مجله تولید و فرآوری محصولات زراعی و باغی
سال چهاردهم شماره 2 (پیاپی 102، تابستان 1403)

Citrus decline is a significant deteriorating factor in citrus cultivation, imposing costly damages to many orchards worldwide, including in Iran. Key factors contributing to citrus decline include environmental stresses such as the physical and chemical conditions of the soil, soil nutritional status, soil moisture condition, and biotic stresses. Environmental stresses, particularly mineral deficiencies and water stress, appear to play a crucial role in citrus deterioration. The Jiroft region is one of the major agricultural centers in south of Iran. Despite its pivotal role in citrus production of the country, the region's orchards experience widespread deterioration, causing considerable annual losses. However, no research has yet explored the potential benefits of simultaneous use of management and nutritional treatments in these orchards.  Therefore, this study aims to investigate the effect of management and nutritional treatments on alleviating both biotic and abiotic stresses and reducing citrus fruit deterioration.

The current study employed a randomized complete block design over two years in Jiroft, south of Iran, incorporating the following treatments: 1. Control: No intervention. 2. Optimal Management: This included timely irrigation, fertilization (chemical and organic amendments based on soil and leaf tests), and gardening practices (pruning, fruit thinning, and weed removal). 3. Optimal Management + Potassium Silicate: This treatment received optimal management plus potassium silicate fertilizer applied through irrigation water three times at a rate of 30 L ha-1 (as determined by soil test). 4. Optimal Management + Shading: This treatment consisted of optimal management with shading (integrated or individual) at approximately 25% during the hot season, along with plant mulch. 5. Optimal Management + Biocontrol & Fungicides/Nematicides: This treatment combined optimal management with Mycorrhizal and Trichoderma fungi, along with fungicides and nematicides. 6. Optimal Management + Calcium Nitrate Injection: Trees received calcium nitrate injection (30%) directly into the trunk twice a year. 7. Optimal Management + Calcium Nitrate Fertilizer & Foliar Spray: This treatment involved optimal management with calcium nitrate fertilizer applied three times (500 grams per tree, one-month intervals) through irrigation water supplemented by foliar sprays containing calcium chelate and micronutrients (zinc, manganese, iron, and copper) applied three times. Then, leaf samples (both 5–6-month-old leaves and new leaves) and fruits were collected and transported to the laboratory for analysis. This analysis included measurements of number of new leaves, leaf area (average surface area per tree leaf), yield, fruit length and diameter, and the concentration of specific macro- and microelements in the leaves.

The results revealed an inverse relationship between the average number of new leaves per tree and the severity of decay. Treatment-4 displayed a 1.5-fold increase in new leaves compared to the control (treatment-1). Additionally, the number of final shoots (spring and summer regrowth) was 191 in the treatment-4 and 76 in the control treatment. In the treatment-4, the mean leaf area was 41.8 cm2, compared to 29.4 cm2 in the control treatment, demonstrating an increase of 42.20%.  Statistical comparisons of other responses also indicated a significant increase in treatment-4 compared to the others. Treatment-4 also exhibited the greatest improvements in fruit size. Fruit diameter and length increased by 35.5% and 33.9%, respectively, compared to the control. Treatment-4 resulted in the largest average leaf area (41.8 cm²) compared to the control (29.4 cm²). Fruit yield followed a similar trend, the lowest fruit yield (22.9 kg/tree) being observed in the control treatment. Conversely, treatment-4 (optimal irrigation management with shading and mulch) achieved the highest fruit yield (50.2 kg/tree), representing a significant increase of 119.2%, 45.9%, 52.5%, 2,100.0%, 95.3%, and 77.4% compared to control, treatment-2, treatment-3, treatment-5, treatment-6, and treatment-7, respectively. Treatment-4 also demonstrated the highest concentrations of zinc, manganese, and iron in the fruits. These elements increased by 1.50, 1.52, and 1.65 times, respectively, compared to the control. The results overwhelmingly favored treatment-4 compared to the control and other treatments. This superiority likely stems from the combined effects of shade mesh and mulch, which are unique to treatment-4. Shade mesh not only provides shade but also reduces radiation intensity, ultimately minimizing heat stress, sunburn, and water loss through evaporation and transpiration from the tree's foliage. Beneficial effects of Treatment-4 go beyond shade and mulch by ensuring optimal plant nutrition based on soil tests, addressing a crucial factor in citrus health. Inadequate nutrition can contribute to tree decline. By providing the necessary macro and micronutrients and adjusting environmental conditions like temperature and humidity, particularly around the roots, we can minimize disruptions in nutrient uptake and promote overall tree health.

Given the warm climatic conditions of Jiroft at Kerman's southern region, citrus decline arises from a combination of biotic and abiotic stresses. Consequently, solutions targeting either biotic or abiotic constraints are unlikely to provide a sustainable solution to the citrus decline question. An integrated approach, incorporating optimal irrigation and combined nutrient management, was found to be more effective. Therefore, implementing optimal irrigation and combined nutrition management, using plant mulch in the shaded area of the trees, and employing netting as a shade was proven to be a suitable solution to the citrus decline in the Jiroft at southern region of Kerman province, Iran.

Alfalfa is one of the most important fodder plants, being able to produce a high quantity of forage dry mass with high concentration of protein and to symbiotically fix atmospheric nitrogen. Having a deep and extensive root system, it reduces soil erosion and improves water penetration in agricultural soils (11). The results of the previous researches showed that the use of Nitroxin and Phosphate Barvar-2 bi-fertilizers had a significant effect on plant protein concentration and the highest protein (22.3%) was obtained when the plants were inoculated with Phosphate Barvar-2 and received organic amendment in the form of mushroom compost. Also, the use of Nitroxin and Barvar-2 bi-fertilizer increased the efficiency of nitrogen consumption, and inoculation with Nitroxin had the highest (22.8%) nitrogen use efficiency (5). Our study aimed to shed light on the nitrogen physiological efficiency and some agronomic traits of alfalfa in the presence of bio-fertilizers and organic manures in Kashan, central Iran.

This study was carried out in Aran and Bidgol, central Iran, in 2014. The experiment was conducted with a factorial arrangement in a randomized complete block design with three replications. Treatments were 4 levels of bio-fertilizers (control, Nitroxin, Phosphate Barvar-2, and Nitroxin+Phosphat Barvar-2) and animal manures (control, cattle manure, sheep manure, and poultry manure in 10 tons/ha). Stems/m2, grains/m2, 1000-grains weight, days to 10 percent flowering, accumulative fresh weight, nitrogen content, protein content, protein yield, physiological efficiency of nitrogen and nitrogen use efficiency were evaluated.

Application of bio-fertilizers enhanced all examined attributes, compared to control, the extent of enhancement in a majority of attributes being greater for Nitroxin + Phosphate Barvar-2. The highest and lowest grains/m2 and 1000-grains weight belonged to application of Nitroxin+ Phosphate Barvar-2 + 10 tons/ha cattle manure and control treatments, respectively. The highest nitrogen content, protein content, and protein yield were obtained by the application of Nitroxin and poultry manures. The highest physiological efficiency of nitrogen was recorded under the conditions of control and cattle manure (3.19 Kg/Kg). The highest nitrogen use efficiency was observed in the presence of cattle manure and Nitroxin+ Phosphate Barvar-2. The application of Nitroxin + Phosphate Barvar-2 with an average of 68.4 tons/ha led to 15.63% increase compared to other levels of bio-fertilizer. Therefore, the combined application of Nitroxin and Phosphate Barvar-2 has been able to produce a high-quality animal feed in successive harvests than the sole application of each of these bio-fertilizers. Among the different levels of organic fertilizers, application of cow manure with an average of 67.08 tons/ha and no use of organic fertilizer with an average of 62.37 tons/ha produced the highest and lowest cumulative fresh weight of alfalfa, respectively. Also, the highest physiological efficiency of nitrogen (with an average of 3.40 kg of grains produced per kg of nitrogen applied) was achieved when 10 tons/ha of cow manure was applied.

The combined application of Nitroxin and Phosphat Barvar-2 bio-fertilizers was more effective than the sole application of each of these biofertilizers. Among the levels of organic manure (10 tons per hectare), cow manure was found to be more effective in enhancing the examined traits. Application of poultry manure had a more favorable effect on nitrogen and protein concentrations and protein yield of alfalfa. Therefore, combined application of Nitroxin and Phosphat Barvar-2 bio-fertilizers is recommended for producing alfalfa in the climatic conditions of Kashan.

Olive (Olea europaea L.) is the most famous species of Oleaceae family that has edible fruits. The olive tree has a tendency to alternate bearing, leading often to the production of massive fruit yield in one year (on) and a very low fruit yield in the next year (off). Knowing the changes of nutrients in different stages of olive fruit growth and development in the “on” and “off” years provides the possibility of timely and correct application of fertilizers. This research was conducted in order to investigate the changes in the concentration of mineral elements, starch, and protein of olive fruit in the on and off-years.

This research was carried out in the years 2018-2019 at Olive Dalaho Research Station in 2018 and 2019 at Dalahu Olive Research Station in Kermanshah (Lat. 32° 30´ N, Long. 45° 51´, Alt. 560 m.), west of Iran. The experiment was carried out in the form of a randomized complete block design with three replications and three local olive varieties, namely Deira, Zagros and Meshkat. All tested 11-year-old trees were under similar conditions in terms of pruning, drip irrigation, fertilization and pest and disease control. Measurement were carried out on N, P, K, Zn, B, starch, and protein in young leaves, fruits, old leaves, and roots from the time of kernel hardening (in early June) until fruit ripening (in mid-November) every 40 days using both "on" and "off" year trees. The samples included 20 broad leaves from the middle part of one-year-old and newly-formed vegetative branches, the growing fruits of the current year, and the feeding roots of 30 cm depth under the canopy of the tree crown. Measurements on potassium concentration were made by a flame photometer (model PFP7 made by JENWAY, England), phosphorus by colorimetric method using spectrophotometer, nitrogen and protein by Kjeldahl method, boron and zinc elements using an atomic absorption device (Perking Elmer model 31/40). Starch concentration of the dry matter was measured by Morley's method.

Monthly changes of mineral elements in leaves and young fruits, starch, and protein concentration in old leaves and roots were significant in the on and off years. The monthly changes in the concentration of the mineral elements corresponded to the pattern of the fruit growth curve (double sigmoid). The concentration of N, K, B, and Zn in young leaves decreased from the beginning of June to the middle of July (the time of endocarp hardening) and then increased slightly. The monthly changes in concentration of mineral elements in leaves and young fruits, starch, and protein in old leaves and roots were significant in the on and off years. The monthly changes of the mineral elements corresponded to the pattern of the fruit growth curve (double sigmoid). The concentration of N, K, B and Zn in young leaves decreased from the beginning of June to the middle of July (the time of endocarp hardening) and then increased slightly. Mashkat cultivar had the highest and Deira and Zagros cultivars had the lowest concentration of nitrogen in young leaves. The concentration of nitrogen has a direct effect on vegetative growth, fruit formation, fruit yield, and shoot growth. There was a positive and significant relationship between fruit nitrogen and phosphorus and zinc concentration of the fruit, but young leaf nitrogen had a negative and significant correlation with phosphorus and zincof the fruit. Deira cultivar had the highest and Meshkat the lowest zinc concentration of the young leaves. Zinc plays a significant role in the function of enzymatic systems, synthesis of nucleic acids, protein and auxin metabolism. There was a positive correlation between phosphorus concentration in young leaves with phosphorus concentration in fruit and leaf starch, but there was a negative correlation with leaf and root protein concentration. The concentration of starch in the old leaves and roots increased and then decreased in the on-year until June. The concentration of root starch decreased slowly from June to November in off-year trees. The concentration of protein in old leaves and roots followed a double sigmoid curve, it decreased sharply until mid-July. From the mid-July to the end of August, the protein concentration of the old leaves slowly and strongly in old leaves and roots, respectively.

Considering the observed changes in the concentration of mineral elements in the leaves and fruits according to the fruit growth pattern, especially in the spring, soil application of nitrogen, phosphorus, and potassium in January (before flowering), foliar spraying of nitrogen, potassium, zinc, and boron in June (after fruit set) and nitrogen and potassium amendments in August (after endocarp hardening) is recommended for the olive orchards of the studied region.

Phaseolus vulgaris L., commonly known as the common bean, is an important legume crop, responsible for 85% of global bean production. Nevertheless, soil salinity represents a significant challenge that severely impairs its productivity. Soil salinity represents one of the most detrimental constraints on crop growth and production. Conversely, beans are regarded as one of the most susceptible crops to salinity stress. However, the detrimental effects of salinity on crops can be significantly mitigated by the use of certain substances. Salinity exerts a significant negative influence on the primary plant processes, including photosynthesis and the production of photoassimilates, which ultimately results in a reduction in plant production. The application of an appropriate quantity of salicylic acid (SA) enhances the plant's tolerance to abiotic stresses, thereby reducing the destructive effects of stress and increasing tolerance to abiotic stresses. It has been demonstrated that the external application of salicylic acid can induce the tolerance of crop plants to a range of abiotic stresses, including salt, drought, heat, cold, and heavy metals. Furthermore, SA can be an effective substance against plant abiotic stresses, as it can regulate a variety of phytohormones, and it may play a key role in free radical scavenging and nutrient uptake. Furthermore, the utilization of biochar represents an efficacious approach to mitigating the consequences of abiotic stresses, such as salinity. Biochar, a carbon-rich material, is employed to enhance soil carbon sequestration, reduce CO₂ emissions, and augment soil microbial diversity and activity. It has been postulated that biochar has the capacity to adsorb some of the toxic ions, such as Na and Cl, thereby reducing the toxic effects of salinity.

A two-year glasshouse study was conducted using a randomized complete block design, with four replicates in each treatment. The study was conducted at the Faculty of Agriculture, University of Mohaghegh Ardabili, Iran over two consecutive years (2022-2023). The experiment included three levels of salicylic acid (SA): SA0 (0 mM), SA0.5 (0.5 mM) and SA1 (1 mM), four levels of biochar, including no biochar application as the control treatment (B0), recommended biochar (Rb) by application of 2.5% biochar. The treatments included 5% (w/w) of modified biochar with phosphoric acid (PA), 1.25% of modified biochar with sulfuric acid (Sb), and salt stress (SS) using NaCl in three levels: SS0 (distilled water), SS4 (4 dS m-1), and SS8 (8 dS m-1). In this experiment, the salinity treatment was applied in two stages: at the planting time and when the seedlings had fully established themselves in the soil. Salicylic acid was applied foliarly at two stages: early and late flowering, according to the predetermined levels.

Salinity had a detrimental impact on the biochemical attributes of bean plants, yet this effect was alleviated by the application of the SA treatment. Furthermore, salt stress resulted in a reduction in relative water content, membrane stability index, leaf area and photosynthetic pigments, which in turn led to a reduction in current photosynthesis and remobilisation of photoassimilates. Nevertheless, the application of biochar and the use of SA were found to alleviate the negative effects, resulting in a higher grain yield compared with the control plants, i.e. at the absence of biochar and SA application at the end of the experiment. The combined application of biochar and SA resulted in a higher relative water content, photosynthetic pigments and an enhanced rate of photosynthesis. The greatest accumulation of chlorophyll-a and carotenoids was observed in response to the application of SA1 without biochar in non-stress conditions. Furthermore, the lowest photosynthetic rate was observed in response to SS8. Moreover, the greatest anthocyanin accumulation was observed in response to the addition of biochar to the soil in the absence of SA under salt stress conditions.
Our research has demonstrated that the combined application of biochar and SA can significantly mitigate the adverse effects of salinity stress on common beans. Furthermore, the results demonstrated that SA significantly enhanced grain yield of plants under both saline and non-saline soils. The results indicate that the excessive use of biochar and SA may lower the mentioned effectiveness, as the biochar increases soil porosity, which negatively impacts water availability. Furthermore, application of high doses of SA has been shown to have a negative impact on the biochemical and enzymatic attributes of the plant under salinity conditions.

Although the study on the effects of biochar and SA on common beans under salinity stress provides valuable insights, it is important to consider the limitations of the study. Consequently, the findings may not be directly extrapolated to the natural agricultural settings, where multiple environmental factors interact.

With the increase in population and improvement in diet diversity, there is a growing need for the quantitative and qualitative development of oil seeds. Camelina (Camelina sativa), an oil seed plant from the Brassicaceae family, is an ideal candidate as it contains 50 to 60% unsaturated fatty acids and omega-3 fatty acids, and has the ability to thrive in adverse environmental conditions. By introducing this new oil plant into cultivation programs, it can significantly contribute to the production of high-quality edible or non-edible oil in the developing countries such as Iran. However, achieving maximum grain yield and appropriate fatty acid composition in camelina oil relies heavily on selecting the appropriate planting date. Additionally, providing necessary nutrients, particularly nitrogen, to the plants is a key aspect of agricultural management to achieve desired quality and quantity of crop products. This research aims to investigate the impact of planting date and different levels of chemical and biological nitrogen fertilizers on the growth characteristics, yield, and oil content of camelina plants in the Eghlid, south of Iran.

This research was conducted in the cropping year of 2021-2022 at the Eghlid Agricultural Research Station in Fars province, south of Iran (Long. 52 42, Lat. 30 55, and Alt. 2375 m above sea level). The experiment was performed as a split-plot design based on a randomized complete block design with three replications. The main plots included different nitrogen fertilizers at four levels: 100% chemical nitrogen (250 kg/ha urea), 75% chemical nitrogen (187 kg/ha urea) + nitrogen biofertilizer, 50% chemical nitrogen (125 kg/ha urea) + nitrogen biofertilizer, and non-use of nitrogen fertilizer (control). The sub-plots included four planting dates: September 11, 2021, September 26, 2021, April 9, 2022, and April 24, 2022. The experimental plots (sub-plots) were determined to be 5 x 2 meters. Each plot consisted of 4 stacks with a distance of 50 cm between them. The distance between sub-plots was 50 cm, the distance between main plots was 150 cm, and the distance between replications (blocks) was 300 cm. On both sides of each stack, seeds were planted in two rows with a distance of 25 cm to achieve a density of 120 plants/m2. One-thirds of the urea nitrogen fertilizer was added to the plots of each treatment before planting, one-thirds at the 6-8 leaf stage, and the remaining third at the stemming stage of camelina. In the biofertilizer treatment, the camelina seeds were inoculated with biofertilizer containing Azotobacter sp. and Azospirillum sp. before being sown. The cumulative growth degree days of seedling emergence, flowering, and ripening, as well as plant height, chlorophyll index, grain yield, yield components and seed oil percentage were evaluated.

With delaying planting from September 11, 2021, to April 24, 2022, the GDD (Growing Degree Days) for camelina emergence decreased, additionally, a delay in planting led to a shorter growth period until full flowering of the camelina plants. Planting in September 26, 2021, led to the longest growth period until full maturity of the camelina plants, while spring planting resulted in a decreased length of the growth period until maturity. The highest plant height (43 cm) was achieved in the presence of 75% chemical fertilizer + biofertilizer nitrogen and the lowest (41 cm) was in the absence of nitrogen fertilizer application. The planting date of September 11, 2021 and April 24, 2022 showed the highest (43 cm) and lowest (37 cm) plant height of camelina. The decrease in plant height during the late planting date was primarily due to the decrease in internode elongation as a result of changes in day length and a shorter vegetative growth period. The highest chlorophyll index (66) was achieved by using 100% nitrogen chemical fertilizer, while the lowest chlorophyll index (52) was observed in the control, lack of fertilizer application. This trait decreased when the planting was delayed. The delay in planting led to a decrease in leaf area, resulting in a decrease in the chlorophyll index during the late planting date. No application of nitrogen fertilizer had the highest seed oil percentage (29.4%), while the application of 75% chemical fertilizer + biofertilizer nitrogen resulted in the lowest oil percentage (18.5%). The delay in planting from early autumn to late spring led to a decrease in the seed oil percentage. This decrease can be attributed to increase in nitrogen content, which promotes the formation of nitrogenous protein precursors. Consequently, more photoassimilates are allocated to protein formation, reducing the available photoassimilates for fatty acid synthesis and, ultimately, limiting oil production capacity. The decrease in oil percentage observed in the most delayed planting dates is likely due to the increase in temperature during the seed filling stage and the reduction in net photosynthesis.
Mean comparison of the interaction between nitrogen fertilizer and planting date on camelina grain yield showed that applying 75% chemical fertilizer + biofertilizer nitrogen, compared to no nitrogen fertilizer, on planting dates of September 11, 2021, September 26, 2021, April 9, 2022, and April 24, 2022, increased grain yield of camelina by 80, 100, 150, and 190 percent, respectively.

The Findings show that in the Eghlid region, autumn-sown camellia out-yields spring-sown one. Additionally, by using a combination of 75% chemical fertilizer and nitrogen biofertilizer, a higher grain yield is achieved compared to using 100% nitrogen chemical fertilizer alone. Considering the importance of production of oilseed plants, like camellia, in Iran and the need for sustainable plant production programs, it appears that growth-promoting bacteria can play a significant role in reducing the need for nitrogen fertilizers.

The Cucurbitaceae family is the second largest horticultural family in terms of economic importance after Solanaceae (1). The genus Cucurbita (2x = 2n = 40), encompasses three economically important crop species such as Cucurbita pepo, Cucurbita moschata, and Cucurbita maxima, cultivated throughout temperate, sub-tropical, and tropical regions (3). Cucurbita pepo L. is the most widely grown and polymorphic of the Cucurbita species (2). Roasted summer squash seeds are used as nut in many cultures worldwide. Production of summer squash in Iran is based on local populations that are combined from several genotypes due to their cross-pollination nature. This lack of uniformity affects both the quantity and quality of squash yield and reduces the marketability of nuts. The purpose of this research was to produce various advanced inbred lines of summer squash by using local germplasm and purifying indigenous populations and also to select superior inbred lines in terms of fruit yield and other desirable agricultural traits that can be used in the production of hybrid cultivars with superior quantity and quality of fruit yield attributes.

In order to preserve internal genetic resources and produce advanced summer squash inbred lines, 83 S6 inbred lines were produced by inducing self-pollination from seven local populations. These genetic resources were obtained by planting the lines twice a year (spring planting at Golestan Agricultural and Natural Resources Research and Education Center and fall planting at Southern Kerman Agricultural and Natural Resources Research and Education Center) from 2018 to 2021. A randomized complete block design with three replications was used to evaluate fruit yield attributes of selected S6 inbred lines and their parental local populations. The following quantitative traits were considered in this study: fruits/plant, fruit weight, fruit length, fruit width, seed yield/m2, seed yield/fruit yield ratio, seed length, seed width, percentage of empty seeds and 1000-seeds weight. Also, Panel test was performed to evaluate the suitability of nuts from a consumer perspective for the following traits: separation of skin from the kernel, taste quality and desirability of seeds shape and size from the consumer's point of view, with six testers. The experimental data were statistically analyzed for variance using the R version 3.5.1. Least significant difference (LSD) test at the probability level of 1% was used to compare the means of each trait. The heat map was created by R version 3.5.1.

The results of analysis of variance at the probability level of 1% indicated that the studied genotypes had significant differences in most of the traits including seed yield/m2, mean of fruits weight, fruits/plant, fruit length, fruit width, seed yield/fruit yield ratio, seed length, seed width, percentage of empty seeds and 1000-seeds weight, taste quality and desirability of seeds shape and size. Based on LSD mean comparison of the traits in selected S6 inbred lines and their parental local populations, the highest seed yield/m2 was observed in line#34 and the highest values of other traits with significant difference were as follows: fruits/plant in line#34, both mean of fruit weight and mean of fruit length in line#248 and line#249, fruit diameter in line#84 and Radkan parental genotype, seed yield/fruit yield ratio in Noodijeh parental genotype, seed length in Noodijeh parental genotype, line#24 and line#32, seed diameter in line#222, 1000-seeds weight in line#249, taste quality in line#224, and desirability of seed shape and size from the consumer's point of view in line#222 and line#34. The results of correlation analysis also showed that the seed yield/m2 had a positive and significant correlation with fruits/plant (r=0.73), but there was no significant relationship with fruit weight. The results suggest that populations with larger fruit weight and size produce fewer fruits; as a result, it reduces the seed yield. In fruits, as the length-to-width ratio increased, there was a trend toward decreased seed number, especially in the peduncular end of the fruit. It seems that breeding and selection for a greater number of small fruits is better than selecting plants with larger fruits. Also, managing agricultural operations, which increase the number of fruits, will increase seed yield/m2.

Based on the results lines #32, 34, 59, 195, 222, 224 and 252 were selected to be used in the breeding programs of cultivar production in future researches. Line#34 can be used as a promising line in compatibility and DUS projects.