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• 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.

• Physiological and biochemical evolution of peach leaf buds during dormancy course under two contrasted temperature patterns

  15-19.

  G. B. Leite

  M. Bonhomme

  G. L. Putti

  G. Petel

  J. L. Petri

  R. Rageau

  Views:

  120

  Budbreak anomalies in temperate fruit trees grown under mild conditions have often been described. However, only few authors approached the physiological evolution of leaf buds all along the dormancy period according to the temperature pattern. The aim of this study was to characterize the evolution of peach leaf bud dormancy through some physiological and biochemical parameters under temperate winter conditions and under total cold deprivation after the endodormancy onset. Two treatments were applied in peach trees cv. Redhaven: (i) Regular Chilling Amounts — RCA and (ii) Total Chilling Deprivation — TCD. Buds were sampled periodically from different parts of the stem (terminal, medium and basal ones). We recorded the evolution of: carbohydrate concentrations (glucose, fructose, sucrose, sorbitol and starch), respiration rate, water contents and energy metabolism (ATP and ADP ratio). The dynamics of these parameters were compared and correlated with dormancy evolution ("one node cuttings" test) and budbreak patterns in plank:. The endodormancy intensity of terminal buds was significantly lower than those of median and basal buds in early October. Under RCA treatment, this gradient faded and the bud endodormancy release was completed at the same time in all positions along the stem. Thereafter, the "cuttings" test indicated that terminal buds grew slightly faster than median and basal buds, and, consistently, budbreak in planta started with the terminals buds, followed by the medians and then by the basal ones. The carbohydrate contents showed a transitory change only when the buds began to grow after the endodormancy was released under RCA. Respiration, water content and ATP/ADP changed dynamics only under RCA and only after the end of the endodormancy (their respective changes were very parallel). The dynamics of none of the tested parameters could be related with the endodormancy dynamics, but respiration, water content and ATP/ADP could be consistent markers of the actual bud growth before bud break (in this respect, ATP/ADP could not show differences between the terminal and axillary buds while respiration and water content could).

• Histological studies on small bulb flower crops

  83-85.

  I. Kohut

  P. Gracza

  T. Tar

  Views:

  159

  Investigations were done in order to obtain more information on the histological structure of bulbs of Allium moly, Allium sphaerocephalon, Muscari armeniacum and corms of Crocus sativus. While starch grain were found in the bulb of Muscari armeniacum, fluid nutrient content were shown in Allium species. Narrow and fleshy scales were found in the bulbs of Muscari. Histological characteristics of Allium moly and Allium sphaerocephalon showed a closer relationship with corms than with the bulbs. To clarify this question, further investigations are needed (Bailey, 1942; Larson, 1980).

• The quality and storage efficiency of some apple varieties as a function of picking date, area of production and duration of storage

  99-103.

  P. Sass

  Z. Lakner

  Views:

  156

  Numerous apple varieties have been tested parallel with traditional Jonathan varieties during four years, 1990-1994 on three different geographical areas of Hungary. The picking time took place at three different times in a year: ten days before the probably optimal picking time, at close-to-optimal picking time, and ten days after the optimal picking time. The effect of storage on quality of fruits have been tested in February, March, and April under circumstances of a semi-industrial storage experiment.

  The results of experience can contribute to answer numerous current, from point of view of practice important topics:

  • The stochastic relations between various fruit quality parameters at different varieties
  • The change of fruit — quality during storage
  • The effect of different picking date on storage losses
  • The possibilities of storage — loss predicting by the utilization of multiple regression analysis.

  The most important results of experiences are as follows :

  1. The starch — degradation test and Streiff — index are well applicable for practical purposes to determine the optimal harvest-date.
  2. On base of analysis of various losses and physiological diseases the high importance of mass loss is obvious. In the variety Jonnee the earlier picking date considerably increased the mass loss. The effect of variety on mass loss is rather limited. In the Jonathan varieties the Jonathan spot was a rather important physiological disease. The late picking time increased the frequency of Jonathan - spot. At optimal date of harvest at Jonnee the frequency of Jonathan -spot was lower, than at Jonathan M 41. In the Jonathan M41 and Jonnee the importance of scald was rather limited, but in the Wellspur Delicious and Smoothee this disease occurred relatively frequently. In the Smoothee the earlier picking time considerably increased the probability of scald.
  3. The multiple regression analysis yielded reliable results, fit for prediction of storage losses and diseases on the base of chemical and physical properties, determined at the time of picking.

   

• Comparison of Xanthomonas arboricola pv. juglandis isolates from walnut trees grown in Romania and Hungary

  65-69.

  A. Bandi

  Views:

  286

  Among diseases that affect walnut, bacterial blight is considered the most important one in all walnut growing areas both from Hungary and Romania. For the determination of susceptibility/resistance of walnut cultivars in our posterior work planned, 61 bacterial isolates were collected from walnuts showing symptoms of blight, with the purpose of isolating Xanthomonas arboricola pv. juglandis (Xaj). The characteristic Xaj colonies, frequently present as saprophytes in the infected plant tissues, were separated from other bacteria according to their morphology, yellow colour, hydrolysis of starch, and oxidation of glucose. All isolates were tested for pathogenicity by hypersensitive reaction on tobacco leaves (Nicotiana tabacum L.), bean pods (Phaseolus vulgaris L) and unripe nuts (Juglans regia L.). Determination of taxonomy of the selected isolates denotes a possible subdivision (races, biotypes) of Xaj occurring in different geographical areas, API 20NE and API 50CH kits were used. Hungarian and Romanian strains showed a high degree of similarity of carbohydrate utilization but slightly differed from the type strain. All were Cu-sensitive.

• The impact of irrigation on the yield and tuber fraction distribution of potato cultivars

  65-70.

  E. Zsom

  Views:

  132

  Potato is one of the most important plants in human nutrition, it is grown in about 140 countries. As a food, it can be prepared in many ways, it is easily digestable with proteins of high biological value, favourable dietetical-physiological characteristics, high starch content and good taste. An increase in its consumption would be favourable from the dietetical point of view. In Hungary, the growing area of potato has decreased considerably for the last decades and we are lagging behind the Western-European countries regarding yield. The experiments were carried out at the Experimental Site of the University of Debrecen at Látókép between 2002 and 2004. In the large-plot experiment, the yields and the distribution of the tuber fractions were studied for 9 medium early cultivars. The experiment was set up on 50 m2 plots on calcareous chernozem soil. Among the studied cultivars, 3 were of Dutch (Desiree, Kondor, Kuroda) and 6 were of Hungarian breeding ('Góliát', 'Hópehely', 'Kankan', 'Lilla', 'Százszorszép', and 'White Lady'). The experiment was set up in 4 repetitions in a randomized design, two of the repetitions were irrigated while two were non-irrigated.