Vol. 16 No. 1 (2010)

Published January 3, 2010

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  • The role of meteorological variables of blossoming and ripening within the tendency of qualitative indexes of sour cherry
    7-10.
    Views:
    211

    We analyzed the relationship to sour cherry quality parameters of average temperature, maximum temperature, minimum
    temperature, night and day-time temperature, precipitation and climatic water balance variables. Three cultivars of sour cherry were included
    in the selection: “Debreceni bôtermô”, “Kántorjánosi”, and “Újfehértói fürtös”.We conducted regression analyzes on the three varieties, but
    present only those that proved to be the best fit.We couldn’t find any significant differences in the weather tolerance of the varieties. The data
    base of sour cherry quality parameters covers the 1998 to 2008 intervals. The researched parameters were the following: dry matter content
    (%), sugar content (%), C-vitamin (mg), total acid content (%). Maximum temperature, the difference of night and day-time temperature and
    minimum temperature all have a significant correlation with the investigated quality parameters of sour cherry. Minimum temperature shows
    a quadratic relationship with sugar content, while night and day-time temperature differences show the same with dry matter content. The
    other weather parameters had a linear correlation with the quality parameters of sour cherry. The research results show that an increasing
    amount of precipitation causes decreasing tendency in total acid content of sour cherry, so that increasing temperature has a positive influence
    on total acid content. Big differences in night and day-time temperature also has positive effects on the dry matter and sugar content of sour
    cherry while the amount of precipitation has a negative effect. High minimum temperatures cause decreasing sugar content respiratory energy
    losses are significant if dawn temperatures do not drop considerably.A more favourable climatic water balance has a positive effect on vitamin
    C content in cases of a large negative water balance, vitamin C content is generally low.

    204
  • Climatic indicator analysis of blooming time for sour cherries
    11-16.
    Views:
    171

    County Szabolcs-Szatmár-Bereg produces more than the half of the total sour cherry grown in Hungary. Successful production, i.e. yield, depends largely on weather conditions. Most attention should be paid to the weather during the blooming period, being most decisive from the points of view of quality as well as quantity. In order to predict yields expected, the characterisation of the most important weather parameters is necessary. For that purpose, the database of the Institute of Research and Extension Service for Fruit Growing at Újfehértó Ltd. has been utilised. Records of weather conditions were collected throughout the period 1984-2005, i.e. daily minimum, maximum and mean temperatures (°C), precipitation (mm), and phonological diary of sour cherry varieties ’Újfehértói fürtös’, ’Kántorjánosi’ and ’Debreceni bôtermô’. Data of 7 indicators have been traced: number of frosty days, the absolute minimum temperatures, means of minimum temperatures, number of days when daily means were above 10°C, means of maximum temperatures, number of days without precipitation, and number of days when precipitation was more than 5 mm. On the one hand, we surveyed the changes; on the other hand, estimates have been attempted for the future changes expected during the following decades. The indicators being associated with certain risky events may serve for the prediction of the future recommendations to prevent damages.

    184
  • Connection of fertilization conditions of sour cherry and meteorological parameters
    17-21.
    Views:
    201

    Our analyses showed that the degree of free fertilization is mostly influenced by maximum temperature and sunshine duration.We found that free fertilization ratio increases with higher daily maximum temperatures; similar results characterise sunshine duration as well, namely we observed higher free fertilization ratio at higher sunshine duration values. Total amount of precipitation during the period between blossoming and maturity and the difference between the average daytime and night temperatures have an important role in the tendency of maturity time. Photosynthesis and respiration are essentially significant in the development of biological systems. These two processes are mostly regulated by the daytime and night temperatures. Therefore, it is not surprising that if the difference between daytime and night temperatures is large, it means intensive photosynthesis and a low degree of respiratory loss. Under these conditions intensive development and ripening can take place; however, in case of a low temperature difference intensive respiration slows down the process of development. Duration of ripening is also significantly influenced by the amount of precipitation of the period between blossoming and maturity.Abundant precipitation slows down the process of ripening, while dry weather accelerates it. Self-fertilization takes place in a space isolated from the environment. In spite of that, we found that effectiveness of self-pollination significantly depends on the meteorological conditions. Degree of self-fertilization is influenced directly by temperature and indirectly by other climatic parameters. We found a significant connection between the values of maximum and minimum temperatures during blossoming and the ratio of self-fertilization. Increase of maximum temperature reduces the effectiveness of self-pollination.A 1 °C increase of maximum temperature reduces self-fertilization ratio by 0,6%. In the case of minimum temperature we can state that the morning minimum temperature of 7,5–8,5°C is the most favourable. If minimum temperatures are under 4 °C or above 12 °C, self-fertilization ratio reduces to the quarter of the value characteristic at 8 °C. We believe that the effectiveness of self-fertilization can be improved considerably by the rational placement of isolator bags within the crown area, avoiding their placement to the external, western crown surface.

    180
  • Comparison of varying pollen source on productivity of sour cherry (Prunus cerasus L.) cultivars
    23-26.
    Views:
    192

    Fruit set of five sour cherry cultivars (‘Újfehértói fürtös’, ‘Éva’, ‘Petri’, ‘Pándy 279‘ and ‘Csengôdi’) of eight years-old trees grown in Újfehértó, located in the Eastern north part of Hungary have been studied over two years (2008 & 2009). Following reciprocally cross-pollination, free-pollination, self-pollination (autogamy) artificial self-pollination (geitonogamy) were studied. The results show that both maternal and paternal parent cultivates had significant effects on the percentage fruit set. Significant differences have been found in fruit set among years and among pollination treatments. Fruit set of free-pollinated Pándy 276 cultivar was low and seasonally highly variable. The yield of this cultivar on self-pollinated flowers was nearly 0%, and in this treatment the maximum yields did not reach 10% in any of the examined cultivars. There was no significant relationship in the fruit set of free-pollination and natural self-pollination treatments.

    173
  • Analyses of Hungarian sour cherry germplasm with simple sequence repeat markers
    27-31.
    Views:
    193

    Twenty-four sour cherry cultivars (genotypes), belonging to four cultivar groups were fingerprinted using microsatellite markers. All genotypes have been arisen from the Carpathian basin, which could be secondary gene centre of sour cherry, since its progenitor species, ground cherry and sweet cherry overlap here. Five SSR primer pairs, earlier used for fingerprinting Turkish sour cherry germplasm were tested. None of the five primer pairs showed any polymorphism within the cultivar groups. The primer pairs were able to distinguish between the cultivar groups. The Oblacsinszka and the Cigánymeggy cultivar groups were the most difficult to separate, while the Pándy cultivar group was the most distinguishable.

    217
  • Effects of self and cross pollination on fruit set and fruit quality of sour cherry cultivars
    31-36.
    Views:
    275

    An experiment conducted using factorial based on randomized completely block design during 2005 and 2006. Flowers of Érdi bőtermő, Érdi jubileum and Cigány meggy before anthesis and in balloon stages were isolated with paper bags from guest pollens and pollinated in appropriate time. The averages of final fruit set showed the advantage of open pollination (14.6% fruit set) in compare with artificial self pollination (13.0% fruit set) and natural self pollination (4.4% fruit set). Siah mashhad sweet cherry cultivar with more than 70% overlap of flowering and 9.8% fruit set in 2005 and 17.9% in 2006 was the best among applied pollinisers for Érdi bôtermô sour cherry cultivar.Also, Siah mashhad sweet cherry with more than 50%overlap of flowering time and 25.8%fruit set was the best polliniser for Cigány megg. Among the pollinisers, Siah mashhad was the best for Érdi jubileum with more than 50% overlap and 15.22% fruit set. Meanwhile, pollens of Siah mashhad caused the increase of fruit size in Cigány meggy cultivar. phenomenon. Pollens of Siah mashhad caused reduction in total soluble solids of Érdi bôtermô fruits, however, it does not have any significant effect on the acid rate of fruits.

    256
  • New evaluation method to detect physiological stress in fruit trees by airborne hyperspectral image spectroscopy
    37-40.
    Views:
    160

    Nowadays airborne remote sensing data are increasingly used in precision agriculture. The fast space-time dependent localization of stresses in orchards, which allows for a more efficient application of horticultural technologies, could lead to improved sustainable precise management. The disadvantage of the near field multi and hyper spectroscopy is the spot sample taking, which can apply independently only for experimental survey in plantations. The traditional satellite images is optionally suitable for precision investigation because of the low spectral and ground resolution on field condition. The presented airborne hyperspectral image spectroscopy reduces above mentioned disadvantages and at the same time provides newer analyzing possibility to the user. In this paper we demonstrate the conditions of data base collection and some informative examination possibility. The estimating of the board band vegetation indices calculated from reflectance is well known in practice of the biomass stress examinations. In this method the N-dimension spectral data cube enables to calculate numerous special narrow band indexes and to evaluate maps. This paper aims at investigating the applied hyperspectral analysis for fruit tree stress detection. In our study, hyperspectral data were collected by an AISADUAL hyperspectral image spectroscopy system, with high (0,5-1,5 m) ground resolution. The research focused on determining of leaves condition in different fruit plantations in the peach orchard near Siófok. Moreover the spectral reflectance analyses could provide more information about plant condition due to changes in the absorption of incident light in the visible and near infrared range of the spectrum.

    194
  • Effects of irregular cropping on nutrient uptake and status of apple trees
    41-44.
    Views:
    185

    Produce of harmonic nutrient balance and status of trees is basic task of growers for qualified fruit growing. The role of crop loaded is essential to grow the productivity of trees without nutrient disorder or other nutritional problems. To reduce the frequency of biennial bearing there are some ways (site and species selection, crop regulation, irrigation, nutrition etc.) from them one is the best easy way the proper site and species oriented nutrition. Sometimes the responsible for irregular cropping is the insufficient fertilization. Observed irregular cropping at two apple cultivars (Malus domestica Borkh., cv. ‘Summerred’ and cv. ‘Mutsu’) in an integrated apple orchard at Hajdúnánás-Tedej, in 2007 resulted a chance to determine nutritional status of “bearing” and “non bearing” trees and investigate the effects of irregular cropping on nutrient uptake and possibilities of correction. Our results pointed out that irregularity is connection on nutrition status of trees. Irregular cropping results in insufficient nutrient uptake and disharmony of nutrients. For this reason, the establishment of nutrient status of “non bearing” trees is could permit a chance to correct and improve the nutrient supply of trees which help to breakdown the vicious circle of irregularity.

    182
  • Some aspects of disease management of cherry leaf spot (Blumeriella jaapii) with special reference to pesticide use
    45-49.
    Views:
    453

    In this review, some aspects of disease management of cherry leaf spot (Blumeriella jaapii) are summarised with special reference to pesticide use. In the first part of the review, we show the non-chemical control approach (e. g. removal of fallen leaves, planting resistant cultivar) against leaf spot. In the second part of the review, the effect of pesticides including fertilizers (urea) and fungicides on cherry leaf spot are discussed. Special attention are given to the fungicides of copper, dodine, captafol, captan, benomil, chlorothalonil, sterol demethylation inhibitors (e.g. fenarimol, fenbuconazole, myclobutanil, tebuconazole), and strobilurins about their effectiveness against cherry leaf spot. In the final part of the review, possibilities of cherry leaf spot control are discussed in integrated and organic cherry orchards.

    424
  • Some aspects of reduced disease management against Monilinia spp. in sour cherry production
    50-53.
    Views:
    174

    The aim of this study was first to test the in vitro effeicacy of some fungicides against brown rot of sour cherry, and secondly to evaulate the effectiveness of reduced spray programmes against brown rot in integrated and organic sour cherry orchards. In vitro efficacy of 7 fungicides (Champion 50 WP, Kocide 2000, Nordox 75 WG, Olajos rézkén, Kumulus S, Rézkén, Rézoxiklorid) and another 6 fungicides (Score 25 EC, Efuzin 500 SC, Systane, Folicur Solo, Zato Plusz, Rovral) approved in organic and integrated production systems, respectively, were tested against brown rot of sour cherry. Altogether four spray programmes were performed i) standard integrated: sprays followed by forecasting systems during the season, ii) reduced integrated: sprays followed by forecasting systems but only 75% of the spray numbers used during the season-long spray programme, iii) standard oragnic: sprays applied every 7–14 days during the season and iv) reduced organic: 60% of the spray numbers used during the season-long spray programme. In vitro results showed that fungicides (with active ingredients of copper and sulphur) applied in organic production showed relatively high percent growth capacity of Monilinia fungus. Rézkén showed the highest and Kumilus S the lowest efficacy against brown rot. Fungicides applied in integrated production showed relatively low percent growth capacity of Monilinia fungus. Score 25 EC showed the highest and Rovral the lowest efficacy against brown rot. Field study showed that reduced spray programmes did not increase significantly brown rot incidence in the integrated field. However, brown rot incidence increased significanly (above 30%) in the reduced spray programme for the organic orchard.

    189
  • A study of processes active in regeneration of different sweet cherry varieties
    55-57.
    Views:
    202

    Cherries belong to the group of fruit trees, which require little attention in pruning. The process of getting bald branches is less accentuated, which is associated with the light requirement of organs changing along with the aging process. The growing habits of the varieties (length and number of growing shoots, etc.) is closely related with the productivity of fruiting parts. The ability of regeneration and the functional effectiveness of fruiting structures are expressed by the distribution according to their age. The differences registered justify the necessity to develop pruning policies for each particular type of variety. For that purpose, we have to examine the age dependency of the processes related to regeneration, which may serve as starting point of a pruning strategy. Growth of some parts should be stimulated in order to develop or regenerate fruiting parts. Some branches need to be rejuvenated, partially, as an antidote to progressive senescence. Every intervention is aimed to strengthen the development of the most productive constructions. Reactions induced by rejuvenation should be expressed in fruiting intensity. A pruning program adapted to the particular variety as well as to the actual phase of a rotating pruning system should anticipate results.

    190
  • Effect of variety and cultivation technology on phenols and antioxidant activity of sweet and sour cherry
    59-61.
    Views:
    221

    The goal of the present work was to compare different sweet and sour cherry cultivars and cultivation methods (bio/integrated) with respect to polyphenol content and antioxidant activity. The concentration of total polyphenols ranged between 880–1050 mg kg-1 of fresh fruit, whereas antioxidant activity expressed as TEAC was found to be between 5.4 and 10.3 mmol kg-1 for the sweet cherry cultivars examined. In case of sour cherry the level of polyphenols ranged between 1283 and 3490 mg/kg fresh edible part of the fruit. Antioxidant activity was recorded between 15–32 mmol kg-1 for the different sour cherry cultivars included in this work. After one-month storage at low temperature, the total phenols and antioxidant activity decreased by 2–40% in the sour cherry cultivars studied. The anthocyanin content in cherry cultivars was less (131–312 mg kg-1) than the135–1893 mg kg-1 found in sour cherries. Anthocyanin level was higher in samples produced under organic farming conditions than in those produced with integrated cultivation.

    189
  • Some physical properties of sweet cherries
    63-70.
    Views:
    168

    The determination of the optimal time of the mechanical harvesting of sweet cherries has a great importance not only to prevent the fruit from mechanical injury but to find the optimal setting parameters of the harvesting machine. The primary objective of the experiments was to determine the force and work required to detach the stem from the limb and the fruit from the stem. Furthermore to measure the three main sizes (width, height, thickness) of the fruits in order to determine the sphericity, and also the pulp-stone ratio by measuring the mass of the fruit with the stone and then the mass of the stone. The average sizes of the fruits: width 19.62–27.76 mm, height 17.83–24.54 mm and thickness 17.30–23.60 mm. The stem length varied between 28.69 mm and 55.80 mm. The sphericity of each variety was above 90%. The average mass varied between 3.63 and 9.68 g. The stone mass turned to be between 0.27 g and 0.42 g. The stone-pulp ratio varied between 3.7%and 7.7%. The average pulp mass varied between 3.35 g and 9.32 g. The average values of maximum loads required to detach the sweet cherries from the stem varied between 3.23 N and, 4.12 N. The force required to detach the stem from the limb was 50–90% higher than the force needed to tear the fruit from the stem.

    182
  • Assessment of apple varieties based on consumer judgement in integrated production for fresh consumption
    71-74.
    Views:
    197

    In a former paper we treated the same relation comparing varieties frown in the biological or organic system of growing, now the tests have been performed with samples grown by the integrated system. The scores registered properties as taste, skin, colour, consistency and size. In addition, we also explored the relation between general impression and the individual properties.As first purpose, we started with collecting primary data on 15 samples taken from fruits grown by the integrated method and kept over 60–90 days in a store, then offered to the consumers. The test is based on an organoleptic assessment (records are registered in a questionary). The individual judgements are processed and coefficients of correlation between the traits (taste, skin, size, colour) calculated. The validity of the mathematically proved relations is considered to be decisive in judging the preferencial consumption of fruits.

    194
  • Cost and profit analysis of sour cherry production for industrial purposes in Hungary
    75-79.
    Views:
    237

    Our main objective in this present study is to evaluate the profitability and efficiency of sour cherry production by a complex economic analysis of its technological process. We concluded that the per kilogram prime costs range between 80 to 90 HUF/kg in case of sour cherry for industrial purposes. On this basis, it is clear that the 50 to 90 HUF/kg regular selling prices of previous years do not make profitable production possible. Under the present market conditions even considering per hectare average yields of 10 to 15 tons the establishment of sour cherry orchards is not economical, the internal rate of return is below the interests of money-market and the recovery will not be happened even during the whole life-time of the orchard. In this way the domestic enterprises should not only raise the yields but realize technological changes (e.g. mechanic harvesting) in order to decrease the production costs in a significant way and to maintain a profitable sour cherry production. It is expected that the enterprise farming on great land (several ten hectares), being settled for mechanic harvesting (subordinating everything to this), reaching yields of 15 to 20 tons per hectare, producing on high technological and input levels, having specialized knowledge will stay on the sour cherry market far in the future.

    200
  • Climate change impacts and product lines
    79-83.
    Views:
    185

    This paper summarizes the main effects of extreme weather events on agricultural production and demonstrates their economic consequences. For cost-benefit analysis of economic impacts and for determination of risk levels simulation models are needed that contains the relationship between product line levels and elements. WIN-SIM model is developed for this goal, specialized for wine production. The model is suitable to analyze the market share, the cost and income relations as well as the relation structure of the product lines. The four levels of the model (site, vine growing, wine production and wine market levels) have individual values added from the aspect of end product, where the product line sets out from the site level and gets through the levels up to the consumer segments. Theoretically, all elements can be connected to any element of the next level and sublevel, but there are “prohibited contacts” because of professional, regulation or production practice reasons.

    179
  • The Hungarian peach production risks
    85-89.
    Views:
    152

    Hungary possesses very good agroecological conditions even in a European comparison. Agriculture and food production is highly important despite its decreasing relative economic significance, since providing high quality and affordable food for the population is a basic social necessity and one of the decisive factors in quality of life. The development of vegetable and fruit production is of great importance both from a healthy nutrition as well as from a comparative advantage (cheap labour, expertise, production traditions, favourable climate) point of view.Vegetable and fruit consumption per capita is lower than in developed countries, which is a decisive indicator of healthy nutrition, but improvement is continuous and desired. Appropriate quality and quantity in production is a requirement to meet customers’ needs in a highly competitive market from one year to the next. Hungary can only be competitive if production results are improved while risks are reduced. Fruit production is a sector with high capital requirements, risk assessment is very important from a production, investment as well as from a national economy point of view. Our examinations will focus on production risk, which is present in the annual fluctuation of average yields, especially as a result of extreme weather factors.

    201
  • Conditions and outlooks of growing stone fruits
    91-98.
    Views:
    187

    Conditions and outlooks of growing stone fruits

    224
  • The future of the Hungarian sour cherry growing branch
    99-104.
    Views:
    181

    The present study deals with the actual situation of the Hungarian sour cherry production in order to outline the chances of the future and the trends of the development anticipated. The general conclusion accepted that on the long run Hungarian sour cherry production ought to be reorganised. The conditions of keeping the position on the international market are outlined: integration of small farms into large plantations (several times 10 hectares), introduction of mechanical harvest and high (15–20 t/ha) yields. For all that, adequate expertise should be developed on the cooperative farms, where the up to date technology could be applied with innovative initiatives. Small farms (up to 1–2 hectares) and home gardens have no chances to stay on the competitive market. The actual volume of sour cherry of 40–70 thousand tons per year cannot be increased in the future. The sour cherry area was 16 000 ha in 2001, the actual is around 12–13 thousand, and will decline during the following 5 years to less than 10 thousand hectares.

    209
  • The situation of horticultural family farms in Hajdu-Bihar County
    105-108.
    Views:
    136

    The main aim of this research work is to study horticultural farms in Hajdú-Bihar County, that mobilize labour and capital for the sake of agricultural production, namely family farms. During this study work we tried to chart the main characters, the conditions of functioning, their profitability and its use possibilities, their external contacts and the resource of information of these farms, beside this to investigate the relationships between these parameters. Parallel to this we tried to compensate the relatively high deficiency of information by empirical research work. This deficiency is the characterization of farmers and the inducement of farming and its conditions both on the level of county and state. By our empirical research work we have made a comprehensive position paper that shows the conditions of farms and farmer populations, as well. Two hundred questionnaires were evaluated. The percentages of horticultural farms were 25% from all questionnaires. Above all this paper is looking for the answer to the following questions: How and by which sources do farmers develop and extent their farms? How do farmers see their own future, what kind of aims do they have?Who will stop and who will go on producing? The collected information on the whole may help to make much more flexible legislatives and administrative regulations, although the survey covered only one county.

    177
  • Response of alternate bearing of “Badamy sefid” Pistachio cultivar to foliar application of some macro and micro elements
    109-112.
    Views:
    205

    Response of “Badamy sefid” Pistachio trees to spraying of fertilizer was studied over two years (2006–2007). The boron and zinc fertilizer were used just on swelling time of female flower bud in compare to no fertilization (control). Also nutritional solution combined of nitrogen (400 ppm), phosphorus (P2O5) (380 ppm), potasium (K2O) (520 ppm), Fe (5 ppm), Cu (2 ppm), Zn (2 ppm), Mn (2 ppm) in 1000 liter water per hectare sprayed at first week of May, third week of June and July). The concentration of some macro and micro elements in flower bud and in leaves, also productivity (g/shoot sectional area) mean nut weight, fresh weight of nut per cm2 branch cross sectional area, blanks nuts %, non-split nut %, new shoot growth length after cessation of growth and remained flower bud (%) at the next spring were recorded for the different treatments. The results showed that boron and zinc concentration increased in the bud of sprayed trees in compare to control. Application of nutritional solution decreased the flower bud abscission, also resulted in increased vegetative growth, nut weight, and productivity of trees. In conclusion, spraying of fertilizers in the suitable time to the pistachio trees might be a useful method in decreasing flower bud abscission and mitigating the alternate bearing.

    233
  • Ecological drought resistance and adaptability of apple varieties
    113-122.
    Views:
    281

    For adequate yields in apple plantations, during the long growing period of the fruit primordia, one of the decisive factors is water supply. Indicators of stress are valuable signs for the diagnosis of drought and necessity of watering, i.e. planning the irrigation of plantations. The aim of the present study was to find reliable signs of water stress on apple trees and at the same time conclude on the drought tolerance of different varieties. The plantation of apple varieties grafted on various stocks and cultivated according to different systems (irrigated, non irrigated, integrate and biological) has been examined continuously by leaf analysis. Along the period of growing fruits, measurements were made in the field, then the leaf samples were analysed in the laboratory for composition of pigments, carbohydrates and antioxidants, as well as the histology of the tissues checked. Without irrigation, the mean leaf mass and the relative chlorophyll content (SPAD) of the variety Idared on M4 stocks increases beyond the values of 50 SPAD, whereas on M26 stock and integrated system, it declines. In the collection of varieties, grown according to the „integrated” system, during the development of fruits, ‘Gála’ and ‘Remo’ varieties have been affiliated to the “less susceptible” group regarding drought tolerance because of the leaf morphology, structure and content of SPAD and antioxidants. However, ‘Idared’ and ‘Jonagold’ belong to the “susceptible” group. To the same group are ranged the ‘Akane, Red Rome vanWell, Pink Lady’ varieties. Those varieties reacted to a short period of drought by increased production (content) of carbohydrates. Regarding changes of carbohydrate content ‘Greensleeves’ and ‘Ozark Gold’ varieties belong to the moderately water dependent (requiring) group. In the field, SPAD-tests facilitated the measurement of nutrient-uptake and incorporation, which is proved by the tight correlation between the data of SPAD and the increment of leaf weight (r=0.76–r=0.88), however, this depends on the variety too. SPAD is an indicator of water supply and is related with the density of stomata, cannot used for the selection of water-exigent varieties but for (drought) tolerant ones. In integrated culture, the (drought) susceptible varieties display (water-soluble) hydrophilic and lipophilic antioxidants (ACWand ACL resp.) the quantity of which may have some role in drought tolerance.

    252