Vol 8, No 2 (2002)
Intense research was made on the pollination of cultivated crop plants in the temperate zone region during the past decade. Some 400 publications appeared on the subject and some additional 150 papers on the effect of pesticides to the most important pollinating insects, the honeybee and the wild bees. Progress of knowledge is discussed in this... paper based on the most important publications. Most new results relate to field crops and deciduous fruit species and much less to field vegetables and small fruits. Great effort was taken to improve insect pollination of crops grown under cover. All these are connected to the utilization of the honeybee as a pollinating agent and much less to native or managed wild bees. However, a number of questions arose partly from the results of latest pollination research and partly from practical experiences in commercial plant production. These indicate several research tasks to understand and to solve the problems possibly in the near future. The questions concentrate on the effectiveness of bee visits in the pollination of individual crop plants and their different cultivars and on the reliable estimate of the overall amount of bees as well as on the control of bee density during the flowering periods of crops for optimal, controlled pollination in the changing environment of agricultural crop production.
Seventeen strawberry (Fragaria x ananassa Duch.) cultivars representing the national list of Hungary, were subjected to RAPD, AP—PCR and STS analysis. Of the 31 decamer and oligomer primers tested 26 primers produced polymorphic patterns. 45 polymorphic fragments were analysed, ranging between 200-2800 by in size. Based on the data,...similarity coefficients (Jaccard index and Simple matching coefficient) were calculated, and dendrograms were constructed using the unweighted pair group method of arithmetic averages (UPGMA). The dendrograms only partly reflect the known pedigree data. Specific RAPD markers were identified for cultivars F5, Pocahontas and Rabunda.
The identification of plant species and study of their genetic relatedness is an important object of plant genetics. The Rosaceae family contains a lot of economically important fruit, ornamental, and wild plant species. The microsatellite markers have been proven to be an efficient tool for description of the genetic relatedness among varietie...s and species. Their evolutionary conserved regions enable them to differentiate among various accessions. This article intends to show proceeded identification and characterization projects on Rosaceae species by using SSR markers. The article presents sources of already published primer sequences. The use of already published primers can highly reduce the cost and duration of this kind of researches.
Experiments were conducted during the period between 1972 and 2002 at three sites in Hungary. At Érd 97, Helvetia 10, and Újfehértó, 3 cultivars were studied in variety collections. Observations were made on the blooming phenology (start, main time, end and length of the bloom period), on the blooming dynamics (the rate of the open flowers...counted every day), on the receptivity of sexual organs, on the fruit set following self- and open-pollination and on the effect of association of varieties in the orchards (choice, rate and placement of pollinisers).
Based on the results the rate of the overlap of the blooming times were calculated and varieties were assigned into five bloom time groups according to their main bloom. Self-fertility conditioned by natural self pollination was studied and good pollinisers were chosen (sweet, sour and duke cherry varieties) for the self-sterile and partially self-fertile varieties.
The necessity of bee pollination was proved by different pollination methods: natural self-pollination, artificial self-pollination, open pollination. Summary: Experiments were conducted during the period between 1972 and 2002 at three sites in Hungary. At Érd 97, Helvetia 10, and Újfehértó, 3 cultivars were studied in variety collections. Observations were made on the flowering phenology (start, main time, end and length of the bloom period), on the flowering dynamics (the rate of the open flowers counted every day), on the receptivity of sexual organs, on the fruit set following self- and open-pollination and on the effect of association of varieties in the orchards (choice, rate and placement of pollinisers).
Small fruits have a modest share in the fruit production of Hungarys. Red currant was grown traditionally in home gardens 60-70 years ago. Commercial production was established only in the surroundings of some town. The black currant was unknown until after Wold War II. An important change occured in small fruit production in the 1950s. Sociali...st countries, which had cheaper labour power, made efforts to meet these demands. In this time we produced 25.000 t.
Presently the country produces 13-15.000 tons currant fruit yearly 60% from this is black currant, which has a better market. It is our own interest to make our currant production more profitable. The currant is the second most widely cultivated soft fruit. Our product is disposed mostly on EU markets.
There was no breeding activity in this field in Hungary earlier. Cultivars used were mostly of foreign origin (W. European; Boskoop Giant, Silvergieter, Wellington XXX, Russian; Altaiskaya Desertnaya, Neosupaiuschaiasya, N. European; Brikltorp, Ojebyn). Besides well-known advantageous this cultivars have also some defects mainly unfavourable—adaptation to climatic conditions, which caused fertilisation problems, reduced the fruit set and uneven growth with decreased yields (Dénes & Porpáczy, 1999). About 140 black currant cultivars were investigated during the last four decades in our variety trials and only four of them were introduced with satisfying yielding capacity (3.5-5.5 t/ha).
The geographic location of Bucharest area, the nature of its soil and its climate offer remarkably favourable conditions for nectarine growing, with juicy and well flavoured fruit, good for fresh consumption and processing.
The five years' investigation (1996-2000) has helped to identify some nectarine cultivars and hybrids (NJN 58, ARK... 165, ARK 139, Morton, ARK 107, Romamer I, ARK 125, Firebrite) with exceptional fruit quality (dry matter content, titratable acidity, vitamin C content, overall sugar, and amount of pectic substances).
Dry matter content varied over the three years from 8.3 to 18.5% (NJN 68), meanwhile titratable acidity varied between 0.26 and 1.08% (Romamer I). Sugar / acidity ratio was within the limits of 8.6 and 36.5 (Nectared 7). Nectarines have high vitamin C content, over 10 mg/100g (Fairlane, NJN 67, Regina, Harko), glucides were found in Firebrite, Romamer I varieties and NJN 21, CIR1T127, HFSR3P4, HNA hybrids.
Some cultivars have been recommended for planting in this southern area of Romania (Crimsongold, ARK 125, Harko, Hardyred, ARK 134), others used as quality genitors (ARK 85, Nectared 7, NJN 21, ARK 21, ARK 134, Fantasia) in breeding projects.
Researches concerning the selection of some nectarine varieties as genitors for the breeding program in Romania
Within the period of 1994-1999, variability of fruit weight and width was evaluated in altogether 24 apricot genotypes. It is concluded that the genotype and climatic conditions of individual years are the factors causing variability in these two parameters of apricot fruits. Variability of fruit weight was significantly higher (approximately 3...-times) than that of fruit width. When evaluated on the base of their width, 75.0% and 95.8% of apricots were classified into the groups of extra and first quality, respectively. As genotypes with the maximum fruit width (i. e. above 50 mm) the following cultivars were classified: 'Velkopavlovicka LE-6/2', 'NJA-1', 'M 45', 'M-25' and lednicka (M-90-A)'. The value of fruit width (in mm) corresponded with its weight (in g) only within the range of 40 — 45 mm. With the increasing and/or decreasing size of apricot fruit the changes in fruit weight were more pronounced than in those in fruit width. Within the set of genotypes under study, this relationship may be expressed by the equation y = 0.1234 — 7.6605 + 152.76; the corresponding values of correlation coefficient and coefficient of curve determination are r = 0.95-H- and R2 = 0.959.
The chestnut blight fungus Cryphonectria parasitica (Murrill) Barr [syn.: Endothia parasitica (Murr) Anderson] caused almost total destruction of the American chestnut (Castanea dentata) and widely spread on European chestnut (Castanea saliva) in many European countries. In Hungary, because this fungus threat...ens most of the Hungarian chestnut stands, great efforts have been made to delay its spread. Biological control with Hungarian hypovirulent strains of the pathogen seems to be an effective method for saving the affected chestnut trees. Until 1998 the fungus was detected on Castanea saliva only, then on some trees of young Quercus petrea in mixed chestnut forests, which also showed the typical symptoms of blight (Kőszeg and Zengővárkony). Although blight symptoms are not so serious in Quercus spp. than in Castanea spp., it seems that C. parasitica threatens the young Quercus spp. in Hungary, mainly in heavily infected chestnut forests. This is the first report of C. parasitica cankers on oak in Hungary.
Isoelectric focusing is an effective and well reproducible method to provide information for identification of various plant species and clones if breeding or other genetic modification(s) for a given species are reflected in changes of an isozyme pattern. The method has been used for characterization of plant proteins and enzymes and for ident...ification of various species and varieties. Our aim was to continue our several-year-work carried out on a wide variety of grapevine varieties and to reveal whether analyses of esterase and peroxidase isozyme patterns are suitable to distinguish various grapevine varieties. Therefore we compared esterase and peroxidase isozyme patterns of various species. Plant samples were obtained from Szigetcsep, Kecskemet, Tokaj and Eger. The following samples were analyzed: Pinot gris, noir, blanc, Chardonnay, Riesling Theses, Chasselas from Szigetcs6p, Bianca and his parents Eger2 and Bouvier from Kecskemet, Furmint and Hárslevelű from Tokaj, Kékfrankos and Zweigelt from Eger. To identify various species according to their esterase isozyme patterns the after blooming phenological phase while according to their peroxidase isozyme pattern the dormant phenological phase was found as optimal sampling time.
Laboratory germination tests have been made with three white fruit pepper varieties and with one spice pepper in filter paper rolls wetted with KCl solutions of different concentration. Parallel tests have been conducted with the other species (lettuce, tomato, kohlrabi) to compare the salt tolerance of paprika with that of other vegetable crop...s.
In greenhouse, the action of KCl has been investigated with transplants raised in soil mixture, in rockwool and with seedlings transplanted from rockwool into soil mixture. Like the trials in the laboratory, the experiments in soil mixture have been made with other plant species, too.
Changes in the dry matter and sugar content occurring during the winter storage of Nantes type carrot hybrids grown on soils of different quality were studied in 199912000 and 200012001. The dry matter content of the varieties tested depended on the production site and on the weather conditions prevailing in the growing season. The increase in...the dry matter content during winter storage reached 6 to 7 per cent in the crop grown in a dry year and 1.5 to 2 per cent in a rainy year. The sugar content was lower in the rainy year (1999) and on brown sand (Szatymaz) than in the rather dry year (2000) and on chernozem soil with residual forest (Tordas), respectively. The increase in sugar content (1 to 5 per cent) measured at the end of storage was related to the season's weather conditions.
Changes in carotene content occurring during winter storage in Nantes type carrot hybrids grown on soils of different quality (sand and loam) have been investigated. The carotene content of the samples grown in a rainy year (1999) was lower than that of the samples grown in a dry year (2000). Lower carotene content was found in carrots produced... on sandy soil (Szatymaz) than on loam soil (Tordas). The increase in carotene content (2-11 mg1100 g) measured at the end of winter storage was related to the season's character.
The influence of antibiotics (cefotaxime, timentin, kanamycin and hygromycin) and growth regulators (indolacetic acid and 6-benzylaminopurine) was evaluated on eggplant organogenesis. Solanum melongena hypocotyl segments (6 to 10 mm length), taken from 16 to 20-days in vitro grown seedlings, were used as explants. The basic medium was...composed by MS salts, Gamborg vitamins and 2% sucrose, solidified with agar 0.8% and pH adjusted to 5.7±0.2. Morphogenesis was impaired at 50 to 100 mg L-I kanamycin and 7.5 mg L-1 hygromycin. Both Timentin and cefotaxime reduced the frequency of regenerating explants meanwhile hyperhydricity was not affected. A decrease in root regeneration was observed with increasing cefotaxime concentrations, although, timentin had no effect on root regeneration, as compared to the control treatment. Interestingly, the number of adventitious roots was more noticeable at 0.25 mg L-I IAA plus 0.5 mg L-1 BAP. However, if just IAA was added led to higher number of regenerated roots compared to other treatments.
The correlation between plant density and yield average shows that the volume of yield increases in varieties of large and medium-size seeds up to a plant density of 285-400 thousand/ha, after which it declines.
On the basis of the results, yield averages at plant densities of 285-334 thousand plant/ha are 0.17 t/ha higher than those ac...hieved at low density (200 thousand plant/ha).
High levels of potassium fertilizer did not enhance the yield of dry beans. With adequate-water supply the high level of potassium decreased the number of pods and seeds per plant compared with a basic level of fertilizer, which could ensure 2.5 t/ha yield.
Two field experiments were carried out in the Experimental Station and Laboratory of the Vegetables and Floriculture Dept., Fac. of Agric., Mansoura Univ., during the winter seasons of 1995/96 and 1996/97. The investigation aimed to study the effect of different sowing dates and NPK fertilization levels, as well as their interactions on active...substances extracted from Isabgol plant (mucilage contents). Four sowing dates and six NPK levels were studied. The main findings in this investigation can be summarized as follows:
- Plants grown in the first sowing data (Nov. 1st week) produced the highest content of mucilage as g/5 g seeds or as percentage of mucilage per plant.
- The addition of NPK fertilization significantly increased the mucilage content of seed and its percentage per plant. The highest content and percentage were in plants treated with the fourth level of NPK (178.0 g/3m2).
- Concerning effect of interaction between sowing dates and NPK levels on mucilage content, the highest content and percentage per plant were produced in plants grown in the first sowing date and treated with the fourth level of NPK.
Broadly the success of genetic transformation of plants requires non-chimeric selection of transformed tissues and its subsequent regeneration. With rare exceptions, most plant transformation protocols still heavily utilize antibiotics for the selection of transgenic cells containing an antibiotic-degrading selectable marker gene. The morphogen...ic capacity of in vitro chrysanthemum and tobacco stem and leaf explants change with the addition of aminoglycoside antibiotics (AAs). Of 6 antibiotics tested, phytotoxicity occurred at 10-25 and 50-100 pgml-I in chrysanthemum and tobacco explants, respectively, depending on the size of the explant and the timing of application. The presence of light or darkness also had a significant effect. The use of transverse thin cell layers (tTCLs) in conjunction with high initial AA selection levels supported the greatest regeneration of transgenic material (adventitious shoots or callus) and the lowest number of escapes. Flow cytometric analyses demonstrate that regeneration can be predicted in both species, depending on the ploidy level of the callus. Endoreduplication was not observed in chrysanthemum, even at high AA levels, but occurred (8C or more) in tobacco callus, even at low AA concentrations (5-10 pgml-1). The higher the AA level, the greater the DNA degradation and the lower the 2C and 4C values.
The global positioning system was made available for public use, which made it possible' to apply a new management tool in agriculture. Precision farming gives much more information on plant-growing than former methods, which makes it possible to use technologies more suitable for micro-sites. It is supposed that more profitable production can...be realised with its aid and the strain on the environment can be reduced, not to mention other economic advantages.
The study makes economic conclusions about the method more and more widely used in plant production taking the yield mapping of Józsefmajor Experimental Farm as a basis and starts ideas about its possible application in arable land olericulture, viticulture and fruit production.
These issues are important because precision farming has existed in glass-culture for a long time from another perspective, which should be spread to open ground horticultural enterprises that are labour and asset intensive, qualitative farming forms with great plantation value.