فصلنامه پژوهش های تولید گیاهی
سال بیست و نهم شماره 1 (بهار 1401)

In kiwifruiy vineyards, the high concentration of bicarbonate ions in irrigation water or soil is one of the main limiting factors on growth and production. The high levels of bicarbonate in irrigation water caused soil alkalinity and reduced the root accessibility to nutrients such as irons. Iron deficiency in kiwifruit vineyards caused leaves chlorosis and therafter, fruits. Fruits with iron deficiency have an unacceptable taste and low shelf life. Iron deficiency is usually more severe in June and July with increasing irrigation frequency. Growing suitable rootstocks that have a high tolerance to soil alkalinity is a good strategy to overcome this problem. Therefore, in this study, the response of seedlings in different populations of kiwifruit from three different species to irrigation water bicarbonate was investigated.

In this study, the effect of different concentrations of bicarbonate ions in irrigation water (0, 170, 350, and 550 mg L-1) on leaf chlorosis and iron uptake of seedlings of six kiwifruit seed populations (Green 11, Bruno, Red 2, Red 6, Red 22 and Baby kiwi) from three different species (Actinidia deliciosa, A. chinensis and A. arguta) was investigated as a factorial experiment in a completely randomized design with three replications in research greenhouse of faculty of agricultural sciences, University of guilan. Each replication was one potted seedling. The plants were irrigated with different bicarbonate level for 6 weeks with three days intaervals. Traits such as leaf fall percentage, stem diameter, chlorosis percentage, necrosis percentage, chlorophyll a, b, total chlorophyll, carotenoids and iron content of leaves were measured.

The results showed that increasing bicarbonate concentration in irrigation water caused leaf abscission. The highest leaf abscission percentage was observed in Baby kiwi from A. arguta with 16.6% and the lowest one in Bruno (1.19%) from A. deliciosa species as compared to their control, when exposed to high bicarbonate stress. Genotype type, different levels of bicarbonate and their interaction did not show a significant effect on the percentage of stem diameter changes. The Red2 from A. chinensis species seedlings showed the highest leaf chlorosis (38.46%) and the lowest leaf chlorosis was found in Green 11 seedlings from A. deliciosa with 6.95%. With increasing the amount of bicarbonate in irrigation water, the percentage of leaf necrosis also increased. Total leaf chlorophyll and carotenoid content significantly declined in all genotypes with increasing bicarbonate ion content in irrigation water. With increasing bicarbonate ion concentration in irrigation water, leaf iron content significantly decreased. The lowest iron declining percentage compared to the control when seedlings exposed to 170, 350, and 550 (mg L-1) of bicarbonate of irrigation water was found in Bruno from A. deliciosa species with 3.28, 4.29, and 4.72%, respectively. Moreover, the results showed that there is a significant correlation between leaf iron content and chlorophylls content, chlorosis percentage and necrosis percentage.

Overall, because of low leaf abscission and higher iron absorption in Bruno seedlings when exposed to high bicarbonate concentration in irrigation water or soil cab be recommend as a souperior rootstock.

Nowadays, concerns about the amount of carbon emission to atmosphere and its effects on the climate are increasing. In the new approach to agricultural ecosystem management, carbon sequestration service is being replaced by carbon emissions. Therefore, providing accurate information on the spatial distribution of biomass and carbon sequestration potential of ecosystems is an essential issue. The purpose of this study was to using vegetation index to estimate the potential of carbon sequestration in soybean (Glycine max L.) biomass in the fields of Gorgan county.

This study was conducted in soybean fields of Gorgan county, located in Golestan province during 2016-2017. In order to carry out this study, we were used satellite images of Sentinel 2 on 17.9.2017. Also, the accuracy of the images was checked after geometric and radiometric corrections using 250 ground control points. In the field section, plant samples from of 150 points were randomly prepared using 0.5 × 0.5 quadrats in the stage of maximum vegetative growth of soybean and transferred to the agricultural research laboratory of Gorgan University of Agricultural Sciences and Natural Resources. Then, the dry weight of plant samples was calculated and the amount of carbon in the plant biomass (stems and leaves) was determined using the combustion method. To prepare the land use map of soybean cultivation area, the supervised classification was used according to the maximum and minimum reliability algorithm. The accuracy of this classification was assessed by value of overall accuracy and Kappa coefficient. The studied vegetation indices were NDVI (Normalized Difference Vegetation Index), DVI (Deference Vegetation Index), RVI (Ratio Vegetation Index) and SAVI (Soil Adjusted Vegetation index). Then, a regression relationship was established between plant indices and biomass and carbon sequestration potential in SPSS 16 software. After selecting the best vegetation index, plant biomass and carbon sequestration potential maps were prepared using ArcGIS 10.6 software. Then, using classification methods, the final layer was divided into four classes of biomass and carbon sequestration potential.

In this study, the area of soybean cultivation in Gorgan county was estimated as 12333.71 hectares. The results showed that the value of overall accuracy coefficient in the classification method was the minimum distance from the mean, 87% and in the maximum probability method was 92% and the value of Kappa coefficient was 0.79 and 0.93, respectively. Based on the results of regression analysis, DVI index was selected for biomass mapping and carbon sequestration potential due to the highest coefficient of determination (0.86) and the lowest amount of RMSE. Based on the results, the highest amount of carbon sequestration potential was obtained from 1924.78 to 2526.18 kg.ha-1 in the central and eastern parts of this region, and the lowest value estimated as 919.43 to 1313.83 kg.ha-1 that related to western regions of Gorgan.

In this experiment, DVI index indicated a better estimation of carbon sequestration potential in soybean agroecosystems. Due to the high accuracy, easiness and low cost of remote sensing technology, especially calculation of vegetation indices, this approach can used to estimate the biomass and carbon sequestration potential of crops in agroecosystems.

Satureja rechingeri Jamzad, a member of the Lamiaceae family, is a species endemic to Iran, which has a wide distribution in southern Iran (mainly Khuzestan and Ilam). This plant has many medicinal properties and the main composition of its essential oil is carvacrol (48 to 95%). Carvacrol is mainly involved in biological activities and used in the production of substances such as antibiotics and antioxidants. Drought and salinity stress are the main limiting factors for successful production and yield of crops in Iran and the world. Salinity alters metabolic processes and the activity of enzymes. One of the biochemical changes that occur in plants when exposed to saline environments is the increase in the production of oxygen free radicals. Little is known about the tolerance of this plant to salinity stress. Therefore, this study was performed to quantify the morphophysiological and biochemical responses of Satureja rechingeri to salinity stress using nonlinear models.

This experiment was conducted in a completely randomized design with four replications in greenhouse conditions during 2016-2017. Rooted cuttings were prepared from Khorman Pharmaceutical Company located in Khorramabad (Lorestan) and transferred to the research greenhouse for the Department of Horticulture and Landscape Engineering, Campus of Agriculture and Natural Resources, University of Tehran, located in Karaj (Alborz). Rooted cuttings were kept under favorable conditions for about a month and then transplanted into pots. Six weeks after full establishment, the plants were exposed to different concentrations of sodium chloride (0, 2, 4, 8, and 16 dS / m). Parameters including membrane stability, malondialdehyde level, activities of superoxide dismutase and ascorbate peroxidase, proline content, total phenol, plant height, leaf length and width, stem diameter, herbal fresh and dry weight, and percentage and yield of essential oil were measured. Logistic, sigmoid, and peak models were used to quantify these parameters.Findings and

The effect of salinity stress on most of the parameters was significant (except for stem diameter and essential oil percentage). With increasing NaCl salt concentration, in plants under salinity stress, membrane leakage (250%), proline content (430%), catalase (360%), ascorbate peroxidase (550%), superoxide dismutase (320%), total phenol (350%), and malondialdehyde (280%) increased. Salinity decreased plant height (14%), leaf length and width (21% and 23%), fresh weight of shoot (35%), dry weight of shoot (15%), and essential oil yield (15%). Moreover, changes in morphological characteristics under salinity stress were logistic and in biochemical properties (except those in ascorbate peroxidase, which was peak) were sigmoid.

Satureja rechingeri tolerated salinity up to 4 dS / m, but at higher salinities, herbal fresh and dry weight and plant height significantly reduced.

Yellow rust is one of the most important wheat diseases worldwide. This disease can cause high damage to the plant by affecting the yield and yield components. Also, due to the high recombination of the causative agent of this disease, new breeds appear in it every year, which has forced breeders to constantly study this disease and find resistant genotypes.

In order to evaluate the effect of yellow rust disease on some agronomic characteristics of bread wheat genotypes Includes 297 commercial cultivars and landraces of Iran, a field experiment was conducted in alpha-lattice layout with two replications in the Seed and Plant Improvement Institute (SPII) farm, in 1398-1399 crop season. After sowing the seeds and artificially infecting the plants with the disease, some important agronomic traits including yield and related traits as well as infection type and infection percentage were examined.

The results of analysis of variance showed that wheat genotypes have significant differences in terms of all studied traits. An effective correlation coefficient was observed between single plant yield with all traits. The results of stepwise regression analysis showed that the number of grains per spike, 100-kernel weight, grain width, grain length, spike length, grain thickness and spike width have the highest coefficients of determination, respectively. Based on the results of path analysis, the highest direct effect was observed between the number of grains per spike, 100-kernel weight and grain width with grain yield, respectively. The results of factor analysis showed that there were five factors with a justification of about 70% of the total variance, among which the traits had the highest coefficient of explanation in the first three factors. The first factor was called the yield component factor, the second factor was called the spike features factor, and the third factor was called the grain features factor. Based on the results of cluster analysis, genotypes were divided into three groups. In the first group, 53 genotypes with the highest average of single plant yield, number of single plant seeds and spike length; In the second group there were 110 genotypes with the highest mean of plant height, spike density and 100-kernel weight and in the third group there were 129 genotypes with the highest mean values for other traits. A total of 52 wheat genotypes had resistance reaction to pathotype studied in this study.

The study of wheat genotypes under stress conditions of wheat yellow rust (Puccinia striiformis) based on statistical analysis and multivariate analysis showed a significant difference in yield and yield components. Therefore, as in previous studies, the disease studied on wheat was recognized as one of the most important diseases affecting wheat yield. To evaluate and select cultivars and genotypes with higher grain yield, selection should be done using yield-related traits such as number of seeds per spike and number of single plant seeds. Also, based on infection type and percentage, resistance genes can be identified intermediate resistance to the studied pathotype in this study and used in future breeding programs for resistance to wheat yellow rust.

Selection a suitable substrate and also considering the replacement of other inexpensive agro-wastes instead of valuable wood chips is one of the most important points that should be considered in the cultivation and production of medicinal mushrooms. Selecting the appropriate substrate for fungi and enriching the substrate with organic supplements widely affects the production of fruiting bodies and the medicinal value of fungi.

This research was carried out in a cultivation hall equipped with temperature, humidity and light control devices at Zabol University and conducted as a two-way factorial based on a completely randomized design with three replicates. Experimental treatments included 10 types of wood chip base substrates (sawdust): Beech tree, Oak wood chips, Hornbeam wood chips, Poplar wood chips, Eucalyptus wood chips, Tamarisk wood chips, Vine sawdust (pruned stems), Date palm sawdust, Date palm leaf sawdust and Sugarcane bagasse. Also, as the second factor, 10% of nitrogenous organic supplements including wheat bran, rice bran, cotton meal and olive pomace were added to each of the main substrates.

The results of this study showed that the highest yield (145.5 gr), total dry matter (36.8 gr), fruit body protein (27.15 mg/100g D.M), ash (4.97 %), Nitrogen (4.38 mg/100g D.M) and total polysaccharide (14.35 mg/g D.M) were related to the combined substrate of oak wood chips with wheat bran supplementation. The highest amount of fungal water (85.16%) was related to the substrate of eucalyptus wood chips and the highest biological efficiency (19.71%) was related to the combined substrate of oak wood chips with olive pomace. The highest potassium (299 mg / 100 g dry matter), calcium (11.73 mg / 100 g dry matter) and antioxidant capacity (54.25%) were recorded for oak wood chips substrate. The results also showed that in the oak wood chip substrate the shortest time in terms of spawn running time (29.40 days), the shortest time for pinhead formation time (43.13 days) and in the hornbeam wood chip substrate the lowest time registered for precocity (70/26 days).

Although the wood chip substrate, especially oak chip was reported as a suitable substrate for growing Ganoderma applanatum, but easy access and lower cost of other agricultural and industrial lignocellulosic wastes make them a suitable alternative. According to the results of this study, the use of combined substrates and organic supplements in the cultivation and production of medicinal fungi, especially Ganoderma applanatum, is recommended.

Rosa chinensis is an everflowering diploid plant originated from China. The diploid level of the cell in these plant facilities its breeding program. The objectives of the present work were to analyse the phylogenetic relationship, promoter analysis, prediction of protein interaction and structure. Moreover RNA seq analysis of 7 R. chinensis VDAC genes has also been conducted.

VDAC homologues were detected from https://lipm-browsers.toulouse.inra.fr/pub/RchiOBHm-V2/ via BLAST search program. Two pair of primers was design to isolate RcVDAC1 and 2 from R. chinensis cDNA. The PCR amplified segments inserted into PENTER vector and cloned in E-Coli cell and subsequently sequenced. 1500 pb of upstream of seven RcVDAC genes were isolated from lipm-browsers for analyzing by PlantCare software. Phylogenetic tree was laied out by OMEGA 7.0 and all the inputs collected from NCBI and Tair websites. RcVDACs protein interaction predicted via STRING website. RcVDACs proteins structure prediction laied out via Pymole software and R. chinensis transcriptome analysed through RNAseq data by Mev. software.

Isolation and sequencing results of RcVDAC1-2 indicated that their sequence is as exact as Rosa data bank information. The separation of the RcVDACs in different cluster by phylogenetic tree suggests the formation of highly divergent paralogues in RcVDACs. Research results gained by PlantCare showed different light, PGR and stress responsive cis-regulatory element in different RcVDACs promoter region. The presence of high amount of transcription factor binding site related to MYB and MYC TF as well as having regions responsive to phytohormones such as jasmonic acid, abscisic acids, auxin, gibberellic acid and also drought and cold stress likely suggesting the regulatory role of RcVAC genes under abiotic stress. In fact the results gained by RNAseq data confirmed the regulatory role that RcVDAC2 and 5 may play during biotic and abiotic stress condition.

Generally, the analysis of transcriptome by RNAseq, promoter analysis, prediction of 7 of RcVDAC proteins, and their interacting protein and phylogenetic study shed light on the presence of different RcVDAC orthologes and indicates this difference on protein structure; govern their different biological function in different developmental stage and different stress condition. In fact the results gained by RNAseq data confirmed the regulatory role that RcVDAC2 and 5 may play during biotic and abiotic stress condition. In fact the results gained by RNAseq data confirmed the regulatory role that RcVDAC2 and 5 may play during biotic and abiotic stress condition. Key words: Bioinformatics, cDNA, PENTER, BLAST, PlantCare, RNA seq

Increase in ultraviolet radiation (UV (, especially UV B, as one of the consequences of climate change, can disrupt the growth of plants. UV light influences plant growth and metabolism. Various studies have shown that increasing in UV B can have detrimental effects on physiological processes and overall growth of some plants. The use of exogenous plant growth regulators has mostly been effective in reducing the effects of environmental stresses in plants. The present study was conducted to investigate the effect of UV-A and UV-B and foliar application of melatonin and ascorbic acid (ASC) on growth, biomass and morphological and stomatal characteristics of fenugreek in 2019.

The experiment was performed as a split plot in a completely randomized design in the research greenhouses of the Faculty of Agriculture and Natural Resources, Lorestan University. Ultraviolet radiation was considered in four levels as the first factor (including: control, UV-A, UV-B and UV-A+UV-B) and application of osmolytes was used in four levels (Control, melatonin, ASC and melatonin+ ASC) as the second factor. Finally, Plant height, plant width, number of leaves, leaflet length and width, petiole length, crown diameter, plant fresh weight, plant dry weight, leaf fresh weight, number of internodes, number of lateral branches, stomatal gurad cell length and width, stomatal index, stomatal density, chlorophyll and carotenoid contents were measured. The data obtained from the experiment was analyzed using Minitab software. Mean comparison was performed using LSD test method at 0.05.

The results showed that UV-A increased fresh leaf weight, crown diameter, leafstalk length, leaflet length and width, plant height and width, plant fresh weight (12.17%), plant dry weight, number of internodes and content of chlorophyll a (7.4%) and chlorophyll b (3.5%), but reduced the number of lateral branches (15.63%). In contrast, UV-B and UVA+UVB treatments reduced most of the studied traits including plant height (8.09%), leaflet length and width, leafstalk length, chlorophyll a, chlorophyll b, total chlorophyll, plant fresh and dry weight and leaf fresh weight. However, carotenoid content, the number of lateral branches (6.58%) and stomatal index (11.4%) were increased by UV-B and UV-A+UV-B. Application of ASC and melatonin reduced the negative effects of UV-B on fenugreek. In control and UV-A treatments, ASC foliar application had shown the best effects on the studied traits and the highest plant height, number of lateral branches, number of leaves, leaf length and width, chlorophyll, carotenoids, and stomatal index and density were observed in this treatment. While, simultantious application of melatonin and ASC led to the best results under UV-B and UVA+B treatments. Therefore, it can be concluded that the synergistic effect of these two compounds in modulating the effects of ultraviolet stress on fenugreek was remarkable.

In the present study, UV-B radiation and simultaneous radiation of UV-A and UV-B reduced the growth and development of fenugreek. In contrast, UV-A treatment improved yield and morphological characteristics of the plant. In addition, foliar application of melatonin and ascorbic acid modulated morphological destruction and growth indices caused by ultraviolet-B treatment.

Pollination is one of the most critical stages for kernel formation in nut fruits, and without pollination, most fruit will be blanks, so that, to commercial production of hazelnut orchards, should be used two or more cultivars as pollinizer. The aim of this study was to investigate the phenology of flowers, xenia and metaxenia in four commercial hazelnut cultivars and select a suitable and compatible pollinizer for four commercial hazelnut cultivars.

This study was conducted as a two-factor factorial in a completely randomized design. The first factor is pollen, and the second factor is four cultivars having three replications in the period of 2019-2020 in Astara Horticultural Research Station. Gerde Eshkvarat, Riasnet, Daviana and Negret were used as pollinizer cultivars and Ronde, Nemsa, Ganjeh and Atrak cultivars were selected as maternal cultivars. In addition to open pollination (control), self-pollination of maternal cultivars was performed. At the time of fruit ripening, 100 nuts were harvested from each treatment, the variables related to the quantitative characteristics of the fruit, and the nut kernel were determined.

The results of phenology showed that the cultivars were protanderious and the opening time of male flowers (catkins) and shedding of pollen grains were from mid-January to March 24. The opening time of female flower clusters and stigma ready to accept pollen grains varied from January 19 to March 31. The study of xenia and metaxenia in this study showed that the quantitative traits of nut and kernel were strongly influenced by the sources of pollen grains. Increased fruit set and kernel percentage by 87% and 49.84% and the percentage of fruit drop decreased to 31.65% and blank nut by 10.86%. However, when pollen grains of Gerde Eshkorat cultivar were used, the percentage of fruit set, nut and kernel weight and percentage of kernel decreased to 75.86%, 2.48 g and 46.64%, respectively, and the percentage of blank nut with 15.60% and dropping fruit increased by 41.6. In the case of self-pollination, the percentage of fruit drop and the amount of blank nut increased, and the percentage of fruit set, nut, kernel weight, and kernel percentage decreased.

Based on the results, the source of pollen grains affected nut and kernel characteristics of hazelnuts through xenia and metaxenia effects. The effects of treatments on important components of hazelnut yield (nut and kernel weight, kernel and fruit set percentage, fruit drop and blank percentage) were remarkable and it was statistically significant at the 5% probability level. Therefore, for the economic production of hazelnut orchards, pollinizer cultivars should be used that overlap with the main cultivars in terms of pollination period and genetic compatibility.

Salinity stress is one of the factors that reduced the growth and yield of crops. The response of C3 and C4 plants to salinity stress and possible mitigation of the effects of this stress with the application of silicon and nanosilicon may be different according to the photosynthetic pathway of these plants. Therefore, this study was conducted to compare the response of wheat as a C3 plant and sorghum as a C4 plant to the effect of silicon and nanosilicon application on salinity stress mitigation.

Two experiments were conducted in a completely randomized design with factorial arrangement in pots filled with soil at Sari University of Agriculture and Natural Resources in 1398. The salinity factor was at two levels included 0 and 100 mM NaCl and the silicon factor was at three levels included 0 and 2 mM potassium silicate and 2 mM nanosilicon (SiO2)). Both forms of silicon were applied as foliar application. Plant photosynthesis-related traits were measured after 13 days of treatments the next day the plants were harvested for growth measurement and other biochemical assays.

The results of this study showed that salinity caused a significant reduction in fresh and dry weight of plants in both wheat and sorghum plants. Application of silicon in wheat and application of nanosilicon in sorghum caused a significant increase in fresh and dry weight of plants under salinity. Application of silicon and nanosilicon had no significant effect on stomatal conductance and transpiration of wheat and sorghum plants under salinity. In wheat plants, silicon foliar application significantly increased photosynthesis rate under salinity, but nanosilicon had no significant effect. On the contrary in sorghum, the use of silicon had no significant effect on the photosynthesis rate under salinity, but nanosilicon increased the photosynthesis rate of sorghum plants. In sorghum plant, under salinity conditions, the use of silicon and nanosilicon reduced the amount of hydrogen peroxide contents by 21 and 30%, respectively, and the amount of lipid peroxidation by about 13 and 23%, respectively. However, the use of silicon and nanosilicon did not indicated a significant effect on the content of hydrogen peroxide the amount of lipid peroxidation wheat plants grown under saline condition. The application of silicon in wheat plants increased 58% of the total fresh weight and 68% of the total dry weight of plants under salinity, although the application of nanosilicon had no significant effect. The use of silicon and nanosilicon increased the fresh and dry weight of sorghum plants under salinity, but the additive effect was greater by application nanosilicon, so that the total dry weight of sorghum plants under salinity in nanosilicon treatment were 75% higher than plants without this treatment.

This study showed that the use of silicon in wheat plants under salinity improved photosynthesis and thus reduced the effects of salinity on growth to some extent, but nanosilicon in this plant did not have such an effect. Conversely, in sorghum plants under salinity, the use of nanosilicon by reducing the amount of hydrogen peroxide and lipid peroxidation, reduced the oxidative stress caused by salinity and increased the photosynthesis rate of the plant, which led to more growth of plants under salinity stress. Such cases were not observed with the use of silicon.

Among oilseeds, sesame (Sesamum indicum L.) is known as the queen of oilseeds due to its significant amount of antioxidant compounds, essential amino acids and unsaturated fatty acids. Among the necessary managements to achieve maximum crop production, the selection of cultivar, density and planting pattern could be mentioned. Different sesame cultivars have various growth characteristics (for example, branching) and each of them is suitable for a planting method with a certain density. The aim of this study was to evaluate the planting pattern and suitable density for two sesame cultivars.

In this study, the effect of planting pattern (single or double row(s) on ridges), plant density (20, 30 and 40 plants m-2) and sesame cultivars (Oltan and Naz Tak Shakheh) based on factorial experiment in a randomized complete blocks design were evaluated in three replications during 2019 and 2020 in Karaj region. Plant height, grain yield and yield components, dry matter yield, harvest index and oil percentage and yield were evaluated. Statistical analyzes were performed using SAS software and LSD test was used to compare the main means and slicing was used to compare the means of interactions.

Analysis of variance showed that effect of planting pattern factor on plant height and dry matter yield, plant density factor on all traits (except 1000-seed weight) and cultivar factor on all traits (except harvest index) were significant. Comparison of means showed that the mean of plant height in planting pattern of double rows on ridges (126 cm) was significantly higher. Among the yield components, the number of capsules per plant at densities of 30 and 40 plants m-2 (57 and 60, respectively) were the highest, which were statistically significant compared to the density of 20 plants m-2 (50). The number of seeds per capsule at the density of 20 plants m-2 was the highest (58) which showed a statistically significant difference compared to the other two densities. Among the studied densities, the highest grain yield (993 kg ha-1) was obtained from the density of 40 plants m-2 and the lowest grain yield (798 kg ha-2) was obtained from the density of 20 plants m-2. Among the two studied cultivars, Oltan cultivar had the highest yield and grain yield components which showed a statistically significant difference compared to Naz Tak Shakheh. The highest oil yield was produced by Oltan cultivar in each of the densities of 30 and 40 plants m-2, which statistically did not show a significant difference in planting pattern of single or double row(s) on ridges.

This study showed that Oltan cultivar is recommended in planting pattern of single row on ridges and in density of 30 plants m-2 for Karaj region.

Drought stress is one of the most common environmental stresses in agriculture crops production process worldwide. Asparagus officinalis is the most economically important species of asparagus which is susceptible to some of the most common biotic and abiotic stresses. According to reports, Iranian species of asparagus can well tolerate some of unsuitable soil conditions. The purposes of current study were identification and morphological evaluation of different accessions of A. azerbaijanensis Iranian species, evaluation of seed germination indices and seedling growth of Iranian asparagus under drought stress condition, comparing of Iranian accessions tolerance rate with Mary Washington commercial cultivar and introducing of superior accessions for using in asparagus breeding programs with aim of producing drought resistant hybrids.

The current study was carried out in two different sections at university of Zanjan, during 2020-2021, which the first experiment was related to collection and morphological evaluation of two wild accessions of A. azerbaijanensis species and the second experiment was related to evaluation of drought stress (in four levels: 0 (control), 5, 10 and 15 % of polyethylene glycol) on seed germination indices (germination speed and percentage) and seedling growth (length of radicle and plumule, radicle length to plumule length ratio and fresh and dry weights of radicle and plumule) of Iranian asparagus in laboratory condition.

The average of spear length and diameter in Ahar and Makou accessions were 48.94 cm and 4.70 mm. The mean numbers of seed per fruit and fruit per plant were 2.37 and 159.40 numbers in evaluated accessions and average of 10.28 cladode number was evaluated in accessions of A. azerbaijanensis species. The highest seed germination speed and percentage and also length of radicle and plumule were recorded in Gazanak accession under stress conditions. The percentage and speed of seed germination in Gazanak accession were averagely 56.73 and 70.52% higher than those of Mary Washington commercial cultivar under drought stress conditions. The mean comparing results for fresh and dry weights of radicle and plumule traits showed that fresh and dry weights of radicle and plumule decreased by increasing of stress level in all of evaluated accessions.

Wild accessions of A. azerbaijanensis species, due to their suitable morphological variation and producing of spears with desired taste and size, are suitable candidates to employ in asparagus breeding programs with the aim of producing asparagus with superior vegetative growth. Also, the superiority of Iranian asparagus different accessions over the commercial cultivar used in this study in tolerating of water deficit conditions and stress, promises the possibility of further evaluation of Iranian asparagus in asparagus breeding projects and studies with aim of producing dry resistant cultivars. Keywords: Drought stress, Germination percentage, Iranian asparagus, Polyethylene glycol.

One of the main factors affecting the growth of greenhouse tomato transplant is the choose of desired cell size or volume of the tray. So that, larger cells provide more space for better transplant growth, but as the cell volume or size increases, the space required to produce the transplants increase. Therefore, it is important to determine the appropriate cell size that produces vigorous transplants. On the other hand, improved seedling growth in various vegetables such as tomatoes due to the use of humic acid has been reported by various researchers. This study was performed to investigate the effect of tray cell volume and foliar application of humic acid on morphological and physiological characteristics of tomato transplants.

A factorial experiment in a completely randomized design with three replications and two factors include tray cell volume (15, 20 and 22 cm3) and humic acid foliar application (0, 1.5, 3.5 and 5.5 g/l) was conducted in a greenhouse at the University of Hormozgan. The growing substrates were 70% coco peat and 30% perlite. Since the fourth week onwards, with the appearance of two pairs of true leaves, the seedlings were sprayed by humic acid fertilizer with concentrations 0, 1.5, 3.5, 5.5 g/l every other day for 15 days. 7 weeks after planting, seedling characteristics such as morphological and physiological traits and concentrations of leaf N, P and K were measured. At the end of the experiment, data analysis was performed using SAS software (version: 9.1). The means were compared with Duncan test at a statistical level of 5%.

The results of this study showed that reducing of try cell volume decreased evaluated traits significantly so that the lowest mean of these traits was obtained in cell volume of 15 cm3. Reduction of cell volume from 22 to 15 cm3 significantly reduced the morphological traits including plant height, stem length, root fresh weight, fresh and dry weight of shoots, and leaf area by 12.7, 16.2, 21.9, 15.1, 18.8 and 18.4%, and physiological traits including Fv/Fm and PI by 10.7 and 25.7, respectively. Application of humic acid improved morphological and physiological characteristics of transplants and in most cases, the highest mean of under study traits were obtained by 5.5 g/l humic acid. With decreasing the tray cell volume from 22 to 15 cm3, the leaf nitrogen, phosphorus, and potassium concentration decreased by 15.7%, 18.9%, and 16.4%, respectively. However, foliar application of humic acid caused a significant increase in the leaf elements content, compared to the control. In general, the highest content of nitrogen (1033.91), phosphorus (224), and potassium (37534.94 mg/kg DW) were obtained with the application of humic acid in concentrations 3.5, 1.5, and 5.5 g/l. On the other hand, foliar application of humic acid improved the under study traits when compared to the control. Overall, these results indicate that humic acid could compensate for root growth restriction in trays with small cells.

The results of this study showed that reducing the cell volume of the tray leads to a significant reduction in physiological and morphological characteristics of tomato transplants. While the use of humic acid could improve nutrient uptake and vegetative growth of seedlings and offset the negative effects of low volume tray cell by the use of humic acid. Foliar application of humic acid improved morphological and physiological traits and absorption of nitrogen, phosphorus, and potassium. Therefore, it seems that the use of humic acid can be suggested as a strategy to produce higher quality transplants.