The promising branching agent cyclanilide [1-(2,4-dichlorophenylaminocarbonyl)-cyclopropane carboxylic acid] is not permitted in the EU and the low vigour rootstocks preferred by growers make the branching of young sweet cherry (Prunus avium) trees difficult in the temperate zone production regions. To increase the number and length of new branches (“feathers”) on such trees, chemical (6-benzyladenine [BA], gibberellic acid [GA_4/7]), mechanical (leaf pinching, summer notching) and various combined treatments were tested from 2015–2018. The numbers of feathers divided into three different lengths (1–10 cm, 10–30 cm and > 30 cm) were assessed as the main indicator of quality, supplemented with other morphological characteristics. Summer notching induced an insufficient number of feathers and led to some negative effects on the trees. The number of feathers from BA or BA with GA_4/7 treatment also was insufficient. The effect of pinching alone was variable. The number of all feathers generally was highest when pinching was combined with BA, regardless of the year or cultivar.

Chemical (benzyladenine -BA, gibberelins -GA 4/7 ), mechanical (leaf pinching), and combined treatments were tested in 2015 and 2016 to increase the number and length of sylleptic side shoots (feathers) on apple (´Rubinola´, ´Topaz´/M9) and plum (´Elena´, ´Tophit´/St. J. A) trees. The numbers of feathers of three different lengths (1-10, 10-30, and >30 cm) were measured as the main indicator of quality along with other important morphological characteristics. The numbers of all feathers on both apple cultivars were the highest when BA was applied four times. However, mainly an increase in the numbers of shorter feathers was observed in both years. The efficiency of leaf pinching of apple trees was low. The numbers of all feathers and feathers 1-10 and 10-30 cm in length were the highest in both plum cultivars when BA was applied four times in both years. In contrast to apples, the induction of feathers longer than 30 cm improved in plum cultivars when pinching was used. Thus this approach can be also effective in organic production. ABSTRAKTV letech 2015 a 2016 byla testována chemická (6-benzyladenin -BA, gibereliny -GA 4/7 ) a mechanická (seštipování listů) ošetření a jejich kombinace pro zvýšení počtu a délky bočních syleptických výhonů (obrostu) jabloní (´Rubinola´, ´Topaz´/M9) a slivoní (´Elena´, ´Tophit´/St. J. A). Hlavním indikátorem kvality výpěstků byl počet výhonů tří různých délek (1-10, 10-30 a >30 cm) spolu s dalšími důležitými měřenými morfologickými charakteristikami. Obě jabloňové odrůdy měly nejvyšší počet výhonů při čtyřikrát opakovaném ošetření BA, ale vliv byl v obou letech zaznamenán pouze na zvýšení počtu kratších výhonů. Seštipování listů mělo u jabloní malou efektivitu. Obě slivoňové odrůdy měly nejvyšší celkový počet výhonů a počty výhonů délky 1-10 cm a 10-30 cm také při čtyřikrát opakovaném ošetření BA v obou letech. Na rozdíl od jabloní byl ale počet výhonů délky nad 30 cm u slivoní nejvíce podpořen v případě provedení samotného seštipování. Proto by seštipování mohlo být efektivně využíváno i v ekologické produkci.

The research was conducted in the fruit nursery of the Research and Breeding Institute of Pomology (RBIP) Holovousy, Czech Republic in 2015, 2016 and 2017. The efficacy and potential phytotoxic effect of soil herbicides were assessed in spring‑planted and summer‑budded rootstocks M9, MA, Gisela 5 and St. Julien A in seven treatments with the following herbicides: linuron, metazachlor, metamitron, chlorotoluron, dimethenamid‑P, pendimethalin, and combination of pendimethalin and dimethenamid‑P in one product. The effects of the surfactant and simulated rainfall in combination with the pendimethalin + dimethenamid‑P treatment were also assessed. Herbicides were applied twice a season, i.e. in spring after planting and in autumn to control weeds emerging during the season. The efficacy of the herbicide combining both pendimethalin and dimethenamid‑P was the highest in all three seasons. Metazachlor, pendimethalin and dimethenamid‑P provided satisfactory efficacy with adequate soil moisture. Pre‑emergent efficacy of metamitron, linuron and chlorotoluron was not satisfactory, especially in dryer conditions. The synergistic effect of the surfactant and rainfall on the efficacy of pendimethalin in combination with dimethenamid‑P was proved in the dry year only. None of the tested herbicides had a negative effect either on the growth and health status of planted rootstocks or subsequently on budded plants in the following year.

In the present study we investigated the possibility to use air ozone in fruit tree storage. The variables were: rate of ozonization, length of exposure to ozonized air and storage temperature. We assessed the impact of ozone on the vitality of the trees or bench grafted rootstocks, any changes appearing after storage and the feasibility of this technique under real conditions. Supplementary research was done to test the impact of ozonization on the potential occurrence of microorganisms and pests on trees. Results showed that trees can withstand relatively high rates of ozonization except for peach which is the most sensitive fruit; all the ozonization treatments impaired peach vitality. Other species withstand three months of storage in 1 °C and one hour of exposure to ozone in fortnight intervals without a significant impact on their vitality. A higher (5 °C) storage temperature with or without ozonization decreased the vitality of trees. Although it has been proved that ozonization can suppress damage‑causing microorganisms (bacteria and fungi) on trees, the fortnight frequency of ozonization did not prevent mould to develop. Results also indicated the potential effect of ozonization on the disinfestation of plant material from overwintering pests. The main operation restrictions of ozone exposure is the ability of ozone to decompose some materials and that it is harmful to human health.