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Changes of relative chlorophyll content at maize smut inoculated hybrids
55-58

The leaf chlorophyll content analysis is important for several reasons. The natural or anthropogenic stressors directly effect on the chlorophyll content. Through the measurement of the chlorophyll content it is possible to obtain data concerning the physiological status of the plant, moreover the chlorophyll content is closely related to the nitrogen content, so it is linked to photosynthesis and the photosynthetic activity which determine biomass production.
One of the most common symptoms of plant diseases is the larger and smaller interveinal chlorotic areas. These might be local, or expand to the whole plant. There are multiply reasons of chlorosis such as reduction of chlorophyll content, unfavorable effects on the chlorophyll content,disorders regarding function of chloroplasts or ultimately destruction of the chloroplasts. Although such a chlorotic deviancy can contribute to significant losses in photosynthesis; however the underperformance photosynthesis of the sick plants is a more complex process.
As we unambiguously experienced during our investigations on common smut that the infected maize plants most common accompanying symptom was chlorosis on the leaves, so it is especially important to examine how the infection influenced on the chlorophyll content of different hybrids.

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The impact of climatic factors on the relative chlorophyll content and yield of a maize hybrid in a long-term experiment
71-77

The impact of the climatic factors of crop year on the relative chlorophyll content of maize was examined for three years. The examinations were carried out on the Látókép Experiment Site of the University of Debrecen on calcareous chernozem soil in a small-plot, non-irrigated long-term field experiment with strip plot design. In addition to a non-fertilised (control) treatment, nitrogen (N) fertiliser doses were applied as base and top dressing. The 60 and 120 kg N ha-1 base dressing doses were followed by two top dressing doses at the V6 and V12 phenophases.

Averaged over the different fertiliser treatments, SPAD readings increased in all three years as the growing season progressed. The highes SPAD value increase was observed in the average crop year (2017) at the V12 phenophase (11.8), which further increased at the R1 phenophas, by 3,7. No significant Spad value difference was observed between the average (2017) and the dry year (2018) at the V6 growth phase. However, in the wet crop year (2016), the V690 treatment provided the statistically highest relative chlorophyll content (46.8). At the V12 phenophase, the base dressing dose of 120 kg N ha-1+30 kg N ha-1 (V6150) showed to be successful in two years (2016 and 2018), while in 2017, the base dressing dose of A60 was successful. The impact of crop year on relative chlorophyll content can be clearly shown at the R1 growth stage. In all three years, the significantly highest relative chlorophyll content could be achieved at different nutrient levels: A60 in 2016, V6150 in 2017 and V690.

In a wet year (2016), higher yield could be achieved as a result of the 60 kg N ha-1 base dressing and 30 kg N ha-1 at the V6 growth stage (V690) as top dressing in comparison with 2017 and 2018, when higher fertiliser dose (120 kg N ha-1 base dressing and 30 kg N ha-1top dressing at the V6 growth stage) was needed to achieve a significant yield surplus.

Altogether, averaged over the different treatments, the highest yield (12.48 t ha-1) was observed in the wet year, when the relative chlorophyll content was also the highest (50.6).

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Seasonal changes of photosynthetical parameters as a results of forest gap model
133-136

Photosynthetic parameters of English oak (Quercus robur L.) as a member of Querco robori-Carpinetum were investigated in two different habitat in terms of gap forest management: in the gap and in the host forest. The artifical opening process of the forest resulted in more light for growing saplings and need for acclimatization. Photosynthesis is one of the most important way for plant life and plant production. In the centre of photosynthetic efficiency the quality and quantity traits of photosynthetic pigments are standing. During our work some photosynthetic parameters of plants (in the gap and in the forest as well) were measured: relative chlorophyll content as SPAD index, chlorophyll a and b content, total chlorophyll content and ratio of chlorophyll a and b. Based on our results no significant differences among our data in early spring. Although, during the summer significant differences occurred between the measured values in the gap and in the forest area. Lower total chlorophyll content was experienced in the gap, than in the forest area due to the lower chlorophyll-b content. Because of the high light intensity higher chla/chlb ratio was measured in the gap. The lower chlorophyll contents of gap habitat may have a part of the acclimatization process of photosynthetic apparatus against high light stress, which can determinate the survival chance of individual.

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Evaluation of the correlation between SPAD readings and absolute chlorophyll content of maize under different nitrogen supply conditions
121-126

Currently, one of the most important objectives of agriculture is to maintain the principles of the sustainability. The use of precision technologies in agriculture belongs to this topic. The use of precision technologies is increasingly widespread in the cultivation of various agricultural crops, including maize. Sensing is an important part of these techniques. In our experiment we compared two methods: measuring relative chlorophyll content and the method of determine the extractable chlorophylls. The experimental plant was maize (Zea mays L.) and the measurements were performed at an early development stage (V8) of three genotypes. Three levels of nitrogen (0; 80; 160 kg ha-1) were applied during the experiment. The relative chlorophyll content was measured by SPAD-502 (Minolta, Japan) and a handheld GreenSeeker (Trimble, USA) device. The extractable total chlorophyll content decreased in parallel with the increased nitrogen level. The obtained SPAD values were diversified furthermore the NDVI values have not been changed for the effect of different nitrogen fertilization. In the early stages of development of maize, these parameters need to be complemented with other measurements to provide reliable information about the crops nitrogen status.

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Preliminary studies to evaluate the use of spectral data in monitoring of apple orchard parameters
37-41

The introduction/application of precision agricultural technologies has more important role in various fruit growing sectors among others apple growing. Remote sensing methods can detect electromagnetic waves where the green colour of the leaf is responsible for the chlorophyll content. The absorption of chlorophyll is in the wavelength range of 450–670 nm. Samples of apple tree leaves were taken on a weekly basis from the apple orchard at Horticultural Unit of Pallag on University of Debrecen in 2019 summer. Our studies were performed on 2 cultivars (Early Gold, Golden Reinders) and the samples were processed using 2 methodologies: a non-destructive spectral method and spectrophotometric method chlorophyll and carotenoid contents were calculated, which were created into some groups and compared with the spectral values. When the plant begins to lose strong green colour and turns yellow spectral measurements show that chlorophyll content decreases as the proportion of chlorophyll-carotenoid in the plant changes.  In case of grouping into intervals, it can be observed that as the chlorophyll content increases the reflectance value decreases continuously due to the strong absorption. Based on the results, close relationship between the pigments can be detected.

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Variability examination of photosynthetic pigment content and specific leaf area in individual maize (Zea mays L.) plants
153-157

Currently, maize is one of the most important crops (Zea mays L.) both globally and in Hungary. We compared physiological parameters of a maize genotype – p9903 – at two different experimental sites in a field experiment. Furthermore, we examined these parameters’ variability in individual plants on the leaves with different ages. Absolute chlorophyll content of the leaves were analysed, separately that of chlorophyll a and chlorophyll b. We also measured the absolute carotenoid contents of leaves. Furthermore, we calculated these photosynthetic pigments’ content ratio. Specific leaf area (SLA) and dry matter weight were also measured in order to characterise plant production. The results obviously reflect the decreasing in the efficiency of photosynthetic apparatus on the low yield site. Otherwise, we identify significant differences only in certain cases of leaves.

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Effect of plant growth promoting Rhizobacteria (PGPRS) on yield and quality of processing tomato under water deficiency
19-22

Chlorophyll fluorescence was measured of H1015 tomato hybrid with different bacterial treatments (B0–B1–B2–B3) and three irrigation treatments: regular irrigated (RI), deficit irrigated (DI) and non-irrigated conditions (I0). The aim of the experiments was to show the effects of plant growth promoting rhizobacteria on the yield, dry matter and vitamin C content of processing tomato during different irrigation treatments, and measuring the chlorophyll fluorescence during the ripening and development stages. According to the results, none of the bacterial treatments had a statistical effect on the quantity and quality of the tomato and on the chlorophyll fluorescence, only the irrigation. Further studies are needed.

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The impact of environmental factors on the measurement of the normalized difference vegetation index
141-147

The level of nitrogen supply of a plant population can be quickly measured with non-destructive optical measurement devices and the differentiated determination of nitrogen shortage and the replenishment of nitrogen can also be carried out. The level of nitrogen supply is based on the fact that the chlorophyll content of crops is in close correlation with nitrogen content and that the amount of chlorophyll can be easily measured on the basis of the light absorption of chlorophyll molecules. The successfulness of optical measurements can be influenced by the change of weather  parameters; therefore, it is important to know the correlations between measurement results and weather parameters when it comes to practical use.
The GreenSeeker Model 505 measurement device determines the relative chlorophyll content in the form of the Normalized Difference
Vegetation Index (NDVI) calculated on the basis of the intensity of the reflected red and infrared rays of light from the crop population. The measurements were performed in alfalfa population with 10 replications at five measurement heights and four measurement times. The weather parameters were measured by a weather station located in the middle of the alfalfa population and the correlations between the meteorological data and the NDVI values were examined. During the statistical evaluation of the results, it was established that the NDVI measurement is primarily influenced by the relative humidity of the air, secondly by air temperature and thirdly by wind speed. Relative humidity was in strong correlation with the NDVI values which were also influenced by the measurement height and time. Regression was not significant in the case of 20 cm  measurement height, but the measurements above 40 cm height showed significant correlations. The correlation was shown to be strong at each measurement time, but the influence of humidity was the lowest at 11:00 and 14:00. 

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Correlation analysis of relative chlorophyll content and yield of maize hybrids of different genotypes
211-214

In 2021, correlation between relative chlorophyll content and yield in three maize hybrids of different genotypes was examined. The data were collected at the Látókép Experimental Station of the University of Debrecen located on the Hajdúság loess ridge in Hungary. The soil of the small plot field strip plot trial, which was set up in 2011, was calcareous chernozem. Apart from the control treatment (without fertilisation), N fertiliser is applied in the form of base and top dressing. The base fertiliser containing 60 and 120 kg ha-1 N of nutrient applied in spring was followed by top dressing containing +30–30 kg ha-1 N in V6 and V12 phenophases. SPAD values measured at different phenological stages of the growing season increased by an average of about 28% up to 10 leaf stage for all three hybrids. In the pre-silking period (Vn), the relative chlorophyll content decreased by 8% on average. After an average increase of 14% in the tasselling and silking period, SPAD decreased by an average of about 29% at full maturity (R6).

For the different fertiliser treatments, higher N doses resulted in higher yields. In the basal fertiliser treatment, the A 60 N dose resulted in an average 34% increase in yield, and the A 120 N dose resulted in an average 94% increase in yield compared to the control. The 60 kg ha-1 N basal fertiliser (A60) increased in the V6 phenophase with an additional 30 kg ha-1 N resulted in an average yield increase of 26%. When 120 kg ha-1 N of basal fertiliser (A120) was increased by an additional 30 kg ha-1 N in the V6 phenophase, only the Merida hybrid showed a significant yield increase (7%). No further yield increase was observed when V690 and V6150 treatments were increased by an additional 30 kg ha-1 N in the V12 phenophase. The yield of the Armagnac hybrid decreased by almost 20%, the yield of Fornad by 3% and the yield of Merida by 1%.

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Study of plant physiological parameters in winter oilseed rape (Brassica napus var. napus f. biennis L.) production on chernozem soil
111-115

We made plant physiology examinations in Arkaso winter oilseed rape hybrid substance: relative chlorophyll content (SPAD) and leaf area index (LAI) measurements. The experiment was set in University of Debrecen Agricultural Sciences Center at Látóképi Experimental Station in four replications, in two different sowing times (I. sowing date on 08/22/2014 and II. sowing date on 09/09/2014 sowing againhappened because of the incomplete germination in the second subtance 01/10/2014) Three different plant density 200, 350 and 500 thousand ha-1, under the same nutrient supply, 45 cm row spacing. The experiment was green crop of winter wheat. The relative chlorophyll content (SPAD) and leaf area index (LAI) measurements were made in seven different times. We measured the maximum value of chlorophyll content in the first sowing time at 500, and the second sowing time at 350 thousand ha-1 plant density. The measurement results proved that there was a linear relationship between the number of plants and the LAI. The maximum leaf area index values we measured in both the sowing time at 500 thousand ha-1 reached.

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The effects of water supply on the physiological traits and yield of tomato
25-30

The SPAD value, the chlorophyll fluorescence and the canopy temperature of the leaves and fruits of tomato hybrid “H1015” were investigated under non-irrigated (I0), deficit irrigated (I50) and well-irrigated (I100) conditions. The aim of the experiments was to show which treatment effect on the examined traits affected photosynthesis, leaf temperature and yield quantity, as well as quality under water scarcity. In the control treatment (I0), the canopy temperature increased, but the SPAD decreased compared to the other two treatments (I50 and I100). Chlorophyll fluorescence produced a fluctuating result. In the end, the number of the fruits was high, but the number of the sick and green berries was increased.

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Results of the sensory analysis of precision maize production
59-62

This research was carried out in 2018, at the Látókép Experimental Station of the University of Debrecen in a moderately warm and dry production area, on deep humus layered medium-hard calcareous chernozem soil. In the scope of the research, the chlorophyll content of maize (Zea mays L.) was examined under field circumstances by means of local sensory measurements and we were looking for correlation between the obtained values and the amount of yield. Our measurements were carried out with Minolta SPAD-502 and GreenSeeker devices at 3 measurement times (4 leaf stage, 10 leaf stage and silking). It was found that phenological phases had an effect on the obtained SPAD and NDVI values and were in a slightly significant correlation with the yield. The most significant correlation was found between the results obtained during silking and the amount of yield. This may be because the least time has passed between the measurement time and harvest. Results obtained during the 10-leaf stage show excessive values in each case, which can be due to a measurement error. It was found that the phenological phase had an effect on the correlation of SPAD and NDVI values and the amount of yield. As the phenological phase progressed, the correlation between the measured results and yield has increased.

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Effect of net shading technology on the yield quality and quantity of chilli pepper under greenhouse cultivation
5-9

This study was undertaken to identify the effect of net shading technology on the total capsaicinoids, vitamin C and relative chlorophyll content expressed as SPAD (Soil Plant Analysis Development) values and total marketable fruit yield of ‘Star Flame’ chilli pepper (Capsicum annuum) for two harvesting times cultivated under modified atmosphere. ‘Star Flame’ pepper was grown under three (3) different net shading colours (white, red and green). Samples without net shading were used as control. Samples were subjected to chromatographic analyses using HPLC for the determination of total capsaicinoids and vitamin C. Interaction in shading technology and harvest times (p=0.010) had significant effect on total capsaicinoids as a result of green and white shading technologies showing higher differences when compared to control samples. Vitamin C content was observed to have increased in white and red shadings (p=0.001) after the first harvest and gradually decreased after the second harvesting time (p=0.002). Relative leaf chlorophyll content was significantly higher in white shading in the first and second harvest. Samples used as control had significantly higher marketable values when compared to white and green shadings with red recording low marketability of ‘Star Flame’ chilli peppers.

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The effect of different shading net on the Quantum Efficiency of PS II in chilli pepper cultivar ‘Star Flame’
21-23

The study was undertaken to identify the effect of different shading net on the quantum efficiency of PS II on ‘Star Flame’ chilli pepper (Capsicum annuum) over a period of time cultivated under plastic house environment. ‘Star Flame’ pepper was grown under red shading net and samples without shading were used as control. Analysis of photosynthetic activity revealed a significant difference (p<0.05) between Fv/Fm values in control and red shading at the end of July (p = 0.031) after the first harvest. Chlorophyll fluorescence parameter Fv/Fm reflects the maximum quantum efficiency of photosystem II (PS II) used in the detection of early stress in plants.

 

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Examination of Zn deficiency on some physiological parameters in case of maize and cucumber seedlings
5-9

Zinc (Zn) is an essential micronutrient needed not only for people, but also crops. Almost half of the world’s cereal crops are deficient in
Zn, leading to poor crop yields. In fact, one-third (33%) of the world's population is at risk of Zn deficiency in rates, ranging from 4% to
73% depending on the given country. Zn deficiency in agricultural soils is also a major global problem affecting both crop yield and quality.
The Zn contents of soils in Hungary are medium or rather small. Generally, the rate of Zn deficiency is higher on sand, sandy loam or soil
types of large organic matter contents. High pH and calcium carbonate contents are the main reasons for the low availability of Zn for
plants (Karimian and Moafpouryan, 1999). It has been reported that the high-concentration application of phosphate fertilisers reduces Zn
availability (Khosgoftarmanesh et al., 2006). Areas with Zn deficiency are particularly extensive in Békés, Fejér and Tolna County in
Hungary, yet these areas feature topsoils of high organic matter contents. Usually, Zn is absorbed strongly in the upper part the soil, and it
has been observed that the uptakeable Zn contents of soil are lower than 1.4 mg kg-1.
Maize is one of the most important crops in Hungary, grown in the largest areas, and belongs to the most sensitive cultures to Zn
deficiency. Zn deficiency can causes serious damage in yield (as large as 80 %), especially in case of maize. On the other hand, Zn
deficiency can also cause serious reduction in the yields of dicots. One of the most important vegetables of canning industry is cucumber,
which is grown all over the world.
In this study, the effects of Zn deficiency have investigated on the growth of shoots and roots, relative and absolute chlorophyll contents,
fresh and dry matter accumulation, total root and shoot lengths, the leaf number and leaf area of test plants in laboratory. Experimental
plants used have been maize (Zea mays L. cv. Reseda sc.) and cucumber (Cucumis sativus L. cv. Delicatess). A monocot and dicot plant have
chosen a to investigate the effects of Zn deficiency, because they have different nutrient uptake mechanism.
It has been observed that the unfavourable effects of Zn deficiency have caused damage in some physiological parameters, and
significantly reduced the growth, chlorophyll contents of monocots and dicots alike.

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Using sensors in precision crop production
267-270

Proper plant nutrition that takes into consideration both the requirements of plants and ecological conditions is one of the most important precondition of successful plant production. An important element of the N-fertilization of wheat is that the optimum zone of nitrogen supply is significantly narrower than that of other plant species, therefore it can easily happen that we apply higher or lower nitrogen doses than the optimal one. A possible solution to this problem can be precision agriculture. Applying the methods of precision agriculture we can take into consideration the heterogeneity of fields. By applying precision methods either online or offline we can intervene faster than if we would rely only on regular soil and plant analysis procedures. The determination of the doses of nitrogen and the timing of application are influenced also environmental and
economic aspects. The chlorophyll content of the leaves indicates the nitrogen status of plants, since there is a relationship between the nitrogen content and the amount of chlorophyll in the leaves. According to plant analysis results there was a strong and significant relationship between the values of the NDVI (Normalized Difference Vegetation Index)and the total nitrogen content measured in the leaves.

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The Effect of Smut Gall Tumour Infection on Iron and Zinc Uptake and Distribution in Maize Seedlings
27-32

The amounts of Fe, and Zn were measured in maize seedlings infected by smut gall tumour (Ustilago maydis Dc. Cda.) and in healthy seedlings five days after infection. The amount of elements was also measured under different stress intensities. Due to the infection, as a biotic stress, the amount and distribution of examined elements have been changed. On the bases of the differences in the Fe distribution between the symptoms less and tumorial leaf parts, we have come to the conclusion that the infection also effects the mobilisation of Fe and Zn inside the plants. The Fe uptake was much higher in the infected plants and the tumour development also had an effect on the uptake and distribution of the examined elements. The experiments of infecting maize seedlings by monosporidial strain of crown gall tumour showed no tumour development. We found that the monosporidial strain also acts as a biotic stress and has an effect of iron and zinc distribution. We observed a slight difference in the iron and zinc contents in the roots of corn seedlings infected by different monosporidial sporidium concentrations, while the iron and zinc contents in the shoots were increased by the intensity of the infection. The roots do not form tumours. There is no difference between the roots of the infected and healthy corn seedlings. Since the Fe and Zn contents of the shoots of infected plants depend on the intensity of the infection, we have come to the conclusion that there must exist a „special” communication system regulating the transportation of the examined elements.
In the experiments with infected maize seedlings, it became necessary to get the iron chlorosis before the disease reaches the lethal phase. Although most of the iron reserves are located in the embryo, to accelerate the chlorosis, the endosperm was removed, and it was observed, that the iron chlorosis appears later in maize seedlings when the endosperm is removed. The relative chlorophyll content of the first and second leaves was measured in iron efficient and iron deficient maize seedlings at different times.
The higher IAA content of tumorial plant tissues is already known. The treatment with IAA decreases the iron concentration in the shoots and in the roots of +Fe precultured plants and increases at -Fe precultured ones. The TIBA retards the shoot-to-root transport of IAA. When the seedlings were treated simultaneously with IAA and TIBA, higher iron concentrations were observed in the shoots and in the roots of corn seedlings.
We found extremely high iron concentrations in the roots of infected seedlings and, in line with this, serious damage to the roots was observed that this can be caused by the high iron content generated free radicals. The results demonstrate that IAA has a role in the shoot to root communication.

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Examination of the chlorophyll content of maize hybrids of different maturity groups at different N fertiliser doses
159-162

Nitrogen fertilisation is a critical point of maize production. Five hybrids of different maturity dates were examined in a field experiment, three treatments (different application dates) and three basic fertiliser doses (0, 60, 120 kg ha-1 N) were used. At the 6-leaf-stage of maize, each fertilisation level of the 2nd and 3rd treatment was given 30 kg N ha-1 fertiliser active ingredient in addition to the basic fertiliser doses with the exception of the control plots and further 30 kg N ha-1 fertiliser was applied at the 12-leaf-stage. The final fertiliser doses were 0, 90 and 150 kg N ha-1 in the second treatment and 0, 120 and 180 kg N ha-1 in the 3rd treatment. The whole amount of the basic fertiliser (ammonium nitrate) was applied in the spring, one month before sowing.

The relative chlorophyll content of the maize leaves was measured, with a Minolta SPAD-502 measurement device. The measurements were carried out at the 6-leaf growth stage (V6) of maize on the youngest fully developed leaf of the 6th, 7th and 8th plants from the second row of each plot.

There were significant differences in the SPAD-readings measured at the V6 phenophase of maize between the hybrids (p<0.001) and the fertiliser treatments (p<0.05). The regression analysis did not show any correlation between the SPAD-values and fertilisation.

The highest significant SPAD-reading and yield were obtained by applying 120 kg ha-1 N. As a result of the regression analysis performed on yield, it can be concluded that the correlation between fertilisation and yield in the 1st and 2nd treatment was moderately close (r=0.439, r=0.480) and it was close in the 3rd treatment (r=0.513). The correlation between the SPAD-readings and yield was the closes in the 2nd treatment (r=0.639), while the SPAD-value had a 40.9% influence on yield (p<0.001).

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Physiological traits and yield of three soybean (Glycine max (L.) Merr.) genotypes as affected by water deficiency
11-15

Soybean is a very important legume; it has the highest protein content, and it is a very important source of vegetable oil. Soybean is droughtsusceptible, and drought is one of the major abiotic stresses that has been increasing over the past decades as a result of the global climatic changes. To evaluate the influence of drought stress, three soybean genotypes were grown under rainfed conditions, and compared to irrigated controls. The obtained results showed that the chlorophyll content, leaf area index and plant height decreased under drought stress conditions, which led to noticeable and sometimes significant yield reduction. Our results suggest more specific studies on the physiological changes of the local soybean genotypes under drought stress to better select the adopted ones.

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The impact of cultivar and irrigation on yield, leaf surface temperature and SPAD readings of chili pepper
103-108

Paprika is an extremely popular and widespread plant species in Hungary. Chili peppers belongs to paprika and it can be consumed fresh or processed. The production of peppers began with the cultivation and control of some parameters for good results of paprika production. The aim of this article is to compare the water supply of four chili pepper hybrids ("Habanero", "Hetényi Parázs", "Unikal" and "Unijol") by means of investigation on open field and to examine how different temperatures and water stress factors influence the yield of chili peppers. The experiment area consisted of four different hybrids in three different irrigation treatments (control, deficit- and regular irrigation). The chlorophyll content was estimated with SPAD and the leaf surface temperature with Raytek MX4 TD. Our research concluded that deficit irrigation produced the highest yields for all cultivars and the lowest yields for the highest water supply.

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Effect of arginine, putrescine and spermidine on the polyamine, proline and chlorophyll content of tobacco (Nicotiana tabacum L.)
39-43

Polyamines, such as spermidine (Spd) spermine (Spm) and their direct precursor, the diamine putrescine (Put) are vital and essential aliphatic amines which are also present in plants. Although ethylene and polyamines are also involved in fruit ripening, the genes coding them must also take part in other biosynthetic pathways. In the ethylene and polyamines play an important role in development of salt stress tolerance, and in responses for biotic and abiotic stresses. Exogenous application of all three main polyamines (Put, Spd, Spm) increase salt tolerance of plants, but, accordingly to previous experiments, spermidine has the main effect on the enhancement of salt tolerance. Nicotiana tabacum L. plants were grown in vitro on MS medium, the treatments were as follows: arginine (150 mg l-1), putrescine (10 mg l-1), spermidine (10
mg l-1). Proline, chlorophyll a, b and polyamine contents were measured. The obtained results show that the arginine decarboxylase and the spermidine synthase genes involved in polyamine metabolism, cannot be enhanced by exogenous addition of their precursor molecules. On the contrary, the spermine synthase gene has a positive effect to the lower-class forms of polyamines.

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The impact of applying foliar fertilizers on the health condition of maize
105-109

 

The nutrient supply of plants is becoming more important in plant protection since the appropriate condition of plants can be ensured by optimal and satisfactory nutrient supply to avoid nutritional deficiency diseases. Due to the extreme weather conditions, plants are forced to face several stress factors, which leads to deterioration of the plant health. The increasing occurrence of droughts poses threat to nutrient uptake through the roots since all the nutrients can be accessible to the plants only if they are in dissolved form in the soil – which is not possible in the absence of water. Therefore, the importance of foliar fertilizer is becoming a more and more significant part of the nutrient supply, because with the help of this technology the development of any nutrient deficiency can be prevented.

In this experiment, we focused on the efficiency of two different foliar fertilizers on maize.  Foliar fertilizers were applied two times, once in the stage with 8 leaves and tasseling phenophase of the maize. To verify the efficiency of the foliar fertilizers, the chlorophyll content of untreated and treated plant’s leaves was measured after each application. Moreover, the length and diameter of maize cobs, thousand kernel weight, protein, oil and starch content were also measured, and the results were compared to the untreated (control) ones. According to the results, in all aspects significant differences were observed and due to the laboratory analysis of leaves, in the case of magnesium and zinc supply the foliar fertilizers were able to prevent the development of nutrient deficiency.

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Study of some physiologic properties of different genotype sweet corn hybrids
105-110

The effect of nutrient-supply (control, N120+PK) and two different genotypes on the physiologic properties of sweet corn has been investigated in the crop-year of 2011 on chernozem soil in the Hajdúság region. The experiments were carried out at the Experimental Station of the University of Debrecen in Debrecen-Látókép. The experiment was sewn in two different sowing times: the 21st April can be considered as an early, while the 19th May as a late sowing time. The two involved hybrids were Jumbo and Enterprise. The applied plant density was 65 000 plants per hectare.
Our aim with this experiment was to study the plant production, just as the main affecting factors of its development and dynamics, like nutrient-supply and genotypes. We aimed to study and analyse the relationships between these factors and plant production. In this study following parameters were measured and calculated: photosynthetic activity, chlorophyll-content (SPAD-value), leaf area index (LAI) and leaf area duration (LAD). Regarding the analysis of photosynthetic activity values no obvious relationship between the measured values and the applied hybrids, just as nutrient-supply has been revealed. 
Analysing the SPAD-values it can be stated that the chlorophyll-content of the measured leaves showed an increasing tendency due to the nutrient-supply. The highest values have been measured in the intensive cob development phase of the early sowing time plots.
Regarding the LAI-values we have found significant differences between the fertilizer treatments in both sowing time treatments. In case of the leaf area duration values – that is derived from the LAI values – nutrient-supply has positively affected the duration of the assimilation area.

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Water relations composition among Egyptian cotton genotypes under water deficit
5-15

Background: water shortage is one of the major factor effects on growth characters and yield of most crops. Objective: this study was conducted to get to know the reactions of some Egyptian cotton genotypes to water deficit. Methods: The genetic materials used in this study included thirteen cotton genotypes belonging to Gossypium barbadense L., from the Cotton Research Institute (CRI), which was devoted to establishing the experimental materials for this investigation. Results: the ratio of GCA/SCA was less than unity for all studied indices, indicating predominance of non-additive gene action (dominance and epistasis), which is an important in exploitation of heterosis through hybrid breeding. Results: The data showed significant reduction in water relationship characters for all parental genotypes under stress conditions. The Egyptian variety Giza 68 gave high values for most water relationship characters. Data revealed that the greater the value of tolerance index is, the larger the yield reduction is under water deficit conditions and the higher the stress sensitivity is becoming. The parental genotypes Giza 96 showed the highest reduction in yield under water deficit conditions. At the same time, the cross combination Minufy x Australy showed higher values of yield reduction followed by the combinations Giza 67 x Australy. Of the male parents, the Russian genotype 10229 recorded the best GCA values for most water relationship characters. At the same time, the female parents, the old Egyptian genotype Giza 67 recorded the best values and exhibited good general combined for most water relationship characters. The cross combinations Giza 86 x Pima S6, Giza 77 x Pima S6, Giza 94 x Dandra and Giza 96 x Australy showed significant desirable SCA effect for most characters. Conclusion: relative water content %, osmotic pressure, chlorophyll and carotenoids content indicates better availability of water in the cell, which increases the photosynthetic rate. Also, the higher level of proline accumulation in the leaves which was recorded under deficit water suggests that the production of proline is probably a common response of plant under water deficit conditions.

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Response of maize seedlings to the latent zinc deficiency under different Fe/Zn rati
125-128

Zinc (Zn) deficiency is a critical nutritional problem for plants and peoples all over the world. Almost half of the world’s cereal crops are deficient in Zn, leading to poor crop yield. In this study, the effect of different Fe/Zn ratio on some physiological parameters of maize seedlings were investigated on the dry matter of shoots and roots and their ratio, SPAD index and the total length of shoots. The relative chlorophyll contents significantly decreased under increasing Fe given to the Zn deficient. The results showed that the different Fe/Zn supplies decreased the total length of shoots - ranging from 9% to 65% - by latent Zn deficiency. Corresponding to several scientific findings, it was observed that the non-optimal Fe/Zn ratio of tissues take part in the evolution of latent Zn deficiency in the case of high Fe concentration.

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