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Farm-scale evaluation of two widely used sanitation practices for reducing primary inoculums of apple scab in organic apple production
15-18.Views:458Effects of two widely used sanitation practices were evaluated at farm-scale level on leaf degradation and primary infection by Venturia inaequalis in an organic apple orchard (Eperjeske) on two apple cultivars (Jonathan and Prima) from 2011 to 2013. The tested sanitation practices were eradication of fallen leaves by collection and disc cultivation. Treatments of eradication of fallen leaves by collection and disc cultivation reduced signifi cantly (P< 0.001) leaf litter density with 70–85 and 40–55%, respectively, compared to untreated plots in both years. Above treatments in the same order reduced spring scab incidence with 40–50, and 10–20%, respectively, compared to untreated plots. Incidence of leaf scab in autumn was not signifi cantly lower (P< 0.05) in the treatments in the years.
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Comparative anatomical study of leaf tissues of scab resistant and susceptible apple cultivars
43-45.Views:309According to previous studies some anatomical features seem to be connected with resistance or susceptibility to scab caused by Venturia ineaqulis (Cke./Wint.) in case of a given cultivar. Study of leaf anatomy of three scab resistant (‘Prima’, ‘Florina’, MR–12) and two susceptible (‘Watson Jonathan’, ‘Golden Delicious Reinders’) apple cultivars have been made. Preserved preparations made of leaves has been studied by light microscope. Studied parameters were: thickness of leaf blade, thickness of palisade and spongy parenchyma, thickness of epidermal cells, thickness of the cuticle. By measuring leaf thickness and epidermal cell thickness visible differences appeared in certain cultivars, while most conspicuous difference has been shown in thickness of the cuticle.
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Mechanical and physical control in apple orchards as preventative fungal disease management
19-21.Views:529In this minreview, mechanical and physical control against apple fungal diseases among non-chemical control approaches were summarized. This overview listed five groups of mechanical and physical control methods: pruning, removal of inoculum sources, shredding of leaf litter, burying of inoculum sources and flaming of leaf litter. These methods were shown to reduce succesfully infection potential of inoculum sources in orchards and these non-chemical control measures are one of the most essential approaches for preventative fungal disease management. However, most of these methods are not widely spread in the apple-growing practice due to relatively low control efficacy, medium to high labour costs and/or time limits during the season.
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Organic versus integrated apple growing: I. differences in soil and leaf parameters
57-60.Views:1429The aim our study was to establish whether significant differences in nutrients uptake and quality of soil and leaf exist between organic and integrated grown apples. The study was performed at the orchard Fruit Research Station, University of Debrecen, at Debrecen-Pallag during 2002–2004. Macro and micro elements were measured in soil and plant samples. Analyses of variance of soil nitrogen data indicated highly significant differences between the two management systems (P < 0.001) for each examined nitrogen fraction. Analyses of variance of soil phosphate data indicated significant differences (P < 0.05) between the two management systems for orto-PO4 3– contents. Our data indicated that highly significant differences between the two management systems (P < 0.001) for magnesium, copper, and zinc; while significant differences between the two management systems was at P = 0.007 for calcium. Three year’s data of leaf phosphorus, sulphur and zinc were not shown significant differences between production systems. Nevertheless manganese and copper contents of leaves were higher in the organic orchard compared to the integrated one.
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Spectral properties of strawberry plants
17-22.Views:416Strawberry varieties were studied in 3 different growing areas of different soil- and ecological properties in Hungary. We have measured the optical spectra of the leaves together with their nutrient content and performed sensory examinations on the deep frozen and melted fruit. The 6 varieties were Elsanta, Marianna, Spadeka, Symphony, Camarosa, and Raurica. The 3 sites were Újfehértó, Pölöske, and Kecskemet. Colour of the leaves was characterised by their lightness and dominant wavelength. Under non-optimal soil and ecological conditions the varieties could be distinguished by their colour — the leaves became lighter and more yellow. The fruits did not produce the genetically determined taste if the plant can not grow in optimal circumstances — we found a negative correlation between the leaf colour in flowering time and the fruit flavour. Leaf colour measurements performed in flowering time make it possible to improve fruit quality by changing the nutrient supply between flowering and ripening.
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Water use of young apple trees related to leaf area development
61-63.Views:347Present paper describes an investigation concerning seasonal water use and foliage area development of apple trees. Sap flow velocity was measured in the trunks of five years old apple trees cv. `Florina'/M.26 by a thermal dissipation (Granier) method from 20th of May to the end of September in 1998. The development of foliage area was estimated by a method including leaf area measurements, recording of leaves and shoot length. The foliage area reached to 70% of the maximum yearly value at beginning of June. The remaining 30% developed to the end of August. The leaf area specific water use was considerable higher in June and July, than in second part of summer. The trends of ET-FAO and water use curves differed mostly in the late season: the ET-FAO curve falls quite in September compared to August, whereas the value of water use was a similar as in August. This insensitivity of ET-FAO in this period may be a great disadvantage while using the Penman-Monteith equation in irrigation scheduling of apple.
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Cherry leaf spot incidence on 12 sweet cherry cultivars in integrated production
65-67.Views:475The aim of this study was to evaluate the cherry leaf spot (CLS) incidence on 12 sweet cherry cultivars in integrated sweet cherry production in three consecutive years from 2010 till 2012. Assessed cultivars (cvs.) were ’Aida’, ’Axel’, ’Biggareau burlat’, ’Blaze Star’, ’Celeste’, ’Germersdorfi 3’, ’Izabella’, ’Katalin’, ’Krupnoplodnaja’, ’Linda’, ’Sunburst’, ’Vera’Results showed that year had an essential effect on the CLS disease incidence. Cultivars showed great differences within years. Cultivar ’Celeste’ showed the lowest disease incidence on leaves in all years lower than 10%. The largest disease incidence on leaves was on cv. ’Sunburst’ in 2010, on cv. ’Germersdorfi 3’in 2011 and on cv. ’Axel’ in 2012. Disease incidence on these cultivars ranged between 10 and 25%.
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Water consumption of the wine grape varieties Kövidinka K.8 and White Riesling B.7
25-30.Views:223In the Carpathian Basin Kövidinka and White Riesling are promising wine grape varieties. As in the region continental climate dominates and dry years are not uncommon it was natural to study the water requirement and consumption of the two varieties. Morphological characters affecting transpiration were observed including leaf area, hairiness, number and type of stomata. The amount of water transpired per unit leaf area and time and rate of water consumption were measured in a model trial in cuttings with known water supply.
The water consumption of vine cuttings depends on varieties and is determined by the genotype but it is also affected by environment. Kövidinka requires little water and uses it to its advantage White Riesling requires more water and uses it rather lavishly. The results of our model trial could be introduced directly into viticulture practice.
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The effect of Ferbanat L nano-fertilizer on the growing of Petunia x grandiflora ’Musica Blue’
107-109.Views:424During our experiment, the effect of Ferbanat L concentrations were examined by Petunia x grandiflora ‘Musica Blue’ production. The leaf and shoot length, number of flower buds, diameter of flowers, and the date of appearing the first buds were measured. The solution of Ferbanat L in 0.1 % concentration was the most effective on shoot length (21.7 cm). Remarkable increase was observed by the other treatment groups as well comparing to the control group (5.6 cm), the plants treated with solution of Ferbanat L 0.2% (16.5 cm) and 0.3% (14.4 cm) had significant effect as well. The nano-fertilizer had not positive effect on the other examined parameters as leaf and flower size, number of flower buds or chlorophyll content. The culture period shortened five days.
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Rootstock effects on fruit drop and quality of 'Arlet' apples
69-75.Views:791The aim of this study is to investigate the effect of different growth inducing rootstocks on fruit drop of apple. This research was conducted for 3 years at Nagykutas, Western Hungary on apple cv. 'Arlet'. For the experiments, 3 different growth inducing rootstocks were choosen: M.9 (weak), MM.106 (moderate) and crabapple seedling (strong). There were 3 fruit shedding periods on the trees grafted M.9 and MM.106 rootstocks, but in the case of crabapple seedling, only 2 were found. The measure of fruit drop was closely related to seed count of fruits; seed number was the lowest, fruit drop was the highest. The lowest seed number was counted in fruits from trees on crabapple seedling. Seasonal changes of leaf:fruit ratio mainly depended on shoot growth and fruit drop. The rise of the curve of leaf:fruit ratio was very important during the first phase of fruit development, in especially at the end of June and in the beginning of July. The cause of this is that first and second periods of fruit drop appeared during this term. The rise of the curve was important in the beginning of June and the end of July on crabapple seedling. Decreasing tendency of quality parameters was found of fruits from trees on M.9, MM.106 and seedling rootstocks, except flesh firmness which was the highest in fruits from trees on crabapple seedling.
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Anatomical study of the leaves and petioles of scab resistant and susceptible apple cultivars
53-57.Views:305Anatomic studies have been performed on the leaf blade, petiole and annual shoot on six apple cultivars by means of scanning electron as well as light microscope. Four of the cultivars examined are resistant to scab (Florina, Freedom, MR-10, MR-11), whereas two of them are susceptible (Jonathan and Idared). Preliminary results suggest that differences in the width of cross sections of leaf blades, in hairyness, in the shape and size of epidermal cells, moreover, in the cross sections of petioles and shoots are considerable. Some of the anatomical properties seem to be correlated with scab resistance or susceptility of the respective cultivars. Therefore, further studies extending to other cultivars may corroborate our claims to find causal relations between anatomical traits of the leaves and disease, especially scab resistance of apple cultivars.
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The tissue structure of the vegetative organs of strawberry (Fragaria moschata Duch®)
28-31.Views:411The tissue structure of the vegetative organs of strawberry (root, rhizome, stolon, leaf) is discussed in this paper. The authors stated that the root structure described by Muromcev (1969) and Naumann-Seip (1989) develops further from the primary structure. It grows secondarily and the transport tissue becomes continuous having ring shape. In the primary cortex of the rhizome periderm like tissue differentiates, but according to the examinations up to now, it does not take over the role of the exodermis. The exodermis is phloboran filled primary cortex tissue with 3-4 cell rows under the rhizodermis. The development of the transport tissue of the petiole is also a new recognition. In the lower third of the petiole the transport tissue consists of 3 collaterally compound vascular bundles. In the middle third there are 5 bundles because of the separation of the central bundle and in the upper third of the petiole 7 bundles can be observed because of the ramification of the outside bundles. Therefore attention must be taken also in the case of other plants at making sections. There might be confusions in the results of the examinations if the number of bundles increases in the petiole. The tissue structure might vary depending on the origin of the tissue segment.
The palisade parenchyma of the leaf blade has two layers and it is wider than the spongy parenchyma. Among the 5-6-angular cells of the upper epidermis do not develop stomata while in the lower epidermis there are a fairly lot of them.
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Determination of chlorophyll content in case of peach leaf curl disease (Taphrina deformans) with spectral analysis
49-52.Views:812One of the most important conditions of high quality fruit production is the early detection of hytopathologycal infections. The most dangerous disease of peach (Prunus persica) is the Taphrina deformans, which causes serious damages mainly in the years where the weather condition is cool and wet. In this study, healthy and naturally diseased leaves by peach leaf curl were investigated in the laboratory of University of Debrecen, CAAES, Institute of Water and Environmental Management. Both of hyperspectral measurement and the values of spectrophotometer shown the chlorophyll content of diseased leaves were lower than the healthy samples. Based on the experiments the water status of investigated leaves established the infected leaves contained more water in their tissues.
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Physiological and biochemical evolution of peach leaf buds during dormancy course under two contrasted temperature patterns
15-19.Views:200Budbreak 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).
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Some biological properties of new sweet cherry cultivars in Bulgaria and their susceptibility to Blumeriella jaapii
95-97.Views:819Investigations were made on 12 sweet cherry cultivars (‘13-S-22-8’, 'Sunburst', `Kozerska'., 'NY 13791', 'Royalton', 'NY 13688', 'Hartland', `Sumerset', 'Pollax', 'Patriotka Krima', 'Castor', and `Lapins') in an experimental orchard of cherry cultivar collection in the Institute of Agriculture at Kyustendil, Bulgaria during the period of 1997-2003. The trees were planted in 1996. All cultivars were grafted on Prunus mahaleb. Four biological properties of the cultivars were assessed such as blooming time, resistance to late spring frost, fruit ripening and fruit mass. Among cultivars, a good resistance to late spring frost was observed on cultivar 'Sunburst'. The fruit mass varied between 4.2 g (cv. 'Patriotka Krima') and 8.5 g (cv. `Sunburst'). The susceptibility of the cherry cultivars to cherry leaf spot caused by Blumeriella jaapii was assessed in mid-September in each year. The estimation of the rate of attack was made according to the grade of Townsend and Neuberger. All cultivars showed symptoms of cherry leaf spot but the degree of susceptibility was different. Cultivar `Patriotka Krima' was the least susceptible, while cultivar `Somerset' was the most susceptible to Blumeriella jaapii.
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Susceptibility of European pear cultivars to Venturia pirina Aderh. infection at a variety collection in Hungary
41-47.Views:657Field sensitivity of 271 European pear genotypes were evaluated in a large variety collection of pear in Hungary during a nine years survey. Substantial differences were detected in the rate of pear scab infection of leaves and fruits. Some 18 per cent of the inspected genotypes remained completely free of infection even in the years with weather favouring to the disease. On the other hand, 78 % of the inspected genotypes were infected in some or more extent. The rate of infection was generally higher on leaves than on fruits. 18.6 % of the genotypes inspected were tolerant to leaf infection and their majority (81.1 %) were tolerant to fruit infection. Some one fi fth of the genotypes (19.7 %) were highly susceptible to leaf infection but only minor rate of them (2.2 %) were highly susceptible to fruit infection. There were 44 genotypes that could be regarded as tolerant to pear scab leaf and fruit infection under fi eld conditions. Some of these genotypes may be suitable to commercial pear growing with highly reduced chemical control against pear but their yield capacity and fruit quality should be evaluated.
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Rate of scab infection and quality parameters of apple fruit in organic and integrated production systems
63-67.Views:676In this study, the rate of scab infection and quality parameters (content of vitamin-C, dry matter, sugar, total acids, specific weight, quality index and flesh firmness) of some apple cultivars are given, moreover, the relation between those characters was examined in two environmental systems (organic and integrated) in a rainy season. In the organic fruit production, scab infection of leaves was significantly higher than in the integrated system, in case of the same cultivars, which means that the rate of decrease in leaf area was heavier in the organic production. Cultivars did not differ statistically in parameters of inner content when the integrated system was compared to the organic one. Results did not show statistical difference between loss of leaf area caused by apple scab and the parameters of inner content, which is attributed to the regeneration of leaf area due to favourable weather conditions. Data on apple scab and inner content of the fruit justify essentially the environmental systems of apple production.
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Agronomic evaluation of different lettuce (Lactuca sativa L.) varieties under unheated plastic tunnel
50-56.Views:522Among the leafy vegetables, lettuce (Lactuca sativa L.) is the most widely grown species in the world. Wide ranges of physical properties of the products are used to assess the degree of maturity. In this study, different lettuce varieties were grown under an unheated plastic tunnel in springtime. We evaluated the agronomic properties of different lettuce varieties, evaluated the condition of the plants, and determined the bioactive substances. Larger head weight can be achieved by the ‘King of May’ butterhead (259.31 g) and ‘Great Lakes 659’crisphead (220.40 g) genotypes. A very strong correlation (r = 0.995) was observed between the lettuce head index, and leaf index and both had a strong positive correlation (r = 0.828 and 0.760) with NDVI. The highest SPAD values were measured for cos lettuce ‘Romaine lettuce’ (44.01) and iceberg lettuce ‘Great Lakes 659’ (42.71). However, these genotypes showed the highest (9.52%; 8.74%) dry matter content, too. The red leaf variety 'Lollo Rosso' had the highest total polyphenol content (181.53 GAE/100 g FW). Among the evaluated properties, iceberg lettuce showed favorable morphology, plant condition, and good dry matter content. In addition, between the loose-leaf lettuces, the red leaf lollo type was outstanding with bioactive content.
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Some microbial treatments against the tomato leaf miner; Tuta absoluta (Merick) under natural field conditions
81-84.Views:312In an attempt to find more effective methods and safety to control the tomato leaf miner, Tuta absoluta, this research was conducted to study the efficacy of the four bio-treatments ; two bacterial isolates (Bacillus subtilis. and Pseudomonas Fluorescence), one fungal isolate Trichoderma viride) and Spinosad as a microbial insecticide compared with the most common insecticides used against the dipterous and lepidopterous leaf miners in Egypt; Profenofos and Aphox. In the two successive seasons; 2011 and 2012, the fungal isolate Trichoderma viride achieved the lowest infestation(numbers of infested leaflets, mines, infestation percentages) which were 167, 195, and 21.9% resp.in season 2011 and 198, 222 and 26.2% resp. in season 2012. While the highest infestation was occurred in case of using the insecticides, Aphox (423, 559 and 55.9% resp.& 384, 839 and 72.2%. and Prohpenofos (436, 562 and 57.7% &391, 534 and 51.7% resp.).during 2011 and 2012 respectively. The other treatments occupied the intermediate levels. On the other hand, the yield of tomato fruits was increased by 75% over the check in case of plants treated with Trichoderma viride isolate, but the pesticide treatment given weak or no impact in increasing tomato crop. In season 2012, the infested tomato fruits percentages with T. absoluta larvae and Rhizoctonia soil rot disease(that Frequently observed incidentally) were recorded the minimum levels obtained by spraying Trichoderma viride isolate(21.38 and 10.32% resp.). In contrast, the maximum levels were recorded in Prophenofos (44.87 and22.78% resp.) and Aphox treatments(47.22 and 27.78% resp.).
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Disease progress of apple scab caused by Venturia inaequalis in environmentally friendly growing systems
56-62.Views:440Progression 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.
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The effect of 5-aminolevulinic-acid (ALA) on the development of Saintpaulia ionantha
33-36.Views:554In recent work the effect of 5-aminolevulinic-acid (ALA) agent (commercial name Pentakeep-V) was examined on the chlorophyll content, growth and development of Saintpaulia ionantha. The newly re-rooted potted plants were irrigated or sprayed with 0.3‰ or 0.5‰ Pentakeep-V solution, and plus 30% long lasting fertilizer was added to half of the all treatments. Control plants were sprayed with tap water. Best result were obtained on the field of flowering. All the treatments promoted chlorophyll-content in the leaves especially spraying with 0.3‰concentration. Plants treated with Pentakeep-V in both concentrations and independently from the spraying or irrigation flowered more than two weeks earlier than control and those that got plus 30% fertilizer. Besides in the case of some treatments the diameter of leaf rosette, the number and surface size of leaves grew comparing to the control. The longlasting fertilizer had positive effect on the fresh weight but none of treatments had effect on the dry weight.
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Effect of straw and plastic mulches on growth and yield of zero tillage potato (Solanum tuberosum L.) in the Coastal Khulna Region of Bangladesh
23-30.Views:294A randomized complete block design experiment was undertaken at the field laboratory of the Agrotechnology Discipline, Khulna University, Khulna, from November 2021 to March 2022 to ascertain the impact of various mulch treatments on zero tillage potato cultivation. The experiment employed BARI Alu 78 as the planting material and utilized three replications with five distinct mulch treatments. These mulch treatments were identified as follows: Straw mulch (T1), Mulch film (T2), Black polythene (T3), White polythene (T4), and Blue polythene (T5). The metrics that were recorded included the number of sprouts, plant height, number of leaves per plant, leaf width, leaf length, number of tubers, tuber length, tuber breadth, number of defective tubers, weight of defective tubers, and tuber weight. Different mulching techniques significantly influenced the overall crop yield and the underlying factors that influenced the results. The mulch film treatment resulted in the highest yield, with a production of 34.76 tons per hectare, followed by black polythene (28.11 tons per hectare), straw mulch (23.74 tons per hectare), white polythene (20.44 tons per hectare), and blue polythene (18.66 tons per hectare). The economic analysis revealed that mulch film had a high benefit cost ratio along with high input and output. Black polythene came in second place when the benefit cost ratio was compared to that of mulch film and the rest of the three treatments. Combining zero tillage with mulch film or black polythene demonstrates significant potential for becoming a cost-effective practice in the coastal region of Bangladesh.
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Effect of nitrogen on growth and yield of chili (Capsicum annuum var. ‘Marshal’) in Chitwan, Nepal
95-100.Views:475A field experiment was conducted from April to July 2024 in Rampur, Chitwan, to evaluate the performance of different levels of nitrogen on the growth and yield attributes of chili. The Marshal variety of chili was tested under five different nitrogen doses (0, 30, 60, 90, and 120 kg/ha). The treatments were arranged in a one-factorial Randomized Complete Block Design (RCBD) with four replications. Observations were for different growth and yield parameters, and data were analyzed using R-studio. The results revealed that all growth and yield characters of chili were significantly influenced by nitrogen levels. The plants treated with 120 kg/ha nitrogen produced the maximum height (45.6 cm), canopy (604.5 cm2), primary branch (8.67), leaf number (9.78), fruit length (6.26 cm), and fruit weight per plot (111.04 g). The 90 kg/ha nitrogen ranked second, with plant height of 43.12 cm, canopy cover 570.70 cm2, primary branch 7.30, leaf number 9.23, fruit length 5.87 cm, and fruit weight per plot 103.63 g. All parameters were significantly reduced in the control, where no nitrogen was applied. The highest yield was obtained in T5 (3.07 t/ha) followed by T4 (2.98 t/ha), T3 (2.67 t/ha), and T2 (2.32 t/ha). The findings of this study demonstrated that 120 kg/ha nitrogen level resulted in the highest values for all measured traits and was significantly greater than that of all other nitrogen levels. Therefore, it is concluded that nitrogen dose of 120 kg/ha is the most economical for achieving better growth and fruit yield in chili (variety ‘Marshal’).
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Long term investigations of flowers and leaves on mainly non-domestica plums
73-79.Views:336The author dealt with plum species representing different eco-geographic areas by their genetic adaptation and their hybrids, as European (P. domestica, P. italica, P. cerasifera), Asian (P. salicina, P. simonii, P. ussuriensis), American (P. americana, P. besseyi, P. munsoniana, P. tomentosa). The rootstocks of the trees examined were seedlings of C. 679 myrobalan with the exception of Laroda and Santa Rosa II, which were grown on three different stocks: seedlings of C. 174 myrobalan, C. 449 bitter almond and C. 471 sweet almond. The size of peduncle, length of pistil, stamen number per flower, relative stamen number (SN/PL) have been suitable for description and distinction of varieties. Similarly shape of leaves, length of petiole, length and width of blade helped the identification.
The ratio of the dimensions of leaves, length of petiole and of leaf blade, also contributed to the distinction of European, Asian and American plum species, notwithstanding their relations with ecological conditions as well as historical, technical properties, pomological features, etc. Computed indicators (relative stamen number and shape-index of leaves) also have been useful data.
Significant correlations have been found between colour of nectaries and mean values of variety-groups. The potential values of non-European varieties for purposes of commercial production could be forecasted from the point of view of quality, ecological, pomological as well as market value. It is important, however, to know the effect of the rootstock and growing site as well as their interaction, on the one hand, whereas the resistance or tolerance of the varieties as limiting factors, at least to the sharka (Plum pox) virus, Xanthomonas pruni, on the other hand (cf. Surányi & Erdős, 2004a and 2004b).
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The effect of modified bacterial virulence to host-pathogen relationship (Phaseolus vulgaris L. Pseudomonas savastanoi pv. phaseolicola)
53-56.Views:493The Pseudomonas savastanoi pv. phaseolicola is one of the most expressive biogen stressors of the bean (Phaseolus vulgaris L.) in Hungary. The chemical and agrotechnological defence is inefficient, so breeding is the only workable way. The conventional cultivars are susceptible to PS while most of the new industrial varieties have genetic resistance to the pathogen. The genetic background of resistance is, however, a complex system in the bean. Leaf resistance is a monogenic system, but this gene is not expressed in juvenile stage of the host. The pathogen species can be divided into different races. After inoculation with virulent strains, typical symptoms appeared on the leaves. To understand the details of host-pathogen relationships, there were carried out experiments using bacterial strains with altered virulence. Six transposon mutants of the PS were tested. Our main objective was to test these modified bacterial strains on bean cultivars of known genetic background. First we analysed the symptoms, and then the correlation between the symptoms and the multiplication of mutant bacteria. Three cultivars (Cherokee, Inka and Főnix) were tested.
The infection by the virulent PS isolate produced typical symptoms on the three cultivars tested. Mutant bacteria (except strain 756) did not cause any significant symptoms on the hosts. The mutant 756 induced visible symptoms on the cultivars Cherokee and Inka. On Cherokee there were small watersoaked lesions, and HR (hypersensitivity reaction) was detected on Inka, but this was restricted to some cells only (mikro HR). The rate of multiplication of the wild type strain was much higher than the multiplication of the mutants. Bacteria were detected in the cotyledons and primordial leaf, but there is not any substantial number of bacteria in leaves, except for strains 757, 1212 and 1213. The rate of multiplication of strain 756 was intermediate. These, and other experiments can help to understand the genetic background of resistance and the host-pathogen relationship in the Pseudomonas-bean pathosystem.
