, and between the varieties. No statistically significant differences were found between the rooting abilitiesof the rootstocks.An interesting result was the relatively low survival rate for scions of the variety ´Velkopavlovická´,especially in combination with the apricot seedling ´M-LE-1´. It is also interesting that the combination of ´Harcot´on peach rootstock PS-1 had considerably the highest survival percentage. According to KOLESNIKOV, (1964), itis difficult to successfully make grafts between different species of fruit, such as peach and almond or peach andapricot, and some varieties of pear and quince, which tend to break at the point of the graft even though callusformation is good. The best results are always achieved by grafts between members of the same species.In addition to the poor affinity of rootstocks and scions, another problem of this particular method ofpropagation could be the growing environment itself. Cold and rainy weather, with low light levels, could negativelyaffect rooting in years such as 2006. BILLING, (1990) described suitable air temperatures in the rootingenvironment as ranging from 20° to 25 °C, and although bottom heating to 20 °C is not strictly necessary it mayimprove the rooting of softwood cuttings.Winter survival can be a problem when taking softwood cuttings to propagate many difficult to root Prunusspecies and hybrids. These can take several months to root and are then very difficult to transplant and subsequentlyestablish (TROMP et al., 2005). The problems of overwintering grafted softwood cuttings will have to beinvestigated in the next few years.WEBSTER, (1995) describes successful methods of shortening the juvenile phase by 1-2 years in appletrees (MM.106/Cooper 7SB2), plum trees (Myrobalan B/Burmosa plum) and pear trees (Quince A/ Conference,Williams, Bon Chretien). Grafted hardwood cuttings were taken in November using a portable Omega machine andplanted directly in the field or nursery. TETSUMURA et al., (2003) experimented with grafting softwood andhardwood cuttings using persimmon, where the softwood cuttings rooted better than the hardwood cuttings and thegrafted cuttings rooted even better than the non-grafted cuttings (success rates ranged from 13 % to 33 %).CONCLUSIONThe experiment showed that the technique of simultaneously taking cuttings and making grafts is arelatively good method for shortening the juvenile phase in fruit trees. The most difficult part of the process isproviding the right growing conditions in the propagating greenhouse. The effect of rootstock on graft compatibiltyis not statistically significant. However, it is too early to say how useful this method will be compared to classicalmethods.AcknowledgmentsThis research was carried out with the support of grant number QF 3221 from the National Agency forAgricultural Research, Ministry of Agriculture, Czech Republic.REFERENCESAldwinckle, H. S., 1975. Flowering of apple seedlings 16-20 months after germination. HortScience 10: 124-126;Billing, H. O, 1990. Rapid production of apple rootstocks by softwood cutings. Sci. Hort. 42: 277-287.Couranjou, J., 1977. Variétés d’abricotiers. Invuflec, Paris.Hackett, W. P. 1985. Juvenility, maturation and rejuvenation in woody plants. Hort. Rev 7: 103-155.Hansche, P. E., Beres, W., 1980. Genetic remodelling of fruit and nut trees to faciliate cultivar improvement.HortScience 15: 710-715.Jackson, J. E. 2003. Biology of apples and pears. Cambridge University Press: 73-77, ISBN 0521380189.Kolesnikov, V., 1964/2002. Fruit biology. University Press of the Pacific Honolulu, Hawai, ISBN 1-4102-0201-1.Langilier, P., Fournioux, J. C., 2000. Endogenous abscisic acid in juvenile and adult grape (Vitis vinifera L. Cv.Pinot noir). Vitis 39: 47-48.Lewandowski, M., Zurawicz, E., 2000. Shortening the juvenile period in apple seedlings by grafting on p22dwarfing rootstock. 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