Earlier studies concerning self-, free- and cross- fertilization of apricot varieties grown in Hungary, proved the existence of self-sterile as well as self-fertile varieties within the recommended assortment. The self-sterile and partially self-fertile varieties should be planted in association with polliniser varieties, only. The present pape...r reports about the yields of trees of the widely grown, self-sterile local variety, Ceglédi óriás (Giant of Cegléd), depending on the distance of adequate polliniser trees. In the univarietal, 27 row-wide block of the relevant variety, an efficient polliniser, Magyar kajszi was planted to the 10th and 19th row. In the close vicinity, another block of polliniser, Rózsakajszi C. 320 was located. The number of fruits set per tree has been counted or estimated in two consecutive years. In both seasons, the yield of the Ceglédi óriás trees diminished with the growing distance from the nearest polliniser trees. Those trees in the center of the block, between the two (10th and 19th) rows of Magyar kajszi bore acceptable yield (40 kg/tree in 1987), however, considerable reduction of the number of the fruits set was stated already in the 4-5th row from the polliniser away. Similar gradient of fruit set was apparent in relation to the neighbouring block of Rózsakajszi C 320. The beneficial effect of the vicinity of polliniser varieties was obvious as far as the distance of the 10th row. Taking into consideration the self-sterility, the early blooming time and the poor fertilization of the variety Ceglédi óriás, a planting design of associating it with at least two polliniser varieties (e.g. Gönci magyar kajszi and Ceglédi bíbor) is highly recommended. On the basis also of earlier results, a proposal has been developed for the association of apricot varieties as recommendations for optimising yields. Blooming time, fertilizing potential, schedule of the picking season and market possibilities have to be considered simultaneously.
The flowering phenology, blooming time and inter-fertility relations of 63 European plum varieties has been studied at growing sites with different ecological conditions during a 10 year long period. The purpose was to develop a system of variety combinations which approaches an optimum in fertility as long as inter-fertility relations will cea...se to be a limiting factor of yield. According to their blooming time, varieties are assigned to 5 groups: very early, early, medium, late and very late. As for their fertility relations, four groups are formed: self-sterile (0%), partially self-fertile (0.1 to 10 %), self-fertile (10.1 to 20 %) and highly self-fertile (more than 20 % fruit set with self pollination). The four categories of fruit set at free pollination are also relevant to the grower: low (less than 10 %), medium (10 to 20 %), high (20 to 40 %) and very high (more than 40 % fruit set).
By artificial cross pollination, one combination Cacanska najbolja x Stanley proved to be mutually inter-incompatible. Blocks planted to a single self-sterile variety flanking a pollinizer variety proved the spacial distribution of the pollen. The reduction in fruit set was already apparent in the second row away from the pollinizer trees. In a large plantation, without bee hives, relatively low yield was stated on self-sterile trees even close to the pollinizer.
In the case of self-sterile and partially self-fertile varieties, a combination of three varieties is recommended. The blooming period of the pollinizer variety should overlap the period of the self-sterile variety at least by 70 %, and the distance should not exceed 15 to 20 meters. Association of self-fertile varieties may also enhance the productivity of the trees. In that case an overlap of 50 % in blooming time and a maximum distance between the varieties of 30 to 40 meters will be sufficient.
In commercial fruit tree orchards, consistently high yields are necessary for a durable economy. The Swedish pear cultivar 'Carola' has been noted for low setting in some orchards, possibly due to insufficient pollination. In this study, fruit set was evaluated in a research orchard where `Carola' had been planted together with four potential p...ollinators. Total yield and number of fruits was noted during three and four years, respectively. In 2003, seeds were germinated from the harvested `Carola' fruits, and the paternity of three seedlings from 50 trees was determined with RAPD analysis. 'Clapp's Favourite' had sired 39.6% of the seedlings, closely followed by `Seigneur d'Esperen' (30.7%) and 'Clara Frijs' (26.7%) whereas 'Skanskt sockerparon' only sired 1.1% of the seedlings. The remaining 2.3% appeared to have been derived by selfing. Pollen-limited seed set was indicated at surprisingly short distances; accumulated number of fruits on the `Carola' trees was significantly higher when separated by only 2 m from one of the two most efficient pollinators, 'Clapp's Favourite' or 'Seigneur d'Esperen‘, compared to trees 4—l0 in away in the same row. Number of viable seeds per fruit was also higher in fruits from trees immediately adjacent to the pollinators, suggesting an effect of improved pollination success. The importance of very short inter-cultivar distances for efficient pollen transfer became even more clear when comparisons involved the true pollination distances as determined by RAPD; the accumulated yields decreased linearly from 55 kg at a 2 in distance to only 17 kg at 13 m.
During 2000 and 2007, rootstocks of different vigor have been tested in a high density sweet cherry orchard with 'Vera '® and 'Axel'® cultivars at 4 x 2 meter row and plant distance. Trees are trained to Hungarian Spindle with permanent basal branches; in the alley way naturally grown grass is managed by mowing. The first considerable fruitin...g was in 2004. Every year we measured trunk and canopy parameters of the trees, productivity and fruit size. Our conclusion is that the rootstocks considerably affected the growth, precocity, as well as tree and orchard productivity, fruit weight of sweet cherry cultivars, but these rootstock effects are modified by cultivars, except for growth vigor. According to our results Cema, SL 64, and Bogdany are vigorous rootstocks, moderate vigorous are MaxMa 97, Pi-Ku I , and Tabel® Edabriz, Gisela® 5 and Prob are dwarfing rootstocks. Besides the precocious Gisela® 5 also mahaleb rootstocks CEMA, Bogdany and SL 64 showed considerable precocity, which can be explained by the larger bearing surface to the time of turning to bearing, and a similar or relative large density of burse shoots on fruiting branches. Cumulative yield of 'Axel'® was the highest on Bogdany and on Cerna, contrary to Gisela® 5, which produced only 50% of the previous ones. Cumulative yield of 'Vera'® was the highest on SL 64, and no significant difference was found, compared to trees on rootstocks Cema, Bogdany and Pi-Ku I . Cumulative yield production of trees was smaller on Gisela® 5, Prob, Max Ma 97 and Tabel® Edabriz rootstocks. Corresponding to the literature data of yield efficiency calculated on TCSA basis was highest on Gisela® 5 rootstock. but the efficiency calculated on canopy volume of 'Axel•® trees was similarly high on CEMA and Bogdany, and that of 'Vera'® trees relatively high on CEMA, Bogdany, SL 64 and PiKu I rootstocks. When calculating orchard efficiency al spacing 4 x 2 meters (1250 tree/ha), we received highest yield values on Bogdany, CEMA, SL 64, and PiKu I rootstocks, with large fruit weight. Rootstocks also affect fruit weight. We measured the largest fruit weight on trees on Bogdany.