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Mészáros M., Kosina J., LaňarL., Náměstek J. (2015): Long-term evaluation of growth and yield of Stanley and Cacanska lepotica plum cultivars on selected rootstocks. Hort. Sci. (Prague), 42: 22-28.During 1992-2012, trunk cross-section area (TCSA), cumulative yield, yield efficiency and suckering of plum cultivars Stanley and Cacanska lepotica in combinations with vegetative rootstocks Myrobalan SE 4043, Myrobalan SE 4044, MY-KL-A, GF 655/2, GF 43, Damas C SE 4045, Pixy, St. Julien A and generative rootstock Myrobalan seedling were evaluated. The results indicated significant differencies of the characteristics between the evaluated cultivar/rootstock combinations for each cultivar. The long-term experience indicates that the evaluated characteristics of the trees on different rootstocks can significantly change during the ontogenetical developement in the orchard. This is demonstrated by the difference in the entering into the bearing stage, different abudance of the yields, the time of reaching of maximum yields and also in changes of growth intensity. For detailed description of the rootstock characteristics long-term trials are required. For cv. Stanley, Myrobalan SE 4043 is the best rootstock for long-term orchards and St. Julien A for orchards with a higher replanting rate. For cv. Cacanska lepotica, Myrobalan SE 4043 seems to be the best rootstock.Keywords: ontogenesis; stage; productivity; TCSA; bearing; suckering Plum is one of the traditional fruit crops grown in the Czech Republic. For good performance in the orchards, the rootstock has an important influence on the scion cultivar. The most frequently used rootstock in Czech Republic is still the myrobalan seedling. With the increased need for intensification of fruit production, several rootstock trials have already been established and evaluated in central Europe (Hrotkó et al. 1998;Kosina 1998Kosina , 2007Sosna 2002;Sitarek et al. 2007) in order to find more productive scion-rootstock combinations. Authors in these publications presented results of the influence of new rootstocks, described by Hrotkó et al. (1998), Jakob (1992, Hartmann (1995), andWebster (1997), on selected plum cultivars, nevertheless most of them are results from young orchards, which just enter the productive stage. It is interesting to supplement this information with long-term results.Experience from international rootstock trials shows that the performance of a rootstock in combination with the cultivar may change in different agroclimatic conditions (Hartmann et al. 2007). That is the main reason to test the same rootstocks in different regions of Europe and of the world. However, the question is, if the rootstock with the cultivar retains qualities in growth and bearing throughout the ontogeny

During 1999–2016, the performance of ‘Red Bartlett’, ‘Conference’ and ‘Beurré Alexander Lucas’ grafted on four pear (Pyrus) rootstocks OH × F 69, OH × F 87, OH × F 230, OH × F 333 and on quince (Cydonia) rootstock BA 29 was evaluated at the RBIP Holovousy Ltd. For each combination, trunk cross-section area, cumulative yield, yield efficiency and mean fruit weight were assessed. The growth vigour of the scion cultivars on OH × F rootstocks was similar or slightly higher comparing to the growth on BA 29. Throughout the years, the growth vigor and productivity of the rootstock combinations may change. Less vigorous combinations of rootstock/scion were linked with higher yields in young trees, but usually with just moderate yields in later seasons. By contrast, combinations with higher growth vigour had usually higher yields in the later seasons. This balance is genotype specific, where aside of rootstock an important role is played by the scion cultivar vigour. The bearing precocity may be influenced by the cultivar as well. The results can vary with different climatic conditions and orchard management.

Two growing systems were compared – slender spindle and modified slender spindle, supplemented with or without additional summer pruning. The trial was carried out in orchard of the apple variety ‘Topaz’ in years 2012–2014. The assessed parameters were: trunk cross sectional area (TCSA), crown volume, number of cuts, dry matter weight of pruned wood, cumulative yield, yield efficiency, and relative occurrence of size classes of fruits. The objective was to confirm the hypothesized advantages of modified slender spindle in the period of increasing yields. Based on statistical analysis there was no significant difference among systems in growth measured by TCSA. Increase in crown cubage was the highest on slender spindle with additional summer pruning. The lowest increase of crown cubage was on modified spindle without summer pruning. Number of winter cuts and similarly dry weight was significantly higher on the modified spindle only in 2013. Additional summer pruning influenced both the above-mentioned parameters. There were no significant differences in cumulative yield and yield efficiency between systems. Similarly, the difference in the occurrence of various fruit size classes was not significant. We conclude that study needs to be extended in order to confirm the suggested trends.

Diagnostic of the nutritional status in fruit trees can be estimated using different models. However, these models usually do not fully match the character of the perennial crops and their accuracy needs to be improved. This study aimed at deepening the understanding of the aspects controlling mineral content of macro- and micronutrients and fruit quality of the apple trees with respect to the crop load and vegetative shoot growth. The focus was given on description of the nutrient content variability in time and space, its relation to important physiological events, and conditions altering their gradient in leaf and fruit. The evaluation was carried out with six years old 'Golden Delicious' apple trees on M9, planted in an experimental orchard. Flowering rate, total yield, shoot growth intensity, mean fruit weight and quality along with mineral content of leaves, and fruit in different development stages were analysed according to intensity of natural or regulated flowering and fruit set, respectively. We found that aside of macroelements, iron, and manganese depended on the crop load. For nitrogen, phosphorus, and potassium content, their gradient increased up to 10–25% within the sufficiency range as the trees tried to maintain certain level of these nutrients in leaves and fruit simultaneously during deficit. In contrary, the higher content of Mg, Fe, and Mn related to the avoidance of deficit through up to 20–30% higher uptake in trees with higher crop load. Phosphorus, potassium, and calcium content in short fruiting shoots was more stage dependent, showing relation with the timing of cessation of particular meristematic growth activity. If no intense deficit occurred, the trees kept unrestricted initial investment of nutrients in the fruit during cell division stage whatever the crop load was. Their content at the later development stages appeared to be more dependent upon the consumption by particular sink. These findings allowed to improve the interpretation of the fruit trees nutrition status due to adaptation of the reference nutrient content in low cropping trees by a reduction of 5–10% N and P, 10–15% Ca, as well as by an increase of 15–20% K content in leaves at the stage with fruit size of 20 mm, and without change in P content at the stage of about 70% of final fruit size.

• Excess vegetative growth and irregular fruit-bearing are often undesirable in horticultural practice. However, the biological mechanisms underlying these traits in fruit trees are not fully understood. Here, we tested if growth vigour and susceptibility of apple and pear trees to alternate fruit-bearing are associated with vascular anatomy. • We examined anatomical traits related to water transport and nutrient storage in young woody shoots and roots of 15 different scion/rootstock cultivars of apple and pear trees. In addition, soil and leaf water potentials were measured across a drought period. • We found a positive correlation between the mean vessel diameter of roots and the annual shoot length. Vigorously growing trees also maintained less negative midday leaf water potential during drought. Furthermore, we observed a close negative correlation between the proportions of total parenchyma in the shoots and the alternate bearing index. • Based on anatomical proxies, our results suggest that xylem transport efficiency of rootstocks is linked to growth vigour of both apple and pear trees, while limited carbohydrate storage capacity of scions may be associated with increased susceptibility to alternate bearing. These findings can be useful for the breeding of new cultivars of commercially important fruit trees.

The research was focused on the comparison of two pruning methods (winter pruning and winter + summer pruning) applied to apple trees trained to a standard and a modified slender spindle. The orchard of 'Topaz' trees, grafted on rootstock M 9, was planted in spring 2011. In the years 2013 -2016, trunk cross sectional area (TCSA), crown volume, cumulative yields, yield efficiency, relative proportion of fruit size classes, number of cuts and dry matter of pruned wood were analyzed. The total growth intensity of the trees, measured by TCSA, was similar among the treatments. The trees of modified slender spindle had lower mean crown volume (2.751 -2.765 m 3 ) comparing to slender spindle with additional summer pruning (3.355 m 3 ) and proved to better control the tree size. The modified slender spindle brought similar or slightly lower cumulative yields, but significantly higher proportion of good sized fruits (in categories above ø 70 mm) comparing to slender spindle. The pruning of modified spindle brings generally higher number of cuts removing a higher amount of woody biomass in comparison to slender spindle, regardless if combined with summer pruning. The additional summer pruning brought no beneficial effect in reduction of growth, fruit production and fruit size of the modified slender spindle.