معرفت قاسمی کلخوران

This research was conducted in order to evaluate the reaction of different barley genotypes and to understand better the genotype × environment interaction effect in different areas of the country's cold climate, and to select stable genotypes.

Four barley genotypes, including Jalgah, Mehtab, Bahman, CB-96-10, along with four imported genotypes in five stations of Karaj, Zanjan, Jalgarokh, Ardabil, and Miandoab in the form of complete randomized block design with three replications in two consecutive years of evaluation became.

In Eberhart and Russell method, G1, G4, and G6 genotypes; in parametric methods G1, G4, G6, and to some extent G7 genotypes and; in nonparametric methods G1, G4, and G6 genotypes were identified as stable genotypes. According to the comparison of average performance, sustainability criteria and agricultural characteristics and general compatibility using AMMI analysis, G6, G1, and G7 genotypes were recognized as the most suitable and most compatible genotypes, respectively and can be considered as climate compatible cultivars in all cold regions of the country. Genotypes G2, and G3 are also considered varieties with private compatibility.

According to the results, G6, and G1 genotypes can be considered as the most compatible genotypes in all cold regions of the country, and G2, and G3 genotypes can also be considered as genotypes with high private compatibility in high potential regions.

Drought stress is one of the most common limiting factors for crop production. Due to its detrimental effects on numerous physiological and biochemical processes, this stress restricts the growth and development of plants. In this regard, the application of stress modulators (methanol, silicon and humic acid) has been found to enhance plant growth and grain yield while also increasing its resistance to abiotic stresses. On the other hand, stress modulators can lessen the effects of stress toxic by reducing malondialdehyde and hydrogen ‎peroxide accumulation and keeping the effectiveness of the photosynthetic apparatus‎. Therefore, measurement of traits of such as antioxidant enzymes activity, chlorophyll content, proline and soluble sugars content, malondialdehyde content, electrical conductivity are as indicators of plant response to environmental stress. Although, several strategies have been developed to decrease the effects caused by drought stress on plant growth. But, among them, the application of stress modulators (methanol, nano silicon, and humic acid) plays a very important role in yield improvement. The aim of this study was to evaluate the effects of foliar application of stress modulators (methanol, nano silicon and humic acid) on the activity of antioxidant enzymes, compatible osmolytes, photosynthetic pigments content and grain yield of wheat in different irrigation regimes.

an experiment as factorial was conducted based on randomized complete block design with three replications in Agricultural and Natural Resources Research Station of Ardabil, Ardabil, Iran, in 2022-2023 growth season. The treatments were different irrigation regimes (normal irrigation as control; irrigation withholding at 50% of booting and heading stages) and foliar spraying of stress modulators (foliar spraying with water, foliar spraying of methanol (25% volume), nano silicon (50 mg.L-1), humic acid (300 mg.L-1), foliar spraying of methanol and silicon, methanol and humic acid, nano silicon and humic, methanol with nano silicon and humic acid). In each plot, there were six rows with two m long. In this experiment, the wheat cultivar ‘Hiran’ was employed. For this cultivar, 400 seeds.m-2 is the optimum density. The used nano silicon had an average particle size of less than 30 nm and the special surface of particles was more than 30 m2.g-1. They were product of Nanomaterial US Research which was provided by Pishgaman Nanomaterials Company of Iran. For a better solution, deionized water was mixed with nano Si powder and placed on a shaker with ultrasonic equipment (100 W and 40 kHz). Two phases of period growth, BBCH 21 and 30 were used for the foliar application of nano silicon.  In this study, the activity of antioxidant enzymes (Catalase, peroxidase, and Polyphenol oxidase), compatible osmolytes (Proline and soluble sugars), photosynthetic pigments content (Chlorophyll a, Chlorophyll b, total chlorophyll, and carotenoid), H2O2, MDA, protein content and grain yield of wheat were investigated.

The result indicated that both application stress modulators (methanol, silicon and humic acid) at irrigation withholding in booting stage decreased malondialdehyde content (39.79%) and electrical conductivity (31.25%), but increased activity of peroxidase (4.89%), polyphenol oxidase (7.73%) enzymes, soluble sugars (22.15%), chlorophyll a (33.48%), chlorophyll b (24.96%), leaf protein content (25.09%) and grain yield (36.21%) in compared to the no application of stress modulators under irrigation withholding in booting stage.

According to our findings, applying stress modulators (methanol, silicon and humic acid) under water limitation often reduced this damage by strengthening the defensive mechanisms, particularly antioxidant enzymes and compatible osmolytes (Proline and soluble sugars). In summary, our results indicated that application of stress modulators upgrade plant physiology and trigger the cellular defense of wheat plants against severe water limitation. Therefore, in can be suggested that applying stress modulators as individual and integrated could enhance grain yield of wheat under water limitation conditions due to improving of physiological and biochemical characteristics.

Drought is considered one of the most important factors limiting crop performance worldwide. Consumption of humic acid on plants, in addition to soil fertility, increases plant tolerance to drought and soil water holding capacity. Chitosan is also a natural biopolymer modified from chitin and non-toxic, biodegradable, and environmentally friendly substances that acts as a potential stimulant in agriculture. Chitosan and humic acid reduce the negative effects of abiotic stresses. Accordingly, due to the drought crisis in arid and semi-arid regions, in this study, the modulating effect of humic acid and chitosan foliar application on wheat tolerance to drought stress at the end of the season was investigated.

This experiment was performed to study the effect of foliar application of chitosan and humic acid on improving drought tolerance of wheat genotypes in the form of split split plots based on a randomized complete block design with three replications. The main plot includes irrigation treatments at two levels (full irrigation and cessation of irrigation in spike stage), sub-plots including three wheat genotypes including Mihan, CD-93-9, and CD-93-10, and sub-plots including humic acid and chitosan foliar application levels (Zero, 2 g.L-1 of humic acid, 3 ml.L-1 of chitosan and the combination of humic acid and chitosan). The experiment was carried out on a field in Ardabil Agricultural Research Station. Sowing was done in October 2020 with a planting density of 450 seeds per square meter. Chemical fertilizer based on NPK soil test at 50, 100, and 20 kg.ha-1, respectively was added to the soil before planting. Each genotype was planted in 1.5 cm by 7 m plots. The length of each row was 7 m and the distance between the rows was 20 cm and the seeds were sown at a depth of 5 cm. STAR 2.01 statistical software was used to analyze the data including data analysis of variance and comparison of means by LSD method at a 5% probability level.

The results showed that the interaction effect of cultivar × stress × foliar application was significant in all studied traits including plant height, number of seeds per spike, number of spikes, spike length, and grain yield, except the number of tillers per plant and 1000-seed weight. Regarding the number of tillers per plant, the interaction of cultivar × foliar application was significant and for 1000-seed weight, the interaction of cultivar × stress and stress × foliar application was significant. Although there were differences in the response of wheat genotypes to the foliar application under both stress and non-stress conditions, in most traits such as number of tillers, number of seeds per spike, spike length, plant height, and 1000-seed weight, the best result was the simultaneous use of chitosan and humic acid. Was obtained. Also, both under non-stress and under stress conditions, the highest grain yield of the studied genotypes was obtained in simultaneous foliar application of chitosan and humic acid. In general, it can be concluded that the combination of chitosan and humic acid (2 g.L-1 humic acid and 3 ml.L-1 chitosan) significantly showed the best results in increasing the yield and yield components of wheat compared to the control treatment in both non-stress and the end of the season drought stress conditions.

Foliar application of humic acid and chitosan increased and improved the studied traits, both under drought stress and non-stress conditions in wheat genotypes compared to non-foliar application. The maximum number of tillers, number of seeds per spike, number of spikes, spike length, 1000-seed weight, and grain yield were obtained by foliar application of chitosan and humic acid under both full irrigation and stress conditions. Therefore, it is recommended to use simultaneous spraying of chitosan and humic acid to increase tolerance and achieve higher performance. Also, the study of different concentrations of these two substances in combination with each other and at different stages of wheat growth can determine the best dose and time of their consumption in this strategic crop, which is recommended to conduct studies in this regard.

Studying the nature of the genotype×environment interaction provides the possibility of identifying stable and compatible genotypes for breeders, and it has always been one of the important issues in the production and release of new stable and high-yield cultivars in breeding projects. The current research was conducted with the aim of identifying the response of genotypes in each of the studied areas, based on AMMI and GGE biplot models and better understanding of the genotype×environment interaction and determining the level of public and private stability of cultivars. Twenty facultative and winter wheat genotypes were cultivated and evaluated in nine regions (18 environments) during the two crop years of 2017 to 2019 in a randomized complete block design with three replications. In order to analyze the compatibility and stability of genotypes, AMMI and GGE biplot models were used. The results of AMMI analysis showed that the main effect of genotype, genotype×environment interaction effect and the first six principal components were significant at the 1% probability level. The first and second principal components explained about 51% of the sum of squares of the genotype×environment interaction effect. Based on SSiASV and SSiWAAS simultaneous selection indices, genotypes G13, G1, G3, G2, G6, G16, and G7 were identified as the best genotypes. Biplot analysis showed that the genotypes G1, G3, and G6 with average yield had the highest general stability compared to other genotypes. None of the genotypes can be considered as desirable genotypes that have high average yield and high yield stability, but genotype G16 and in the next stage the genotypes G1 and G13 were close to the ideal genotype. Polygon biplot model divided environments into two environmental groups (macro environment) and genotypes into four groups. The first environmental group included Kar1, Kar2, Qaz1, Qaz2, Ham1, Ham2, Mia2, Egl1, Jol2, Ard2, and Ara1 environments, with G16, G17, and G4 genotypes having the highest yield. The second environmental group included Mas1, Mas2, Mia1, Ard1, Jol1, Ara1, and Egl2 environments, and in this macro environment G2, G11, G7, and G12 genotypes had the highest yield. Finally, the examination of the relationships among the environments showed a very high correlation among the investigated environments, which indicated the similar behavior of the genotypes in the most of the tested environments.

The melon aphid, Aphis gossypii Glover is a polyphagous pest that causes serious damage to various crops including vegetables. This insect is one of the most important pests of cucumber plant in greenhouses throughout the world. Biological control is one of the alternative or complementary methods for chemical control that can be used in IPM programs. The use of natural enemies can be very effective in reducing the population of invasive pests. Among biological control agents, Chrysoperla carnea (Stepehns) has attracted the most attention as an effective pest control agent. Also, using resistant cultivars is one of the important methods for pest control management. Therefore, the use of resistant cultivars with effective biological control agents plays an important role in pest control. The aim of this study was to investigate the effect of some cucumber cultivars on biological and population growth parameters of A. gossypii and the functional response of C. carnea.

Four cucumber cultivars including Arshia, Caspian, Danito and Tarom were used in this study. Life table experiments were performed using 50 first instar nymphs (< 24 h old) for each cucumber cultivar. The nymphs were separately reared on the leaves of each cultivar. After emergence of adults, their fecundity and survival were recorded daily until all of them were dead. The parameters were estimated using TWOSEX-MS Chart, life table procedure. In the functional response experiment, different densities (2, 4, 8, 16, 32, 64 and 128) of 3- and 4-d- old aphid nymphs were separately offered to the third instar larvae of C. carnea, which were starved for 16 h before the test. The number of consumed preys was recorded after 24 h. The experiment was repeated 10 times for each aphid density and cucumber cultivar. Logistic regression analysis and nonlinear least square regression procedure were used to determine the type of functional response and estimate the parameters, respectively. The experiments were carried out in a greenhouse at 25±2 °C, 65±5% RH and a photoperiod of 16:8 (L: D) h.

Based on the results, the highest values of intrinsic rate of increase (rm) and net reproductive rate (R0) of the aphid were estimated on Tarom (0.443 ± 0.009 and 30.14 ± 2.05, resp.) and the lowest values were on Caspian (0.297 ± 0.009 and 16.78 ± 1.55, resp.) and Danito (0.305 ± 0.011 d-1 and 16.62 ± 1.60 per generation, respectively). The finite rate of increase (λ) ranged from 1.346 ± 0.013 on Caspian to 1.557 ± 0.015 d-1 on Tarom. The lowest values for mean generation time (T) and doubling time (DT) of the aphid were estimated on Arshia and Tarom cultivars. In the second experiment, the predator exhibited functional response type III on all cucumber cultivars. The attack constant (b) for the third instar C. carnea varied from 0.00121 to 0.00168 and its handling time (Th) ranged from 0.3145 to 0.4596 h on different cucumber cultivars.

Comparison of the biological parameters showed that Tarom cultivar with the highest values of rm and λ is a relatively desirable cultivar for the growth and feeding of A. gossypii. In contrast, Caspian cultivar is less desirable for A. gossypii. Also, according to the parameters of attack constant (b) and handling time (Th), it seems that Caspian and Danito are more suitable cultivars for biological control of A. gossypii than other two cultivars. However, additional studies under greenhouse conditions are needed to provide further details of different cucumber cultivars, A. gossypii and C. carnea.