b

Durum wheat (Triticum turgidum L. subsp. Durum) is the only tetraploid wheat species with high nutritional values. Regarding the high adaptability of this cereal crop to the Mediterranean conditions, achieving high-performance and stable varieties has a critical role in expanding the cultivation areas followed by increasing its production. Evaluation of genetic diversity is the main foundation of any breeding program, that can provide useful information about population structure as well as growth and agronomic characteristics of the studied genetic materials. The main objective of the present study was to investigate the genetic diversity in a set of durum wheat genotypes in terms of some agronomic and morphological traits.

In this study, the diversity of morphological and agronomic traits of 172 durum wheat genotypes along with four check cultivars including Saji, Zahab, Sepand and Tabesh were investigated under rainfed conditions during two cropping seasons (2022-2023 and 2023-2024). The experiment was conducted in an augmented design with seven incomplete blocks. To investigate the genetic diversity, some genetic statistics including environmental, phenotypic and genotypic coefficient of variation, broad sense heritability, genetic gain and mean-based genetic gain were calculated. Furthermore, multi-trait genotype-idiotype distance index (MGIDI) was used to identify the superior genotypes for all measured traits. A two-way genotype-trait dendrogram based on cluster analysis was also used to group the studied genotypes and traits.

The results of this experiment showed that there were significant differences among the studied genotypes for number of days to heading, grain filling period, plant height, 1000-kernel weight and grain yield. Grain yield and yield components had the highest phenotypic and genotypic coefficient of variation (PCV and GCV, respectively). Broad-sense heritability was also estimated to be moderate to high for most of the measured traits in both years. The highest genetic gain was observed for grain yield and plant height in the first year and 1000-kernel weight, number of spikes, and spike density in the second year. The results of MGIDI index identified 26 genotypes (No. 5, 8, 13, 14, 16, 20, 21, 26, 51, 81, 86, 87, 91, 92, 95, 96, 97, 99, 100, 102, 103, 155, 158, 163, 166, and 174) as superior genotypes. These genotypes had significant superiority over other genotypes in this experiment in terms of all measured traits. The results of cluster analysis also distiguished the superior genotypes identified by the MGIDI index from other genotypes and grouped them in a separate cluster.

According to the results of multi-trait genotype-idiotype distance index and grouping of cluster analysis, genotypes 102, 100, 92, 87, 21, 174, 86, 8, 14, and 5 can be recommended as the superior and ideal genotypes of this experiment for use in future breeding programs in durum wheat.

Durum wheat is considered one of the most important crop plants globally and in Iran, and it’s growth and yield is consistently affected by drought stress in Mediterranean regions, especially with global climate changes. However, local varieties or landraces of this crop can serve as valuable genetic resources for identifying and introducing drought-tolerant genotypes. The objective of the present study was to evaluate the drought tolerance of Iranian and foreign durum wheat landraces (primarily from the Fertile Crescent) in order to identify and introduce superior genotypes.

In this study, 150 durum wheat landraces from the Fertile Crescent were assessed for drought tolerance using stress tolerance indices. The experiment was conducted in an augmented randomized complete block design with four check varieties under supplementary irrigation and rainfed conditions in the research field of Razi University, Kermanshah, Iran, during two consecutive years (2019-2020 and 2020-2021). Stress tolerance indices were calculated after measuring grain yield under both supplementary irrigation and rainfed conditions. Cluster analysis, principal component analysis, and biplot analysis were used to screen the studied landraces for drought tolerance. R software version 4.3.1 was used to calculate stress tolerance indices and homogeneity test of variance of experimental errors. R software was used to perform principal component analysis and determine the optimal number of groups based on Silhouette method in Factoextra package.

The results of combined analysis of variance of the two years data revealed a significant difference among the studied durum wheat landraces for grain yield under both supplementary irrigation and rainfed conditions. The interaction of genotype × year was also significant, indicating different responses of the genotypes during two experimental years. Biplot analysis of genotype × index for the first year data showed that all the studied stress tolerance indices appeared in the first, third, and fourth zones of the coordinate axes, but more important stress indices including MP, TOL, GMP, HM and STI were located in the fourth zone, which were used to identify superior with high yielding drought-tolerant genotypes. A similar trend with minor differences was observed in the second year. In total, the studied durum wheat landraces were categorized into four distinct groups from drought-sensitive to drought-tolerant based on the genotype × index biplot.

Based on the results of this study, TOL, GMP, HM, STI and MP indices were selected as suitable and useful indices for distinguishing and identifying high-yielding drought-tolerant durum wheat landraces. Accordingly, the studied durum wheat landraces in terms of drought tolerance or sensitivity were grouped into four distinct groups from sensitive to tolerant. Among the studied landraces, two landraces, 44SAU and 9IRQ from Sudan and Iraq, respectively, were identified as superior landraces.

Salinity is one of the most important limiting factors for the production of all agricultural products in many regions of the world. In saline environments, the absorption of nutrients in plants is reduced. Adaptation of plants to environmental stresses requires morphological, physiological, and biochemical changes, including the accumulation of osmolytes, which can play an adaptive role during osmotic stress. One of the common responses of plants to osmotic stress is the accumulation of proline, which is an important and well-known osmolyte that accumulates in many plant organs during stress. The objective of the present study was to evaluate the expression pattern of P5CS and P5CR genes and to investigate some physiological traits in two bread wheat varieties at the early growth stages under salinity stress conditions.

The experiment was conducted as a split plot factorial in completely randomized design with four replications. The seeds of the studied wheat cultivars were disinfected using 10% ethanol and washed with distilled water, and then sown in 32 pots filled with cocopeat and perlite in a ratio of 2:1. Fifteen seeds of each variety were sown in each pot. Salinity stress was applied after germination and establishment of the seedlings with irrigation water, so that during the irrigation of plants, the control pots were irrigated with strile distilled water (0 dS/m) and the salinity treatment pots were irrigated with saline water containing NaCl (12 dS/m). After the plants reached the tillering and stemming growth stages, five plants were randomly sampled from each experimental pot, and biochemical traits including chlorophyll, proline, cellular oxidation index, potassium and sodium levels were measured at both growth stages. The expression of some genes including P5CS and P5CR was also evaluated on leaf samples.

The results of this experiment showed that the effects of salinity stress and variety on all measured biochemical traits (except for the effect of variety on sodium content) were significant. Evaluation of chlorophyll a and b content showed a decrease in the content of both chlorophyll a and b in both varieties, and this decrease was more noticeable at the tillering growth stage. The levels of catalase and superoxide dismutase enzymes increased in both Ehsan and Baharan varieties under the influence of salinity stress, and this increase was more considerable in Ehsan variety at the stemming stage. Sodium content also increased under salinity stress, but this increase was not significant in Baharan variety at the tillering stage and in Ehsan variety at the stemming stage. In contrast, the changes in potassium content due to salt stress were different in two varieties, so that the potassium level in Baharan showed a significant increase at both growth stages due to salinity stress, while in Ehsan it decreased significantly at tillering stage, but its change wasn’t significant at stemming stage. Proline levels also showed a significant increase under salinity stress conditions at both growth stages and in both varieties. In addition, the activity of both genes P5CS and P5CR also increased in both wheat varieties under salinity stress, indicating that there is a direct relationship between the changes of proline levels and the activity of genes involved in its biosynthesis pathway (i.e. P5CS and P5CR) under salinity stress conditions.

Evaluation of biochemical traits and gene expression in the studied two wheat varieties in the current research showed that Ehsan variety can be introduced as a salinity-tolerant cultivar and used in future breeding programs to increase salinity tolerance in wheat.

In order to investigate the response of sage to delayed planting, the present study was performed as a randomized complete block design with three replications in the Meshkin Shahr Faculty of Agriculture research farm in 2020.

The treatments were two planting dates including conventional planting date (as control) and delayed planting which were cultivated on May 5th and June 15th, respectively.

The results showed that delayed planting-mediated high temperature significantly increased total phenol, total flavonoids, anthocyanin, essential oil yield, and antioxidant properties by 25, 44, 85, 80, and 39 percent, respectively and decreased plant height, leaf width, and shoot fresh and dry weight by 8, 13, 41 and 34 percent, respectively compared to control. There were also negative and significant correlations between plant fresh or dry weight and essential oil percentage as well as the other measured phytochemical constituents. In addition, some essential oil constituents including α-Thujone, β-Thujone, β-Pinene, Borneol, and Viridiflorol were increased by 23, 15, 28, 37, and 46, respectively under heat stress compared to the control.

In general, an increase in secondary metabolite in delayed planting treatment indicates that sage plants probably employed the strategy of allocating more photosynthetically fixed carbon to the biosynthesis of secondary metabolites to improve plant tolerance to high-temperature conditions via a decrease in reactive oxygen species production and/or increase in the scavenging potential of those radicles.

Urea is one of the most widely used fertilizers in agricultural practices; however, its high solubility in water leads to rapid leaching from the soil before plants can effectively absorb it. This issue results in significant fertilizer losses, increased agricultural costs, and various environmental concerns. A promising approach to address this challenge is the application of organic materials to coat urea granules, thereby slowing their dissolution rate in water. In this study, to mitigate fertilizer loss and enhance efficiency, carnauba wax (CW) was selected due to its biocompatibility and abundance. Additionally, urea granules were coated separately with CW combined with paraffin wax and stearic acid, polyethylene wax, and paraffin wax to evaluate the effectiveness of these materials in reducing urea dissolution.

The method of dip-coating was employed as the primary technique for applying the coating onto the urea granules. To assess the release of urea over time, a specific quantity of the coated urea granules was carefully placed into 10 ml of distilled water, and the solution was monitored by collecting samples at predetermined time intervals. The concentration of urea released into the water at each interval was quantitatively determined using a UV-VIS spectrophotometer. Additionally, the diameters of the various coatings formed on the urea granules were examined and recorded on the seventh day of the experiment using a stereo microscope equipped with 40X magnification for precise measurements.

The release of urea was monitored over a 41-day period, and the results revealed significant differences in the release rates based on the coating material used. Urea granules coated with carnauba wax exhibited the slowest release rate, with only 71.5% of the urea released by the end of the 41-day observation period. In contrast, granules coated with a mixture of carnauba wax and paraffin wax released their entire urea content into the water within just 7 days. Among the coatings tested, carnauba wax demonstrated the highest efficiency with a coating diameter of 0.504 mm, which also represented the smallest thickness compared to the other coating formulations.

The study results revealed that carnauba wax serves as an efficient coating material for urea granules, significantly prolonging their release time. This wax offers numerous benefits due to its natural origin, biocompatibility, biodegradability, and non-toxic properties. Its application enhances sustainability while ensuring safety, making it a highly suitable choice for controlled-release purposes in agricultural or similar settings. These findings highlight its potential to revolutionize fertilizer usage, reducing environmental impact and improving cost efficiency.

The present research was conducted with the aim of investigating the effects of seaweed (Sargassum vulgare and Spirulina platensis) on the growth, physiological, and biochemical characteristics of violet plant (Viola×wittrockiana).

The effect of drought stress at three levels (100% field capacity - no stress; 75% F.C.- mild stress; and 50% F.C.- severe stress) and algal extract with four levels (control, 1% liquid Spirulina extract, 2% liquid Spirulina extract, 1% liquid Sargassum extract, and 2% liquid Sargassum extract) was investigated in a factorial experiment based on a randomized complete block design in three Replication.

The 50% F.C. significantly reduced morphological traits, flower number, shoot and root dry weight, and flower longevity, as well as the number of photosynthetic pigments in the plant. The application of 2% Sargassum extract under 75% F.C. (mild drought stress) conditions resulted in the highest levels of total phenols, flavonoids, and antioxidant activity, which are correlated traits. Drought stress increased the activity of catalase, peroxidase, superoxide dismutase, and malondialdehyde, as well as soluble carbohydrates and proline, all of which were positively influenced by the algal extract (especially at a concentration of 2% liquid Sargassum extract). Among the algae, Sargassum had a greater positive effect on all studied traits, and the 2% liquid Sargassum extract was more effective.

The Pansies (Viola) was relatively sensitive to drought stress, and the algal extract mitigated the negative effects of drought stress by enhancing the growth and production of metabolic compounds in Pansies.

Periwinkle herb, with the scientific name (Catharanthus roseus (L.) G.DON), is one of the most important medicinal plants globally. Besides having aesthetic features and ornamental applications, the plants’ leaves and root are rich in very important alkaloids. It is used in the chemotherapy of various cancers and the treatment of hypotension.

In order to investigate the effect of growth regulator and spraying by zinc and magnesium nanoparticles under the conditions of drought stresses on total alkaloids, anthocyanin, total chlorophyll, the weight of wet and dry branches contain alkaloids, and the number of lateral branches of the periwinkle herb, an experiment was arranged with a factorial layout based on a completely randomized design under greenhouse conditions during years 2020 and 2021 in Tehran, Iran. The first factor was the dryness factor using evaporation pans (at three levels of 40, 60 and 80 mm), the second factor comprised the growth regulators (Shahid, auxin, gibberellin, cytokinin each at a concentration of 50 ppm) and the third factor included the nanoparticles (control, Zn, and Magnesium, each at a concentration of 1 mg, and the combination of zinc and magnesium, each at a concentration of 0.5 mg) were applied.

The results showed that in study of the effects of drought stress and spraying of zinc and magnesium nanoparticles on all investigated traits (total alkaloid, anthocyanin, total chlorophyll, fresh and dry weight of alkaloid-containing branches, and the number of lateral branches), there was a statistically significant difference at the level of 1% (P≤0.01). Also, in the investigation of the effects of growth regulators on investigated traits other than total alkaloid, a statistically significant difference was established at the level of 1% (P≤0.01). In the investigation of the mutual effects of drought stress and growth regulators on the fresh weight of alkaloids-containing branches, a statistically significant difference was established at the level of 1% (P≤0.01). The highest dry weight of aerial parts was observed under optimal irrigation conditions and under the influence of the gibberellin hormone (34.96 gr). However, in other cases, no statistically significant effect was observed on the target traits.

Drought stress revealed defense mechanisms such as anthocyanin pigments and secondary compounds, and total alkaloids also increased with increasing drought stress. The highest percentage of total alkaloids was obtained under severe drought stress (1.57%). The use of micronutrient fertilizers in nano form increased the accumulation of dry matter and secondary compounds, and the effect of magnesium was greater than the effect of zinc. In the application of hormones, the use of gibberellin hormone had a greater effect on the fresh and dry weight of shoots under optimal irrigation conditions and drought stress.

Saffron (Crocus sativus L.) is a perennial, sterile, and triploid plant. Moreover, dried saffron stigmas have many uses in the food and medicine industry. Saffron plants propagate by corms due to sterility. Therefore, it has limited diversity and a poor plant breeding background, leading to genetic erosion. As a result, being under severe risk of genetic erosion is an obstacle to the breeding and production of saffron. The objective of this study was to investigate the diversity among saffron ecotypes, to evaluate the correlation between morphological traits and the amounts of secondary metabolites, and to classify the ecotypes.

A complete randomized block design with two replications in three harvests has been conducted to investigate the biological diversity of 22 saffron accessions collected from different regions of Iran at the Tehran University research farm, Mohamadshahr, Alborz, Iran. The most important morphological traits and amount of secondary metabolites, including crocin, picrocrocin, and safranal, were measured by using high-performance liquid chromatography.

Analysis of variance showed significant differences among accessions for studied traits in three consecutive harvests. Qaenat accession had the highest means of obtaining the most morphological characteristics. The factor analysis based on PCA showed that the two first components explained 97 percent of the total variance of traits. The traits of leaf length, stigma fresh weight, stigma length, and safranal in the first component and picrocrocin, crocin, and petal length in the second component had the most positive role in justifying 66.7 percent of the total variance, respectively. Based on cluster analysis, accessions were divided into five clusters. The Qaenat and Firdos 16 accessions had the most genetic similarity, and the Qaenat and Arak accessions had the farthest genetic distance. Moreover, the studied traits are divided into three clusters, so that the amount of crocin and picrocrocin and petal length are in the first category, the amount of safranal, the length of leaf, length of stigma and length of flower, fresh weight of flower and stigma are in the second category, and the final yield, the total number of flowers, and dry weight of stigma are in the third category.

Although studied accessions were cultivated and preserved in the same geographical environment, they had significant differences at morphological and phytochemical levels. Therefore, it can be concluded that the origin of the observed diversity is the result of the existence of diversity at the genome, transcriptome, or epigenome levels.