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• Interactive effect of sulphur and lead on the growth of muskmelon (Cucumis melo L.) seedling

  72-76.

  A. El. B. Ragab

  Views:

  124

  The effect of sulphur and lead on growth of muskmelon (Cucmis melo L.) sweet ananas was measured under plastic tunnel. Lead (Pb) was applied at the rate of 0, 75, 300, 600 and 1200 pg/g of soil in factorial combination with treatments of 0, 48, 80, 112 and 224 mg S/kg soils. Muskmelon growth was reduced by increasing Pb concentration and/or by removing S from the growth medium. Lead concentration in plant tissues increased linearly with increasing Pb concentration in the growth medium. Increasing S concentration in solution reduced the effects of the 75-1200 pg Pb /g soil treatments. Increasing S concentration in soil increased shoot and root growth at high levels of Pb. Increased levels of S in the growth medium decreased Pb concentration in shoot and root tissues and increased growth of muskmelon. The reduction in Pb toxicity at high S supply may be due to reduced root absorption of Pb.

   

• The effect of Regalis® (prohexadione calcium) on the reduction of fire blight (Erwinia amylovora) severity in apple trees

  61-66.

  P. Sobiczewski

  T. Bubán

  Views:

  202

  Due to the lack of effective and non-phytotoxic materials for control of the blossom and shoot blight phase of fire blight in pome fruit trees, two novel control strategies have emerged: shoot growth retardation by bioregulators and applying resistance inducer compounds. Prohexadione calcium (ProCa) is the active ingredient of the bioregulator Regalis^® registered in several European countries. The reduction of shoot growth elongation is the most obvious effect of ProCa. Furthermore, it causes significant changes in the spectrum of flavonoids and their phenolic precursors, leading to the considerable reduction of susceptibility to fire blight.

  In Poland, potted one-year-old apple trees of cvs. Gala Must grafted on M.26 and Sampion on M.9 (in 2001) as well as Gala Must on P.60 (in 2002) were treated with Regalis® at a range of concentration of 250, 150 or 150 + 100 ppm, respectively. The inoculation of shoots was made with the strain No.691 of E. amylovora (10⁷ cfu/ml), on the 7th and 21st'day after treatments with Regalis. In Hungary, during the years of 2002 and 2003 one-year-old container grown apple trees of the cvs. Idared/M.9 and Freedom/M.9 were treated with the prohexadione-Ca, the active ingredient of Regalis® 100, 150 or 200 ppm, two weeks before inoculation with the Ea 1 strain of E. amylovora (10⁷ cfu/m1).

  In Poland, the suppression of fire blight in shoots reached up to 80%, depending on concentration and application time of Regalis®. In Hungary, the effect of prohexadione-Ca treatments, determined by the length of necrotic lesion developed, proved to be better than that of streptomycin used for comparison.

• Growth and yield of sweet cherry trees on different roostocks

  98-101.

  K. Hrotkó

  L. Magyar

  G. Simon

  Views:

  243

  The first nine years' results of sweet cherry rootstock trial from Hungary are presented with the aim to select efficient rootstocks for the local ecological conditions. The trials were established in 1989 with 'Van' and 'Germersdorfi óriás' cultivars on the following rootstocks: mahaleb Sainte Lucie 64, Colt, MxM 14, MxM 97. All the trees were headed at 80 cm and trained to a modified Brunner-spindle system. Tree size and yield was measured every year, and the cumulative yield efficiency was calculated.

  Based upon the results, mahaleb cherry SL 64 is a vigorous rootstock with good compatibility and productivity. In comparison to SL 64. the trunk cross-sectional area and canopy spread of the 'Van' trees decreased by 10-15% on rootstock Colt, while the trees of 'Germersdorfi orias' on Colt roostock grew even larger than on SL 64. Considerable 30-40 % reduction of tree size was achieved on trees grafted on M x M hybrids. Trees of `Germersdorfi óriás' showed a similar tendency without significant differences. The cumulative yield efficiency of `Van' trees after nine years was highest on rootstock MxM 14, followed by Sainte Lucie 64. Trees on Colt and MxM 97 rootstocks showed low productivity. `Germersdorfi óriás' produced the highest cumulative yield efficiency on SL 64, followed by MxM 14 and Colt and last MxM 97. Biennial bearing index of heavy cropping 'Van' trees was smaller than that of `Germersdorfi óriás'. The trees of 'Van' on MxM 97 showed higher biennial bearing index, while 'Germersdorfi orias' on different rootstocks showed similar tendency, but without significant differences.

  MxM 14 and MxM 97 rootstocks reduced the crotch angle of the shoots on both sweet cherry varieties which is disadvantegous to spindle training. Slight suckering (1-3/year) of the rootstocks Colt, MxM 14 and MxM 97 were observed during the first few years.

• The size of the canopy of sour cherry trees depends on the time of pruning

  49-52.

  I. Gonda

  Views:

  175

  The intensive culture of sour cherry is achieved by training of trees to form smaller canopies not by means of dwarfing rootstocks but by growth moderation techniques. The rootstocks traditionally used cause vigorous growth, and it is up to the technology to apply procedures less utilised earlier for that purpose. One of those techniques is the transfer of hibernal pruning to the estival period. The best term of the latter is the period of 1-3 weeks after fruit harvest.

  The prolongation of the period of favourable illumination and the reduction of the canopy size facilitate higher densities of planting (number of trees per hectare) and a better exploitation of the crown (specific yield). The regular use of summer pruning resulted also in a better quality of fruit.

• Production technology and fruit tree nutrition

  39-42.

  I. Gonda

  Views:

  152

  Fruit yield quality and quantity are effectively enhanced if healthy vegetative conditions are ensured. These optimal conditions — i.e. the balance between shoot development and yield — can be achieved by the rationalization of the production technologies, such as:

  • reduction of the size of the crown
  • adaptation of the severity and method of pruning to the conditions of the actual year
  • removal of the shoot tips
  • timely fruit thinning

  By establishing an improved level of plant nutrient uptake, this will ensure a healthy balance between shoot growth and yield.

• Effect of gelling agents on in vitro development of Amelanchier canadensis ‘Rainbow Pillar’

  75-79.

  A. Fira

  K. Magyar-Tábori

  I. Hudák

  D. Clapa

  J. Dobránszky

  Views:

  265

  In vitro shoot multiplication responses of Amelanchier canadensis ‘Rainbow Pillar’ were studied on media solidifi ed with different gelling agents. The media were gelled either with 6.8 g l-1 fi brous agar-agar, or 50.0 g l-1 wheat starch, or 20.0 g l-1 Guar gum, or 15 g l-1 Isubgol or 50.0 g l-1 wheat starch mixed with 0.5 g l-1 Phytagel. Shoot cultures were grown for two months, thereafter the multiplication rates (number of newly developed shoots per explant) were counted and the length of shoots were measured. We found that the highest shoot multiplication of Amelanchier canadensis ‘Rainbow Pillar’ occurred on media gelled with Guar gum, while the longest shoots developed on media with Starch. About four-fold shoot number were obtained on media with Guar gum compared to the weakest results found on media gelled with Isubgol. Finally, considering all factors (shoot growth parameters, costs) the most economical gelling agent for Amelanchier canadensis ‘Rainbow Pillar’ was proved to be wheat starch among the tested alternatives which allows a 75.6% cost reduction.