جستجوی مقالات مرتبط با کلیدواژه « fruit yield » در نشریات گروه « کشاورزی »

Ziziphus mauritiana L., a perennial, evergreen plant from the Rhamnaceae family has 2n=2X=48 chromosomes. It is considered among the plants of tropical and semi-tropical regions, and its geographical distribution includes Abyssinia, North Africa, Arabia, warm parts of Iran and India. The spread of this plant in Iran is mostly in the western and southern regions, including the provinces of Lorestan, Khuzestan, Kerman and Sistan and Baluchistan. Ziziphus mauritiana L., is one of the most resistant fruit trees to harsh environmental conditions, especially drought, dehydration, salinity and high temperature. This plant is well adapted to different environmental conditions and grows from lowlands to heights of a thousand meters above sea level. Jujube (Ziziphus mauritiana L.) is one of the tropical and subtropical fruit trees resistant to rigorous environmental conditions, especially drought, dehydration, salinity and high temperature.

In order to carry out this research, the leaves, fruits and kernels of 14 Ziziphus mauritiana L., genotypes, which were implemented in Minab Agricultural Research Center (located in Hormozgan province) in 2012, in the form of a completely randomized block design with 3 replications, as mother trees supplying grafts were collected and evaluated in University of Zabol in 2016.  Sampling was done in two stages to measure quantitative traits. The first stage took place in the beginning of February 2016 to measure the traits related to the leaves and the second stage after the ripening of the fruit, in late March of the same year, to measure the traits related to the fruit and kernel. The genotypes that were examined in this experiment were named according to the name of each city or village from which they were collected.At the beginning of Bahman, which is the end of the flowering stage of the trees and the beginning of the beginning of closing the fruits, samples of fresh leaves of the trees were randomly taken from the middle parts, in three repetitions and each repetition included 20 samples (from 4 bases and 5 leaves per base). , were collected and during that traits such as leaf length (centimeters), leaf width (centimeters), leaf tail length (centimeters), fresh weight (grams) and leaf dry weight (grams) were measured and recorded. After the physiological ripening of the fruits, in late March (early fruits) to late April (late fruits), the samples were randomly collected in three groups of 10 healthy fruits that were harvested from different parts of the tree, and traits such as Fruit length (cm), fruit width (cm), fruit weight (grams), kernel length (cm), kernel width (cm), kernel thickness (cm), kernel fresh weight (grams), kernel dry weight (grams) , fruit flesh weight (grams) and production rate (kilograms) of each tree were measured.In this research, the morphological traits of leaf, fruit and core of 14 genotypes of jujube (available in south of Iran) has been evaluated using in a Completely random blockdesign with three replications.

Analysis of Variance showed that all the examined traits related to leaves between genotypes had a significant difference at the 1% probability level. Traits such as leaf length, leaf width and leaf tail length showed great variation due to the low coefficient of variation. Simple correlation coefficients revealed that there is a significant correlation between some of the measured traits. Therefore, there is a high correlation between leaf length and leaf width (+0.8), core width with core thickness (+0.87) and fresh leaf weight with fruit rate (-0.43). Considering that the genotypes along the Minab area (22.08) have the highest diversity in the traits, and in among the Minab area, the Talar genotype (18.81) has the highest diversity in the characteristics.In this study, 14 genotypes from different cities of the southern provinces of the country were investigated in the form of a completely randomized block design. After analyzing the data and that the main purpose of measuring the morphological traits was to identify the superior genotype or genotypes in order to use them in breeding programs, therefore some key traits such as leaf length and width, fruit shape, fruit flesh weight and the amount of tree production in Sal, which has the most diversity among the studied genotypes and has the highest percentage of diversity among all the examined traits, and finally understanding such a high diversity will be useful and effective in managing and preserving the germplasm of this plant and with Paying attention to the fact that the genotypes near the Minab region (22.08) have the highest diversity in the evaluated traits and in the Minab region, the Talar genotype (18.81) has the highest diversity in the evaluated characteristics, so it is suggested that in order to create a line or variety To be used in addition to Talar genotype as one of the main bases.

It is suggested that for the creation of the new or top line of jujube have to use the Talar genotype as one of the main foundations.

Tomato (Solanum lycopersicum) is one of the most important economic and widely used crops in horticulture. It is a self-fertilizing and diploid plant and has 24 pairs of chromosomes (2n=2x=24). The life cycle of this plant is one year, and it is cultivated in greenhouses and fields. There are many varieties of tomatoes that differ from each other in terms of plant growth, quality, fruit shape, and other traits. Tomato fruit has a high nutritional value, consisting of minerals, vitamins, fibers, citric acid, β-Carotene and ascorbic acid. Diversity and selection are the two main pillars of any reformation program, and choosing is based on the existence of desirable diversity in the reformation materials under discussion. To produce varieties of tomatoes with high productivity, quality and resistance, breeders need evaluation of genetic diversity, identification and introduction of new genotypes. In other words, systematic study and evaluation of germplasm is of great importance for current and future agronomic and genetic improvement of the crop. Different methods are used to estimate genetic diversity and group genotypes, and the evaluation of morphological and physiological characteristics can be considered as the first step in the investigation of genetic diversity. Different genotypes of tomato differ in terms of morphological and physiological traits, and fruit yield is influenced by some of these traits. Therefore, the selection of criteria other than fruit yield, which have more stability than fruit yield, can be considered as a selection guide in the selection of desirable cultivars. Accordingly, this study was conducted with the aim of investigating the genetic diversity and grouping of tomato genotypes (53 genotypes) based on morphological and physiological traits.

In the present study, 53 genotypes of tomato plants were investigated using a randomized complete block design with three replications under greenhouse conditions at the Gorgan University of Agricultural Sciences and Natural Resources. After disinfecting and planting the seeds in the pot, sampling of the seedlings was performed. Morphological traits such as plant height, stem diameter, fresh and dry weight of the plant, number of side branches, number of leaves, root length, fresh and dry weight of the organ air, fresh and dry weight of roots, fruit number, fruit yield, and physiological traits including proline content, photosynthetic pigments (including chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), and total phenolic and flavonoid compounds were measured. Furthermore, the obtained data were subjected to variance analysis, mean comparison, correlation coefficient, factor analysis, and cluster analysis using suitable software.

After analyzing the data, the results of the evaluation of variance showed that the difference of the studied genotypes in terms of all traits except proline trait was significant at the probability level of 1%. Estimation of the correlation coefficients between the studied traits showed a significant correlation between most of the studied traits and fruit yield. Further, the results of the investigation into factors showed that 6 factors explained more than 77% of the total variance, so that the contribution of the first to sixth factors was 24, 18, 14, 9, 7, and 6% of the total changes, respectively. For better interpretation, larger factor coefficients for each factor were considered significant. Because the largest factor coefficients among the coefficients of each factor indicate the attribute or attribute that plays the greatest role in those factors, the factors were named accordingly. In this way, the first factor was named the fruit yield factor, the second the photosynthesis factor, the third the phenolic factor, the fourth the root weight factor, the fifth the proline factor, and the sixth the stem diameter factor. Based on the results of the cluster analysis, it was observed that the genotypes were significantly different in terms of the measured morphological and physiological traits and they were placed in 3 different groups, each of which had 30, 19, and 4 genotypes, respectively, and the genotypes in the group Third, in terms of studied traits, they were better to other groups.

In general, based on the analysis, the genotypes were significantly different in terms of the measured traits. This article shows that there is a suitable diversity among the studied genotypes and it is possible to select based on these characteristics among the studied genotypes and the selection can be effective in their improvement programs. By estimating the phenotypic correlation coefficients, it was found that the fruit yield trait had the most positive and significant correlation with the number of fruits and the amount of photosynthetic pigments. Therefore, these traits can be considered in tomato fruit yield genetic improvement programs. Considering that the average of most of the traits studied for the genotypes belonging to the third cluster (13, 15, 45 and 46) was higher than the total average and the said genotypes were excellent in terms of developmental and physiological parameters compared with other genotypes, the top genotypes identified in this research can be considered and used in future breeding studies in this valuable plant.

An increase in the temperature and frequent droughts are consequences of the climate change. Using different methods of producing horticultural products in protected ways, such as shading net, is one approach to mitigate the impact of the changing climate. The present study was carried out to determine the effect of shading net on growth and fruit yield and quality of four grapevine (Vitis vinifera) cultivars in the Takestan grapevine research station in 2022. For this purpose, vegetative and reproductive characteristics of four grapevine cultivars (Sahebi, Red Sultana, Red Asgari and Mish Pestan) were evaluated under and outside of green shading net with shade coefficient of 50% as factorial arrangements in randomized complete block design with three replications. Significant increase of internode length under the shading net were recorded. Green shading net significantly increased the titratable acid (80.6%) and the pH of the fruit juice (73.2%), the length and width, and the weight of berry (21.8%, 44.11%, and 41.7%, respectively), cluster length, diameter and weight (51.6%, 49%, and 30.8%, respectively), and fruit yield per vine (65%). However, green shading net caused significant decrease in total soluble solids (17.7%). In all grape cultivars, the total soluble solids under the green shading net was lower than outside the green shading net, and the highest total soluble solids (26 Brix units) belonged to cv. Red Sultana outside of the shading net. The titratable acidity (TA) level of fruit juice under shading net was higher than outside the shading net in all grape cultivars. The highest TA level (8.5g l-1) was observed in cv. Mish Pestan under green shading net. The dimensions of berries under the shading net were greater than outside in all studied grape cultivars. The results showed that the fruit yield and its components increased under green shading net, but fruit ripening prolonged. Therefore, for table grape production, it is necessary to collect the shading net in fruit color changing period to prevent late ripening.

In order to investigate the effect of irrigation intervals, 15 selected Okra genotypes from the National Gene Bank of Iran were cultivated and evaluated in a randomized complete block design with three replications in the 2020-2021 crop year in the experimental research farm of the Seedling and Seed Breeding Research Institute in Karaj (Seed and Plant Improvement Institute).

After the plants entered the three-leaf stage, irrigation was done once every 5 and 10 days.

The results of the analysis of variance showed that the effect of drought stress on all measured traits, including plant height, fruit yield, biological yield, number of ripe fruits, weight of ripe fruit, diameter of ripe fruit, number of seeds per ripe fruit, 1000-seed weight, sugar, and protein content, was statistically significant. Under drought-stress conditions, the mean of all evaluated traits (except soluble sugars) was reduced. The highest fruit yield (12.06 tons per hectare) belonged to genotype 10, which decreased by 37.5% compared to the non-stress conditions of this genotype. Genotypes 1 and 12 had the least change in protein content, genotypes 4 and 6 had the least change in sugar content, and genotypes 9 and 11 had the least change in biological function.

Based on the results obtained from this experiment, the best genotype in terms of fruit yield was genotype 10, and in terms of biological function, genotypes 9 and 11 were recommended for use in areas with water shortages.

Introduction: 

To specify the diversity of pepper plant (Capsicum ssp.) population and the inheritance of fruit characteristics for use in seed production breeding programs, there is a need for a diverse population in terms of the characteristics affecting fruit yield. By a large variety of options available for each product, there is a greater probability of selecting the best decision. A population's genetic variety may be used in several ways, including selection and hybridization. Pepper is a plant belonging to the genus Capsicum and the family Solanaceae. It is cultivated globally, particularly in tropical and subtropical regions. The genus Capsicum contains more than 30 wild and domestic species, which are classified according to flower structure, fruit, and the number of chromosomes (2n= 24, 26). 

Materials and Methods:

 To compare different pepper species based on fruit morphology, a greenhouse experiment was conducted under hydroponic conditions in Zarandieh region, Markazi province, in a completely randomized design with three repetitions in 2021. The seeds of 42 pepper genotypes from 7 species were obtained from Gene Bank of Leibniz Institute of Plant Genetics and Crop Plant Research (IPK). Initially, the seeds were sown in dedicated planting trays. Once the seedlings had grown six leaves, they were transplanted to the main greenhouse. Within the greenhouse, the rows of cultivation were spaced 160 cm apart, with a 25 cm gap between individual plants. Each genotype was represented by ten plants. Throughout the growing season, the plants were managed by maintaining two branches and removing any surplus ones. In this research, the following characteristics were evaluated: fruit production across three harvests, fruit weight, fruit length and diameter, fruit flesh thickness, fruit flavor (spicy or sweet), unripe fruit color, and ripe fruit color. Descriptive statistics of evaluated trait, including mean, minimum and maximum traits and the percentage of phenotypic and genotypic diversity coefficients, heritability, and the analysis of variance and comparison of means, were used to analyze the data.  

Results and Discussion:

 A diverse collection of pepper was evaluated due to the fruit morphological traits and significant differences among different genotypes in terms of these traits. The average fruit weight of the assessed population was 26.54 g. The minimum and maximum fruit weights of 152.70 and 0.13 g were related to genotypes 409 and 276, respectively. Genotype 318, with an average weight of 144.20 g, was not significantly different from genotype 409. Both genotypes were of the species annuum, but were in two separate groups regarding fruit morphology. The heritability rate of fruit weight was 93%, which is consistent with the results of Usman et al. (2014). Length, diameter and length to diameter ratio (fruit morphology index) are the most important factors in marketing pepper fruit. The mean fruit length, diameter and morphology index were 6.35, 2.57 cm and 3.04, respectively. The highest fruit length was related to genotypes 296 and 318 at 26.33, 20.20 and 19 cm, while the lowest fruit length was 0.70, related to genotype 277. The genotypes with the highest lengths were long pepper and Kapia sweet pepper, respectively, and the genotypes with the shortest lengths tasted spicy. Genotypes 409, 200, 318, 326, 272 and 348 had the largest diameter with 6.50, 6.23, 5.80, 5.67, 5.60 and 5.30 cm, respectively. These genotypes are bell, round, Kapia, triangular, triangular, round and sweet in terms of morphology. The smallest fruit diameter belonged to genotype 293 (0.30 cm), and the nineteen genotypes with a diameter of less than 2 cm did not differ significantly from 293. Twenty genotypes with the smallest fruit diameter have a pungent flavor (Table 1). The range of the fruit morphology index was from 0.56 to 8.99. The lowest and highest values were associated with genotypes 342 and 296, respectively (Table 3). The fruit of genotype 296 was sweet, whereas the fruit of genotype 342 was spicy. The heritability of length, diameter and fruit morphology index were 0.97, 0.97 and 0.98%, respectively. The lowest and highest numbers of fruits per plant in each hand-harvest were 1 and 67 fruits, respectively, belonging to genotypes 342 and 326. However, regarding shallow length, diameter, pulp thickness and, consequently, the low weight of the fruit in genotype 342, an almost low yield of this genotype was obtained in three harvests (2742.67 kg/ha). In contrast, genotype 318, despite its small number of fruits per hand-harvest (3 fruits per hand-harvest), had the highest fruit yield of 25379.20 kg Per hectare due to having fruits with large size and pulp thickness and as a result of high fruit weight. The lowest yields related to genotypes 276 and 293 belonged to C. frutescens L., with fruit yields of 17.60 and 44.00 kg/ha in three harvests. However, there was no statistically significant difference among the performance of these genotypes and the genotypes 277, 210, 282, 358, 261, 332, 394, 304, 311, 407, 321, 215, 427, 203, 342 and 200. The percentage of phenotypic and genetic variations in fruit yield was 61, 55% and the heritability of fruit yield was 81%.

This study evaluated a diverse collection of different species of pepper with a wide range of appearance traits. However, the most desirable and marketable characteristics of the fruit were obtained from genotypes belonging to C. annuum. However, genotypes belonging to other species, which were not addressed due to the high number of fruits per plant and resistance to pests and diseases, can play a complementary role in hybrid seed production breeding programs. Based on the results, genotypes 318 (Kapia, yellow and sweet), 287 (long, red and spicy), 348 (round, red and sweet), 272 (triangular, red and sweet), 309 (black, red and sweet) and 296 (long, red and sweet) could be introduced as cultivars after evaluating their compatibility, in terms of their high yield, suitable size fruits and marketability. In addition, because to the substantial variety of the examined population, breeding efforts might develop hybrid cultivars with unique traits.

Pepper is a rich source of essential vitamins and minerals. Like tomatoes, pepper plays an important role in preventing heart diseases due to its high amount of antioxidants. Fruit yield is a complex trait that is not only controlled by several genes, but also greatly influenced by the environment. On the other hand, fruit yield is affected by a large number of other traits and their interaction. Therefore, it is very important for plant breeders to know the relationships between these traits and their interaction effects. The path coefficient analysis is a method that clarifies the relationships between traits and their direct and indirect effects on fruit yield. In this method, the correlation coefficient between two attributes is divided into components that measure direct and indirect effects. Considering the limited studies regarding the evaluation of relationships between fruit yield and other traits affecting fruit yield in pepper, this research was conducted with the aim of identifying these important relationships and evaluating their direct and indirect effects in Iranian pepper populations.
 
In order to carry out this research, the seeds of 30 Iranian pepper accessions were collected directly from the farmers. The experiment was conducted in the form of pot cultivation in the research greenhouse of the Faculty of Agriculture of Urmia University in a completely randomized design with five replications during 2015-2016. After the flowering stage, the desired traits were estimated. Variance analysis was estimated, after examining the basic hypotheses of variance analysis by SAS9.4, as well as the genotypic and phenotypic correlation between traits based on the restricted maximum likelihood (REML) procedure in the SAS9.4 software. Step-by-step regression analysis was used to determine the traits with the most variation justified the fruit yield. The Durbin-Watson test was performed to investigate the independence of experimental errors. Analysis of path coefficients was performed based on the results of stepwise regression and genotypic correlation of traits in the R V.4.0.5.
 
In order to understand the relationships between traits and use them in breeding programs, the phenotypic correlation was estimated.  In this study based on the results of phenotypic correlation, leaf width and leaf length (0.651), single fruit weight and fruit circumference (0.784), fruit circumference and fruit diameter (0.625) and pulp weight and fruit diameter (0.610), showed positive and significant correlation. The purpose of estimating genotypic correlation coefficient is to determine relationships in conditions which in environmental factors are not involved. In the investigation of genotypic correlation, a positive, strong and significant relationship between fruit yield and pulp weight (0.907), fruit circumference (0.891), fruit diameter (0.697), single fruit weight (0.646) and around the plant (0.381) were observed. Given that most of these traits are factors contributing to fruit yield, the presence of such positive and significant genotypic correlation coefficients is reasonable. It can be inferred that pepper accessions with higher fruit characteristics, encompassing factors such as plant density and branching, are likely to exhibit higher fruit yields as well. It's important to note that correlation coefficients are mathematical tools used to measure the linear relationship between two variables. Their significance lies in their mathematical interpretation, and as such, they alone do not provide sufficient proof of a cause-and-effect relationship. Utilizing the results of stepwise regression, less impactful traits or those with minimal effects were eliminated from the model. As a result, seven key traits were identified as the most influential factors affecting fruit yield: pulp weight, plant density, fruit diameter, fruit count, plant height, total seed weight, and branch count.The first characteristic was pulp weight, which was included in the model and explained 78.8% of the fruit yield changes between genotypes. The second characteristic (around the plant) along with pulp weight explained 80.9% of the fruit yield variations. Fruit diameter, together with the previous two characteristics, explained 81.5% of fruit yield variations. In total, the traits included in the model for fruit yield justified 84.6% of the total changes in fruit yield in 30 pepper accessions. In order to better understanding and more accurately interpret of the results, as well as to know the direct and indirect effects and the effect of the traits that were entered into the model through stepwise regression, the path coefficient analysis method was used in this research. Fruit diameter (0.709) and pulp weight (0.289) respectively showed the most positive and direct effect on fruit yield. Fruit pulp weight through fruit diameter had the most positive indirect effect (0.595) on fruit yield. Around the plant showed an indirect positive effect on fruit yield through pulp weight (0.157), fruit diameter (0.392) and number of branches (0.080).
 
In the present study, the trait of fruit diameter had a positive, strong and significant genotypic correlation (0.697) with fruit yield, and it also showed a positive direct effect (0.709) on fruit yield, these two coefficients can be considered equal, Approximately. Therefore, direct selection based on fruit diameter proves to be a valuable strategy for enhancing fruit yield. The magnitude of residual effects serves as an indicator of the model's accuracy in path analysis. When this value is substantial, it may be advisable to incorporate additional causal variables into the model. In the current study, the residual effects value (0.213) affirms the model's optimal accuracy.This research highlights the effectiveness of employing stepwise multivariate regression and path coefficient analysis to gain a deeper understanding of the fundamental relationships between traits. It underscores that relying solely on correlation relationships is insufficient for comprehensively justifying the associations between these traits.

 Grape (Vitis vinifera L.) is one of the most important fruits cultivated in many areas with different climates all over the world. Grape, which is rich in antioxidants, flavonoids, anthocyanins and phenolic acids, is highly regarded in terms of economic value. Salicylic acid is one of the compounds which have been used in recent years for improving the physicochemical properties of many fruits. The application of salicylic acid increases the shelf life of crops by inhibiting ethylene production and respiration, as well as by reducing the activity of some enzymes which are responsible for softening the cell wall. Furthermore, salicylic acid results in the enhancement of phenolic compound production by increasing the activity of some enzymes such as phenylalanine ammonia-lyase.

Materials and Methods:

 The present study was conducted in 2014 on 13-year-old Shahroodi grapes that were grown using a head-training system with a spacing of 2m × 2m in "Shahrood" County, Semnan Province. A total of 60 grapevines with uniform age and growth characteristics were selected for the experiment. Salicylic acid was obtained from Merck and solutions were prepared using a small amount of organic solvent and surfactant to reduce the surface tension of the solutions. For the purpose, the Salicylic acid powder was dissolved in a few drops of ethanol and a few drops of Tween 20 for improving solution penetration to the plants, The solution was prepared at concentrations of 0 (control), 1, 2, 3 mM. Then the plants were sprayed two weeks after the fruit set stage (when berries were at the pea-sized stage with a diameter of 4 to 5 mm). The experimental design used in this experiment was a randomized complete block design (RCBD) with three replications. After harvesting and transporting of fruits to the laboratory, different characteristics were measured:
Chlorophyll and carotenoid Content
Chlorophyll a, b, and total Chlorophyll and carotenoid content measured according to Arnon (1967) method in grape leaves. The extraction steps were carried out with full precision to minimize contact with heat and light. In order to stabilize the pigments, the samples taken from the central part of the mature leaves were immediately ground in liquid nitrogen. The samples were vortexed two times with an interval of one minute and stored for 1.5 hours at a temperature of 4 degrees Celsius in order to dissolve the pigments in cold acetone solvent. After that, they were centrifuged for 15 minutes at a speed of 6000 rpm. The supernatant after centrifugation of the samples was used to measure chlorophyll and total carotenoids. The absorbance of the samples was read at three wavelengths of 470, 645, and 663 nm using a Shimadzu UV (160) spectrophotometer. Using the absorbance of the samples in these three wavelengths and the equations below, the amounts of chlorophyll a, chlorophyll b, total chlorophyll and total carotenoids were calculated in terms of milligrams per gram of tissue sample weight.
Fruit characteristics
 Fruit characteristics such as fruit yield, fruit firmness (with magnets-Taylor device),  sugar and acid content, and content of phenolic compounds were also measured. The fruit tissue firmness was measured using a firmness tester (model FDKA 32, Wagner) and expressed in Newtons per square centimeter. The characteristics of soluble solids (TSS) were expressed using a handheld refractometer (Ataga, Japan) and expressed in terms of Brix, the pH of the extract was measured using a digital pH meter (Sartorius PP-20, Germany). Titratable acidity or TA was done through the titration of the extract using 0.1 normal sodium until pH 1.8-2.8 and its results were reported using the following formula and under the title of tartaric acid percentage.
Total phenol content
 The amount of total phenol was measured by Folin-Ciocalteu method and spectrophotometry. The absorbance of the reaction mixture was measured after 120 minutes of storage in the absence of light at a wavelength of 765 nm using a Shimadzu UV spectrophotometer (160). The amount of total phenol was expressed from the standard curve in terms of mg of gallic acid per 100 grams of extract in three replicates for each sample and standard.
Total flavonoid
 The amount of total flavonoid was measured by aluminum chloride calorimetric method. In this experiment, 50 microliters of methanolic extract from the flesh and fruit skin were combined with 10 microliters of 10% aluminum chloride and 10 microliters of 1 M potassium acetate. Then, 280 microliters of double distilled water were added to the mixture. After the samples were mixed, they were left at room temperature for 40 minutes. The absorbance of the reaction mixture was measured at a wavelength of 415 nm using a Shimadzu UV spectrophotometer (160) in three replicates. A blank containing double distilled water was used for comparison. The amount of total flavonoids was determined based on the standard curve of quercetin and the results were expressed in micrograms of quercetin per gram of fruit skin and flesh weight.
Total anthocyanin
 The amount of total anthocyanin was measured using the difference in pH method. In this method, the absorbance was measured using a spectrophotometer at wavelengths of 520 and 700 nm along with potassium chloride and sodium acetate buffers with different pH values of 1 and 4.5.

 The results of the data analysis of variance showed that the application of salicylic acid resulted in significant differences in the measured characteristics. Therefore, the use of this compound improved the physical and biochemical quality of the treated grape clusters.Comparison of treatments means showed that using 2 mM salicylic acid brought about a significant effect on the amount of chlorophyll (a, b and total) and carotenoids compared to other treatments, especially control. Salicylic acid application caused a reduction in pH and soluble solids, and an increase in firmness, 100-berry weight and yield. The results of the study indicated a significant increase in organic acids and a decrease in reducing sugars in the grape clusters treated with salicylic acid. The highest amount of tartaric acid was found in the treatment with 2 mM salicylic acid, with an average of 0.66, while the control treatment had the lowest amount of tartaric acid, with an average of 0.52. This suggests that the use of salicylic acid led to a reduction in transpiration and consumption of organic acids. In terms of reducing sugars, the highest and lowest amounts were observed in the control treatment (14%/74) and the treatment with 2 mM salicylic acid (13%/60), respectively. Increasing the concentration of salicylic acid up to 2 mM resulted in the enhancement of anthocyanins and phenolic compounds contents, but higher concentrations (more than 2 mM) reduced the amounts of these compounds in treated fruits.

 Pre-harvest use of salicylic acid could have a positive effect on the improvement of qualitative and quantitative characteristics of grape cv. Shahroodi. However, further comprehensive studies are needed to be conducted to recommend this compound to the growers of fruit trees.

Recently, the use bioregulators to ameliorate the effects of environmental stresses on agricultural products has been considered. This split plot experiment was conducted as a randomized complete block design to investigate the moderating effect of some bioregulators on vegetative, biochemical and yield characteristics of greenhouse tomatoes under drought stress in the research greenhouse of University of Hormozgan. Experimental factors were three drought stress levels as the main factor, were include full irrigation as control, moderate and severe drought stress, respectively, irrigation of plants based on providing 100, 75 and 50% readily available water, and foliar application of 0.5 g per plant of biological compounds (the first time one day before applying drought stress and the second time before flowering begins) as a sub-factor including control (without the use of compounds), proline, chitosan and N-Succinyl and N, O dicarboxymethylate chitosan (NSC and NOC, respectively). Application of bioregulators at each water stress level increased the of proline content and catalase and peroxidase enzymes activity in comparison with the control, which in most cases the highest increase in enzyme activity related to NSC. Chitosan derivatives, on the other hand, were able to reduce the amount of malondialdehyde (MDA) and hydrogen peroxide in tomato leaves. Among the biological compounds, NSC and chitosan had the greatest improving effect on the fruit yield via increasing the number and diameter of fruit. So that foliar application with NSC increased fruit yield in control, moderate and severe water stress by 5.33, 17.91 and 33.24%, respectively. Therefore, according to these results, under deficit irrigation conditions, chitosan and its derivatives can reduce the effects of drought stress on tomatoes more efficiently than proline.

Climate changes and agricultural practices such as excessive use of chemical fertilizers and pesticides have intensified the effect of abiotic pressures on crop productivity and have destroyed the ecosystem. One of the strategies to moderate these pressures is the use of organic fertilizers, mycorrhizal symbiosis and microbial inoculation. In order to investigate the effect of organic fertilizer, mycorrhizal fungi and Bacillus on the growth characteristics of bell pepper, an experiment was carried out as split plots on a randomized complete block design with the main factor of organic fertilizer at two levels (with and without organic fertilizer) and the secondary factor of biofertilizer treatments at four levels [arbuscular mycorrhizal (Rhizophagus irregularis + Funeliformis mosseae), Bacillus (B. subtilis + B. amyloliquefaciens)., mycorrhizal + bacteria mixture and control without inoculation] in three replications. Soil biological properties, nutrients uptake and growth characteristics and yield of the fruit were investigated after harvest. The results showed that the organic fertilizer and mycorrhizal fungi application increased the shoot dry weight (10.3% and 17.4%, respectively) and fruit yield (11.5% and 19.9%, respectively) compared to the control. The highest microbial population (1.1 × 107 CFU g-1) and R/S ratio (110.0) were obtained in the organic fertilizer application treatment with mycorrhizal inoculation. Mycorrhizal symbiosis with organic fertilizer application improved the uptake of nitrogen (20.6%), phosphorus (46.8%), iron (35.6%) and zinc (57.2%) compared to the control, and potassium uptake was improved by Bacillus treatment as compared to the control, it increased by 22.3%. In general, the combination of organic fertilizer and mycorrhizal fungi seems to be suitable for greenhouse bell pepper cultivation.

To select the high yielding and adapted pecan genotypes for Dezful climatic conditions in Iran, 50 seedling trees were evaluated in 2019-2021 in Dezful in southwest of Iran. The results showed that P200-7 and P200-8 genotypes had the largest and smallest nuts with 14.3 and 4.2 grams, respectively. P220-2-1 genotype had the highest and P200-9, and P220-2-5 genotypes had the lowest percentage of blank nuts. Kernel removal was easy in P200-1 and P200-10 genotypes, while it was very difficult in P200-3 and P200-31 genotypes. Fruit ripening time was the earliest in P200-1 and P220-2-5 genotypes and the latest in P200-23. P200-23, P220-1-1 and P200-9 genotypes had the highest yield index with 65, 49 and 39 g cm-2 of tree trunk, respectively. The results of evaluation for heat stress tolerance in pecan genotypes showed that 40 to 70% of the branches of all genotypes were damaged by hot temperatures in the summer of 2021 with 430 hours of temperatures above 45 oC, while the branches of P200- 23 genotype were not damaged. In addition, the results indicated that heat stress damage had significant correlation with yield index (r = 0.311*) and kernel color (r = 0.323*). There was highly significant (r = -0.597**) correlation between shell thickness and kernel removal. The relationship between mean fruit weight and nut length (r = 0.386**) and nut width (r = 0.440**) were also highly significant. Factor analysis showed that nut length, shell thickness, blank nuts percentage, nut weight, yield index and heat stress damage accounted for 67% of the total variance. Finally, P200-23 genotype with high yield index, golden bright kernel color and very high heat stress tolerance, and P220-1-1 genotype with high yield and low percentage of blank nuts were identified as promising genotypes for future supplemental research.

In order to study the effect of different chemical and organic fertilizers on the morphological characteristics of physalis an experiment as split plot based on randomized compelet blok design was done in the greenhouse. The main plot includes organic fertilizer at four levels (control, farmyard manure, vermicompost and the combination of farmyard manure and vermicompost) and sub plot included different chemical fertilizers at six levels (control, NPK chemical fertilizer, potash chelate 28%, iron nano chelate 15%, superahyomic and biomass biofertilizer). The results showed that in the culture medium of farmyard manure + vermicompost and with the application of nano-biological biofertilizer, the highest fruit yield per plant (2.29 kg/plant), vitamin C (8.53 mg/g fresh weight), phenol (39.90 mg GA/DW) and total flavonoids (6.89 mg QA/DW), antioxidant properties and soluble solids (16.5 Brix) are obtained in the fruit. The highest and lowest concentrations of nitrogen, phosphorus and potassium of shoots were observed in the treatment of vermicompost + farmyard manure, respectively, along with nano-fertilizer, biofertilizer and control treatments. Considering the favorable effect of vermicompost in the culture medium and biological fertilizers in comparison with the control treatment and chemical fertilizer treatment, it can be considered in the cultivation and feeding programs of physalis in addition to maintaining and improving traits related to growth and yield a healthy product can be offered without chemical fertilizer residues.

A large part of Iran is affected by arid and semi-arid climate and drought has caused many problems in the agricultural sector. The present study aimed to investigate the characteristics of melon under drought stress conditions using manure and bentonite.

This experiment was conducted as a split-factorial based on a randomized complete block design with three replications in Hirmand city during the two cropping years of 2019-2020. Plants irrigated after 25, 50, and 75% of soil moisture depletion which considered as the main plot; and bentonite application (2, 3, and 4 ton/ha); and animal manure (20, 30, and 40 ton/ha) were used as subplots.

According to the results, in the first year of experiment, fruit yield increased by 2.02 times compared to the control under 50% soil moisture depletion with the application of 4 ton/ha of bentonite with 20 ton/ha of animal manure. Also, the leaf area index increased by 5.61 times, and the amount of glucose increased by 2.01 times compared to the control under 25% soil moisture depletion and application of 3 ton/ha of bentonite and 40 ton/ha of animal manure.

To achieve maximum fruit yield, irrigation after 50% soil moisture depletion, application of 4 ton/ha of bentonite, and 20 ton/ha of animal manure for cultivation in the region is recommended.

The study of genetic diversity is an important step in planning crop breeding programs. According to researchers, diversity of the population under selection ensures the desired results in breeding programs. In this regard, using the capacity of local populations to create new cultivars and achieve maximum diversity is very efficient. Therefore, the purpose of this study is to investigate the agro-morphological traits of pepper populations to identify the breeding potential of local populations for producing hybrid cultivars.

In the present study, 30 populations of Iranian peppers were planted in five replications in the research greenhouse of Department of Plant Production and Genetics of Urmia University, in order to study the genetic variability in terms of some agro-morphological traits. The experiment was conducted in a completely randomized design (CRD) in pot conditions in  2016-2017. In this study, variance analysis (ANOVA) and mean comparison of traits by Duncan's multiple range test, estimation of phenotypic correlation by Pearson method and principal component analysis on correlation coefficient and also cluster analysis by Ward method has done and realized. Also, the variance components, heritability (h2), phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), and environmental coefficient of variation (ECV) were calculated.

The results showed significant difference among the populations for all studied traits. The highest phenotypic coefficient of variation (PCV) (88.36) was observed for single fruit weight and also the highest genotypic coefficient of variation (GCV) (83.63) was observed for the same trait (single fruit weight). The pulp weight and fruit yield (0.950) had the highest significant positive correlation coefficient and the single fruit weight and fruit number (-0.558) had the highest significant negative correlation coefficient. According to the results of hierarchical cluster analysis, the studied populations were divided into five clusters based on the studied traits. The Tabriz population in the first cluster and the Gharah Bagh-Urmia population in the fourth cluster were superior in the fruit number trait.

In this study based on the results of mean comparisons Bash Ghala (from Urmia), Nakhchivan (from Urmia) and Keshtiban (from Urmia) populations were superior in terms of most of the studied traits. Also, Bash Ghala (from Urmia), Nakhchivan (from Urmia) and Keshtiban (from Urmia) populations were in the same cluster had higher fruit yield than other studied populations. Therefore, these populations can be used as one of the top parents in the intersection with other populations to create desirable genetic compounds.

This study was conducted to investigate the effects of nitrogen, iron and zinc on the fruit quantity and quality of the 6-years-old sweet lime trees budded on Mexican lime rootstock in the research orchard of Jahrom Islamic Azad University. For this purpose, nitrogen, zinc and iron elements (from sources urea, iron sulfate and zinc sulfate, respectively) were foliar sprayed at concentrations of 0, 3 and 5 g L-1, alone and in combination, before flower induction, in October 2017. The experimental design was factorial based on the randomized complete block design with 27 treatments and three replicates and one sweet lime tree per each replicate performed at two separate locations in the orchard named groups A and B (each group included 81 trees). Based on the results, different amounts of nitrogen, iron and zinc, individually and in combination, had significant effects on all quantitative and qualitative traits of sweet lime fruit atP≤0.05. The effect of location was significant only on the total acids, vitamin C and fruit juice percentage. The highest average fruit weight (228 g) and yield of a single tree (313 kg) was obtained from the combined application of N, Fe and Zn elements at the highest concentration (5 g L-1). The highest TSS and total acid (10.62% and 0.208 mg L-1, respectively) were observed by application of 5 g L-1 Fe without N and Zn, in addition the greatest vitamin C was recorded by application of combined treatment of 3 gL-1 N and Fe and 5 gL-1 Zn with 56.93 mg/100 ml fruit juice.