Search

Search Results

• Disease progress of apple scab caused by Venturia inaequalis in environmentally friendly growing systems

  56-62.

  I. J. Holb

  Views:

  228

  Progression of apple scab epidemic in six apple cultivars, including two current and susceptible (Gala Must, Elstar), two old (Egri Piros, Darusóvári), and two resistant cultivars (Relinda, Releika), were described and analysed in a two-year-study, in two environmental-friendly growing systems (organic and integrated). Curves of disease progress, linear regression analysis of transformed disease incidence data and Area Under Disease Progress Curves (AUDPC) were used to characterise the epidemic processes of the selected cultivars. Cumulative disease progress curves showed continuous but asymmetrical scab development on the moderate or highly susceptible cultivars Gala Must, Elstar and Egri Piros, and on the tolerant or resistant cultivar Darusóvári and Relinda, in both systems. The cultivar Releika showed no symptoms either on fruit or leaf. In linear regression analysis, the best linearisation was given by logistic transformation. Adequate parameters leaf disease incidence rate, of obtained from a regression equation, were higher in the organic system than in the integrated system. Values of AUDPC showed great differences in leaf disease incidences among cultivars and between growing systems. AUDPC gave more differences for comparison of progresses of disease epidemic than growth rate of disease in different systems of disease control. Moreover, the obtained results were compared with similar studies on different pathosystems, and biological interpretations of the analyses are discussed below.

• 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.

   

• Economics of apple-storage I: Comparative time series analysis of apple producer prices in Germany and Hungary

  75-79.

  Z. Lakner

  F. Apáti

  Views:

  222

  Based on standard econometric methods the article analyses the time series of fresh apple producer prices in domestic markets of Germany and Hungary. In Germany, as a consequence of high storage capacities the quantity offered in different parts of the season is relatively stable, that’s why only a rather limited price increasing can be detected. In Hungary, as a consequence of the limited storage capacity this fluctuation is much more important. The modern methods of time series analysis (ARIMA models, stepwise regression) can be efficiently applied for forecasting of price movements.

• Relationship beetwen the phenological features of pear cultivars and the main meteorological parameters in a gene bank with 555 pear

  59-63.

  L. Lakatos

  S. Musacchi

  T. Szabó

  G. Kocsisné Molnár

  Z. Szabó

  M. Soltész

  J. Nyéki

  Views:

  229

  The trees observed are grown at Ujfehert6, Eastern Hungary in a gene bank with 555 pear cultivars. Each of the cultivars was monitored for its dates of: the beginning of bloom, main bloom and the end of bloom and ripe phenophasis separately between I 984 and 2002. We analyzed the statistical features, frequency, distribution of these phenophasis and its' correlation the meteorological variables bet ween the interval. During this period the meteorological database recorded the following variables: daily mean temperature (°C), daily maximum temperature (0C), daily mini m um temperature (0C), daily precipitation (mm), daily hours of bright sunshine, daily means or the differences between the day-time and night-time temperatures (0C). For the analysis of data the cultivars have been grouped according to dates of maturity, blooming period as well as types of the seasons. Groups of maturity dates: summer ripe, autumnal ripening, winter ripe cultivars. Groups of blooming dates: early blooming, intermediate blooming, late blooming cultivars. At all the separated groups we analyzed the relationship between phenophasis and meteorological variables. During the 18 years of observation , the early blooming cultivars started blooming on 10-21 April, those of intermediate bloom date started flowering bet ween 20 April and 3 May, whereas the late blooming group started on 2- 10 May. Among the meteorological variables of the former autumn and winter periods, the winter maxima were the most active factor influencing the start dates of bloom in the subsequent spring. For the research of fruit growing-weather relationships we used simple, well known statistical methods, correlation and regression analysis. We used the SPSS 1 1.0 software for the linear regression fitting and for calculation of dispersions as well. The 1ables made by Excel programme.

• Prospects of mango fruit powder production at farm level and its utilisation during mango off-season in Ghana

  V. O. Edusei

  G. Essilfie

  J. Ofosu-Anim

  F. K. Saalia

  V. Eziah

  Views:

  368

  Mango (Mangifera indica) is an important fruit served to customers as fresh-cut fruit, juice, ice cream and yogurts in many fruit juice joints, restaurants and hotels in Ghana. However, the crop’s highly seasonal and perishable nature is a challenge for food processors and farmers. Preservation of the fruit in dry particulate form can serve as a substitute in off-seasons. The study sought to determine mango fruit powder production prospects at the farm level and explore its potential use as a substitute during the off-season. Farmer groups and food enterprises were therefore interviewed. The study showed that Keitt and Kent varieties were the most cultivated varieties because of market demand and high yield. However, an average annual fruit loss of 29.8% at the farm level was observed. Postharvest extension delivery service to farmers is inadequate, and where available, frequency of contact is irregular. A limited number of farmers received training in fruit processing; and few were engaged in transformational value addition activities but were willing to add value through processing into powder. Probit regression analysis showed that a unit increase in training would increase transformational farm level value addition into mango fruit powder by 22.9%. The majority of the food enterprises source fruits within Ghana while 79% experienced mango fruit shortage in the off-seasons. Only a few of the enterprises used mango fruit-based substitutes to serve customers in off-seasons. Probit regression analysis showed that a marginal increase in processors’ use of substitute significantly (p≤0.05) increased willingness to use mango fruit powder as a substitute by 47%. The study has revealed that local production of mango fruit powder could serve as a substitute to fill the seasonal gap in mango supply and also reduce post-harvest losses.

   

• Analyses of the pathogen and weather components of disease progress for modeling apple scab epidemics in integrated and organic production systems

  101-106.

  I. J. Holb

  Views:

  226

  The pathogen and weather components of apple scab disease progress were analysed in a three-year study, in two environmental-friendly production systems (organic and integrated) on cvs. `Idared', `Jonica' and 'Mutsu'. Linear regression analyses of transformed disease incidence and severity data and "area under the disease progress curves" (AUDPC) were used for the analysis of the pathogen component. To evaluate the role of the weather component in apple scab epidemic, first, the weekly disease increase was determined at a certain week (n). Weekly disease increase was related to rainfall, relative humidity, Mills' wetness period, temperature and interaction between temperature and relative humidity. Five different periods were used in the analyses: i) week (n-1), ii) week n(n-1), iii) week (n-2), iv) week (n-1)(n-2) and v) week n(n-1)(n-2). In the analyses of the pathogen component, the best transformation function was the logistic one. Regression analyses showed that disease growth rates were higher for disease incidence and for the organic production system than for disease severity and for the integrated production system, respectively. Disease growth rates for leaf incidence were higher than fruit incidence on all the three cultivars. AUDPC values showed great differences in both leaf and fruit incidences among cultivars and between the two production systems. The results the of analyses of the weather component showed that the best relationships between disease increase and weather parameters were found for fruit incidence and leaf incidence in week (n-2) in the organic and integrated production systems, respectively. Results also demonstrated that in week n(n-1) temperature played a more important role in the fungus development than the water parameters (relative humidity, rainfall and leaf wetness). Consequently, infection process is significantly dependent on almost all weather parameters, but during the incubation period the most important weather parameter is the temperature. Results were compared with similar studies and biological interpretations of the analyses are discussed.

• An investigation of genotype-environment interaction and stability for pea (Pisum sativum L) seed yield

  53-55.

  L. Csizmadia

  F. Kormos

  Views:

  116

  Eighteen pea breeding lines and three check cultivars were tested in two years with and without irrigation. The linear regression can explain only a small part of GEI so the use of regression technique was not possible for interpreting the data. In this case the ecovalence, stability variance and superiority measure stability parameters cannot describe properly the genotype's response. With the AMMI method it is possible to group properly the genotypes according to their response.

• Comparative study of plum cultivars belonging to different taxons during 1980-1996

  13-19.

  D. Surányi

  Z. Erdős

  Views:

  158

  The program of the Research Institute of Cegléd, comprises the acclimation and selection of 7 Prunus-species and 39 cultivars grafted on Myrobalan C. 679 (P. cerasifera) seedling stocks. In addition two varieties have been investigated on three different rootstocks each: Myrobalan C. 174 (P. cerasifera), Bitter almond C. 449 (P. arnygdalus var. amara) and Sweet almond C. 471 (P. amygdalus var. dulcis). Fruits of commercial quality are produced maroly on some cultivars of P. salicina-, P. italica- and P. cerasifera character. Authors explain the three possible causes of low yields experienced in non-European plums:

  1/ unfavorable environmental conditions

  2/ lack of irrigation and

  3/ superficial information concerning the variety, rootstock and adequate traditions as well as growing practices.

  A rather tight correlation has been stated between blooming dates and the main ripening period. However, the early blooming time alone cannot be considered as the cause of low productivity. The decay of plum trees is attributed to special ecological requirements and phytosanitary problems of the foreign plum cultivars. The analysis of regression revealed stochastic relations involving several other characters too, which facilitate the planning of cross-combinations in the breeding program.

• Economic figures of apple production at national level of Hungary

  103-105.

  J. Felföldi

  N. Ványi

  J. Nyéki

  Z. Szabó

  M. Soltész

  Views:

  314

  Apple is the most important fruit in Hungary, despite of that, it is a paradox that during the last years, apple growing was the most unsuccessful enterprise among the prosperous ones in the country. The real cause of regression was unequivocally the low price, which could be obtained and the inadequate structure of apple varieties. A heavy problem is still the overweight of the quality doomed to supplying the processing industry instead to the fresh consumption. In order to improve the conditions, we aimed the economic analysis of the five year long period, 2005-2009, to trace the changes involving values and costs of production, income and all conditions combined with this activity. The data presented in the paper are means of a heterogeneous population of values, which cannot be utilised for immediate use in management, but they may reveal the challenges and tendencies of that branch in economics.