مریم میردورقی

The dragon's head, with the scientific name Lallemantia sp, is one of the medicinal plants of the mint family (Lamiaceae). Dragon's head is a plant that has various uses due to its medicinal and industrial properties as well as its use in agriculture. This plant is used in sustainable agriculture in arid and semi-arid regions of Iran. Drought is one of the most important issues in the cultivation of medicinal plants in arid and semi-arid conditions. Because one of the factors that may have a significant adverse effect on plant growth is water scarcity. In contrast, the ability of plant species to tolerate water deficit and wet conditions varies, and this characteristic is usually used to identify drought-tolerant species. Dragon’s head ability to produce in dry conditions shows the flexibility and adaptability of this plant in drought stress conditions. In summary, weather conditions greatly impact the production and effectiveness of medicinal plants by affecting the levels of active substances. Changes in sowing dates influence plant density and water availability during growth. Effective irrigation planning, considering factors like water use efficiency, seed yield, and overall water utilization, is crucial for maximizing plant growth and economic performance. By considering weather conditions, adjusting sowing dates, and implementing efficient water management strategies, farmers can enhance water use efficiency, economic performance, and the overall quality of medicinal plant production. Considering the lack of information about the response of different dragon head species in autumn and spring sowing under arid and semi-arid conditions, the present study was conducted to investigate the effect of sowing date on yield and quantitative and qualitative traits of dragon's head (L. iberica) and lady's mantle (L. royleana) in dry and semi-dry conditions. To investigate the effect of planting date on the yield, quantitative and qualitative traits of the dragon’s head (L. royleana and L. iberica) under dryland condition, a factorial experiment was conducted in the form of a randomized complete block design in three replications. The first factor was two types of Lallemantia (L. royleana and L. iberica), and the second factor was the planting date (November 29 and March 8, respectively, as autumn and spring sowing). The results showed that the simple effect of species on the thousand seed weight at the 5% probability level, number of sub-branches was significant, mucilage percentage and mucilage yield at the 1% probability level. So, the number of sub-branches and mucilage percentage in L. royleana increased by 121.7% and 88.6%, respectively, compared to L. iberica. Also, by examining the simple effect of sowing date (autumn and spring), the number of sub-branches increased at the 5% probability level. Plant height, seed yield, biological yield, harvest index, mucilage yield, and water use efficiency increased at the 1% probability level at the autumn sowing date compared to the spring sowing date. In this regard, grain yield and water use efficiency on the autumn sowing date showed an increase of 125.8% and 126.6%, respectively, compared to the spring sowing date. In addition, the mucilage yield and harvest index in the autumn sowing of L. royleana were 271.3% and 36.6% higher, respectively, than the spring sowing of L. iberica. In general, the sowing date of 29 November (autumn sowing) due to the length of the season, favorable temperature, humidity, and sufficient rainfall compared to 8 March (spring sowing) can be considered suitable for both (L. royleana and L. iberica) dragon's head species under dryland condition. In addition, considering the soil salinity conditions in this study and the increase in mucilage of L. royleana species compared to the L. iberica species, it is necessary to carry out additional research in field condition.

Chickpea (Cicer arietinum L.) is one of the most important legumes in the world (Keifer, 2018). After India, Australia, and Pakistan, Iran has taken the fourth rank in terms of chickpea cultivation area, and the decrease in rainfall and especially the plant's exposure to heat and drought stress at the end of the season is the reason for the decrease in crop yield (SabaghPour et al., 2010; FAO, 2018). In general, drought stress and its relationship with the reduction of yield and its components in crops plants can be primarily attributed to the closing of stomata in response to low soil water content, during which the entry of carbon dioxide into the leaf is reduced, and as a result, it causes a reduction in photosynthesis.

In order to investigate the effect of irrigation regimes on the yield and yield components of chickpea (Cicer arietinum L.), an experiment was conducted at the research farm of Shahed University during 2021–2022 as a split plot design in the form of random complete blocks. The first factor is irrigation systems at three levels: 1) supplementary irrigation (Irrigation at two sowing times and before flowering based on 20% available soil water, 2) complete or control irrigation (irrigation based on 20% available soil water), 3) Low irrigation regime (irrigation based on 40% available soil water) is the second factor of autumn (November 15) and spring (March 15) sowing dates. Irrigation was carried out in the form of streams and stacks, and the ends of the plots were completely closed to prevent water from escaping. Data analysis and calculations related to simple Pearson correlation coefficients between traits were performed with SAS (ver 9.4) and SPSS (ver 23) software, respectively, and the average of treatments was compared by LSD test at a statistical level of 5%. The graphs were drawn using Excel software.

The results of the variance analysis of the interaction between irrigation regime and planting date showed that there is a significant difference between the traits of number of branches per plant, number of pods per plant, plant height, number of seeds per plant, harvest index, biological yield and seed yield. The results of comparing the averages also showed the highest number of branches per plant (9.83), the number of pods per plant (30.5), plant height (51.08) cm, and the number of seeds per plant (26.66). The harvest index was 0.48 percent, the biological yield was 4670 kg ha-1, and the seed yield was 2384.17 kg ha-1 for the autumn planting date treatment under the autumn irrigation regime (irrigation based on draining 20% of crop capacity moisture). The highest correlations with grain yield were obtained by traits: plant height (r = 0.986**), number of branches per plant (r = 0.966**), harvest index (r = 0.962**), number of seeds per plant (r = 0.961*), biological yield (r = 0.956**), hundred seed weight (r = 0.933**) and number of empty pods per plant (r = 0.880*).

In general, the results of this experiment indicate that the Low irrigation regime is more efficient than Supplementary irrigation in all traits after the control irrigation regime in autumn sowing. Therefore, the Low irrigation regime is suggested as a low irrigation regime suitable for the conditions of the tested region for the sowing of chickpeas in autumn, and in addition, other autumn sowing dates of this variety should be studied.

Nitrogen is one of the important nutrient elements necessary for the production of agricultural products, but the excessive application of nitrogenous chemical fertilizers and their leaching cause environmental pollution. Crops’ cultivars with high nitrogen use efficiency is one of the environmental friendly aproaches to mitigate this problem.

To evaluate grain yield and nitrogen use efficiency in barley genotypes under low input conditions (without fertilizer application), a field experiment was conducted in research field of the agricultural faculty of Shahed University, Tehran, Iran in 2016-2017 cropping season. Thirty six barley genotypes, purified for three cropping seasons, were planted using simple alpha lattice design with two replications.

The results showed that genotypes; 106, 107, and 68 had the highest grain yield (7963, 7920 and 7900 kg ha-1, respectively), the highest nitrogen use efficiency (58.6, 58.5 and 56.9 kg.kg-1, respectively) and the highest nitrogen uptake efficiency (2, 2 and 2.25 kg.kg-1, respectively). The results of multiple regression analysis showed that the three variables of nitrogen use efficiency, nitrogen uptake efficiency, and biomass yield explained 98.2% of variation in grain yield. Principle component analysis revealed that barely genotypes divided into four groups. The first group included genotypes; 88, 119, 54, 107, and 68 for nitrogen uptake efficiency and nitrogen use efficiency, grain yield and quality. These genotypes are suitable for low input cropping systems to increase nitrogen use efficiency.

The results of this experiment indicated that further investigations are required for recommendation of barley genotypes with higher nitrogen efficiency and grain yield for low input cropping systems.

Due to the increase in world population and the need for food using traditional agricultural methods does not meet the needs of society. The Food and Agriculture Organization (FAO) predicts that by 2050, 60 percent more food production will be needed to feed the world's 9 billion population. This has concerned agroecologists to sustainable agriculture and encouraged them to do more research and design new sustainable agricultural systems. Therefore, the aim of this study was to examine different mixed cropping systems of cereals and evaluation of different drought tolerance indices using a mixture of winter cereals, wheat, barley and triticale and their response to end-of-season water stress in hot and dry ecological conditions.

In order to investigate the grain yield and drought tolerance indices of mixed culture of different cereal genotypes to water stress in hot and dry ecological conditions, an experiment was conducted as split plot design based on a randomized complete block design with three replicates during 2017-2018 cropping year in College of Agriculture and Natural Resources of Darab, Shiraz University. In this experiment, the first factor was irrigation regime in two levels of normal irrigation and water stress and the second factor was ten cropping systems of genotypes (tall barley line EB-95-97, dwarf barley line EB-95-97, dwarf bread wheat line S-92-19, tall bread wheat cultivar Khalil and a cultivar of Triticale called Juanilo) which were grown as double and pure row culture. Double mixed crops included of: dwarf barley- tall barley (one row of dwarf barley + one row of tall barley), dwarf barley - triticale (one row of dwarf barley + one row of triticale), tall barley - triticale (one row of tall barley + one row of triticale), dwarf wheat - triticale (one row of dwarf wheat + one row of triticale) and tall wheat - triticale (one row of tall wheat + one row of triticale) in a 50:50 planting ratio and their pure cultivation.

The results of this experiment showed that the highest grain yield was obtained in tall wheat-triticale mixed culture with 9472 kg ha-1 under normal irrigation and the lowest grain yield was achieved in pure dwarf barley with 3934 kg ha-1 under water stress condition. The results of correlation analysis of drought indices showed that positive and significant correlations were observed between STI (r=0.858**), GMP (r=0.747*) and MP(r=0.801**) with grain yield under water stress conditions. Alos, positive correlation coefficients were observed between STI (r=0.884**), GMP (r=0.922*) and MP (r=0.932**) with grain yield under normal irrigation conditions. The highest SIIG index in this investigation was observed for dwarf barley-tall barley cropping system which had the minimum yield difference in normal and water stress conditions. 3D-graph of cropping systems using SIIG index indicated that cropping systems of pure tall wheat, pure dwarf wheat and tall barley+triticale mixture demonestraed the highest grain yield both in normal and water stress conditions.

Tall wheat+Triticale mixed culture wheat cultivation system under normal irrigation conditions showed a 16% increase in yield compared to the tall wheat pure cultivation system, while it did not show a significant difference with the Triticale pure cultivation system. Some of the mixed cropping systems such as tall wheat + triticale mixed cropping systems produced higher yields that their pure cultivation systems. Alos, it was concluded that STI, GMP, MP and SIIG were the best drought stress indices to evaluate different cropping systems.

Drought stress is one of the major limitations in crop production worldwide. Genotype mixture has been evaluated as a new way to increase yield in different crops. In this study, different genotype mix systems in durum wheat (Triticum durum Desf.) as impacted by drought stress were investigated. The experiments were conducted under normal and water-stressed conditions in the form of randomized complete block designs, each with three replicates,  in the research farm of the College of Agriculture and Natural Resources of Darab, Shiraz University for two years (2016-2017 and 2017 - 2018). Monocultures of four durum wheat genotypes including Shabrang and Behrang cultivars and DW-92-4, DW-94-14 lines and their binary and quadruple mixing combinations were used in the cropping systems. Drought tolerance indices, including stability tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), tolerance index (TOL), yield index (YI), yield stability index (YSI) and a new criterion designated as SIIG (Selection Index of Ideal Genotype) were used and evaluated to identify the best cropping system. Behrang+DW-94-14 cropping system showed the highest GMP, STI and MP values of drought indices, while the highest value (0.890) of SIIG index was identified in the Shabrang+DW-94-14 cropping system. Positive correlations were found among GMP, STI, and MP with YP. Moreover, biplot analysis of these indices using principle component analysis revealed strong positive correlations among GMP, STI and MP while SIIG index was closely related to YSI index. GMP, MP, and STI indices were identified as the best criteria to identify cropping systems in water-stressed conditions. In both normal and water-stressed circumstances, quadruple genotype culture yielded better yields than monoculture and most binary cultures. However, the highest seed yield was obtained in the normal and water-stressed treatments in the Behrang + DW-94-14 cultivation system with an average of 8815 and 7342 kg ha-1, respectively.

The concept of light consumption efficiency is widely used in the analysis of plant growth. Light use efficiency is the amount of dry matter produced (g per square meter) per unit of absorbed radiation (MJ per square meter) by the plant community. Fertilizer management can also play an effective role in increasing the sustainability of production, and one of the main pillars of sustainable agriculture is the use of biological fertilizers in agricultural ecosystems with the aim of eliminating or significantly reducing the consumption of chemical inputs. In a research study, Vejdani Aram et al. (2018) stated that Fertilizer 2 biofertilizer increased the wheat leaf area index by 1.14 to 54%, regardless of the amount of phosphorus chemical fertilizer used. 

In order to evaluate the effects of chemical fertilizer, vermicompost and plant growth promoting bacteria on quantitative and qualitative yields and radiation use efficiency (RUE) of saffron, an experiment was conducted in the saffron research farm of Shahed University, Faculty of Agriculture in 2014-2015.The experiment was performed as a two-factor factorial in the form of a randomized complete block design with three replications. The first factor is chemical nitrogen fertilizer (urea) in three levels of 0, 50 and 100 percentage of the recommended rate of fertilizer based on soil test and the second factor: different types of non-chemical fertilizer in four levels of control, vermicompost (10 tons per hectare), biofertilizer containing Pseudomonas and Bacillus bacteria (PGPR) and a combination of PGPR and vermicompost. It should be noted that the treatments were applied to the saffron plant for year four and this study was conducted in the year fourth. 

In this experiment, the results of the analysis of variance table showed that the main effect of nitrogen chemical fertilizer on the amount of plant dry matter in all three measurement times—the leaf area index in March, the relative growth rate measured in January and March, and the rate of net assimilation—was not significant. In March, light use efficiency, chlorophyll a, chlorophyll b, and total chlorophyll became significant. Also, the main effect of non-chemical fertilizer on total dry matter in all three measurements, plant growth rate, and specific leaf area measured in March was significant. The results showed that the interaction of nitrogen and non-chemical chemicals fertilizers on most physiological growth traits, ecological traits (radiation use efficiency) and photosynthetic pigment traits were significant. However, none of the fertilizer treatments and their interaction on the amount of active ingredient of stigma, number of flowers, fresh weight of petals, fresh weight of stigma and weight of flowers were not significant. Comparison of the mean of interaction showed that the highest amount of chlorophyll b was obtained in 50% and 100% treatments (611 mg/ml) and (569 mg/ml) for nitrogen fertilizer along with vermicompost and biofertilizer treatments, respectively. Also, the highest amount of total chlorophyll in 50% and 100% treatments (1367 mg/ml) and (1301 mg/ml) were related to nitrogen fertilizer with biofertilizer, respectively. The results of total dry matter measurement showed that the use of vermicompost at all three levels of nitrogen fertilizer increased the dry matter content almost at each measurement. The highest RUE (1.027 g/mJ) was related to vermicompost treatment with 100% nitrogen fertilizer, which was not significantly different from most other treatments. 

In general, it can be said that the treatment of non-chemical fertilizers (vermicompost) with 100% nitrogen fertilizer provides much better conditions to improve growth and increase the efficiency of radiation Use in saffron. Therefore, due to the fact that Iran is located in a low-water region of the world, it is necessary to implement and study the effect of different non-chemical fertilizers compared to chemical fertilizers on the quantitative and qualitative performance of saffron under minimal irrigation conditions over several years.

According to the 2030 Document (FAO, 2016), agriculture is facing more challenges today than ever before. More people need food, water shortages, declining land productivity, and declining agricultural labor are increasing the need for sustainable agriculture around the world.Therefore,the aim of this study is to diversify the grain crop system using a mixture of winter cereals,wheat,barley and triticale and their response to end-of-season water stress in hot and dry ecological conditions.

In order to investigate the yield response and yield components of mixed culture of different cereal cultivars to water stress in hot and dry ecological conditions,an experimental split plot design in the form of a randomized complete block design with three replications in the 2017-2018 crop year in the research farm of the Faculty of Agriculture and Darab Natural Resources-Shiraz University.In this experiment,the first factor of irrigation regime in two levels of normal irrigation and water stress and the second factor including ten levels of genotypes(tall barley line EB-95-97,dwarf barley line EB-95-97 dwarf bread wheat line S-92-19,tall bread wheat cultivar Khalil and a cultivar of Triticale called Juanilo) which were grown as a series of alternatives to double and pure row mixture. Double mixed crops as one in a row, including:dwarf barley,tall barley(one row of dwarf barley+one row of tall barley),dwarf barley-triticale (one row of dwarf barley+one row of triticale),tall barley-triticale (one row tall barley+one row of triticale),dwarf wheat-triticale (one row of dwarf wheat+one row of triticale) and tall wheat-triticale (one row of tall wheat+one row of triticale) with a 50:50 planting ratio and pure cultivation including:barley Dwarf, tall barley, triticale, tall wheat and dwarf wheat had a planting ratio of 100:0. According to plant density(400 plants per square meter for barley,450 plants per square meter for wheat and triticale(seeds per plot) and exactly each planting line (before planting according to the weight of one thousand seeds calculated and measured Were placed in separate bags and planted on each stack(including two planting lines) when planting. The final harvest of the crop was done manually after removing the rows. Traits such as 1000-seed weight, biological yield,harvest index, number of spikes per spike, number of spikes per plant, spike length,plant height and grain yield were measured.

The results of this experiment showed that the highest grain yield was obtained in tall wheat-triticale mixed culture with9472kg ha-1 under normal irrigation and the lowest grain yield was achieved in pure dwarf barley with 3934 kg ha-1 under water stress conditions.The results of correlation coefficients under normal irrigation conditions showed that there was the highest positive and significant correlation between grain yield and biological yield under normal irrigation conditions (r=0.847**) and water stress (r=0.792**).

The tall-Triticale mixed wheat cultivation system under normal irrigation conditions showed a 16% increase in yield compared to the tall wheat pure cultivation system,while it did not show a significant difference with the Triticale pure cultivation system. Existence of more vegetation, less weeds, lower shading temperature and consequently higher photosynthesis under water stress and higher yield components in intercropping systems than pure cereals, which together increase the yield.Seeds in mixed cropping systems were different from pure cereals.The decrease in yield in pure crop compared to mixed crop is due to water stress in the grain filling stage.Therefore, mixed cultivation under water stress conditions shows better yields than pure cultivation,which is probably due to the reduction of exogenous competition in mixed cultivation of cultivars.

Durum wheat is one of the major food for human consumption in the world and its growth and production has mainly influenced by drought stress. One of the possible ways of increasing food in a sustainable agriculture is to produce higher yields in the same cropping area. Mixed cropping as one of the methods and examples of sustainable agricultural try to follow the objectives such as ecological balance, exploitation of resources, quantitative and qualitative increase of yield, reduction of damage of pests, diseases and weeds. Reduction of farmer's dependence on pesticides is one of the other main goals in sustainable agriculture. In general, the aim of this experiment is to evaluate the effect of genetic diversity of genotypes on yield and grain yield components under water deficiency conditions after flowering in durum wheat mixed systems.

This experiment was conducted as split plot based on a randomized complete block design with three replicates at Darab College of Agriculture and Natural Resources, Shiraz University, Darab. The factors included of two water regimes after flowering (normal and Water deficiency) and planting systems including pure culture of four durum wheat genotypes (pure culture of DW-92-4 , pure culture of DW-94-14, pure culture of Shabrang, pure culture of Behrang) and their binary mixed culture (mixed culture of DW-92-4+ Shabrang, mixed culture of DW-92-4+ DW-94-14, mixed culture of DW-92-4+ Behrang, mixed culture of DW-94-14+ Shabrang, mixed culture of Shabrang+ Behrang, mixed culture of DW-94-14+ Behrang and quadruple mixed culture of DW-94-14+ Behrang+ DW-92-4+ Shabrang).

According to the results of this experiment, maximum grain yield was observed in the treatment of binary mixed culture of Behrang+DW-94-14 genotypes with an average of 8815 kg ha-1, which did not have a significant difference with the quadruple mixed culture of 4 genotypes in normal irrigation conditions. The minimum grain yield observed in mixed culture of Behrang +Dw-92-4 with the average of 2233 kg ha-1 in water deficiency condition. Also, group comparison of treatments showed that the highest grain yield was obtained in quadruple culture of 4 genotypes with the average yield of 8799 kg ha -1in normal irrigation conditions. The analyses of correlation coefficient in this experiment showed that the highest positive correlation coefficient obtained between grain yield and biological yield (r = 0.76**) in water deficiency conditions. Also, the highest positive correlation coefficient was observed between grain yield and biological yield in normal irrigation conditions(r = 0.90 **).

The use of mixed cropping of different genotypes of durum wheat affected yield and yield components in this experiment. Mixed cropping of genotypes of durum wheat showed the highest yield under normal irrigation conditions compared to water deficiency conditions. Overall, it seems that mixed cropping can be recommended for higher yields potential either under normal irrigation conditions or water deficiency conditions. Keywords: Drought stress, Genetic diversity, mixed varieties

 Durum wheat (Triticum durum) is predominantly grown in the Mediterranean area, the northern plains of the United States, Canada, Europe, and many parts of the Asia.(FAO, 2017).A large part of the wheat cultivated land in Iran is located in arid and semi-arid regions. Due to lack of water resources and consequently stress for plants, wheat yieldis significantly reduced. Unde rstanding the effect of drought stress on grain yield is an effective step in durum wheat production.(Garcia del moral et. al., 2003).

A factorial experiment with 2 factors in a completely randomized design with 3 replicates including durum wheat genotypes and water stress was conducted in the research greenhouse of College of Agriculture and Natural Resources of Darab in 2017-2018. Mixtures of 4 durum wheat genotypes (Behrang, Shabrang, Dw-92-4 and Dw-94-14) were planted in binary and quadruple combinations and pure culture. Plants were treated in two levels of water stress including normal irrigation and water stressed. Plants which went under water stress did not watereduntil the plants showed rolled leaves.
 

 The results of analysis of variance of yield and yield components are shown intable 1. Interactions ofwater stress and genotype mixtures on grain yield per plant, number ofseeds per spike, number of seeds per spikelet, one thousand seed weight were significant at the probability level of 0.01 (p≤0.01).This means that the response of the genotype mixtures to the same water stress was not the same and the amount of these losses due to water stress were higher for some of the genotype mixtures than others. (table 1). The results showed that the highest grain yield obtained in shabrang+behrang genotype mixture at normal irrigation level (8.75 g per plant) and the least grain yield was observed  in DW-92-4 pure crop under water stress conditions.(1.1 g per plant). The highest positive and significant correlation were observed between grain yield andplant height, 1000 grain weightand leaf length (r = 0.443 **) (r = 0.434 **) (r = 0.312 **) respectively.Some researchers revealed that grain yield in mixed crop combination with the same seeding rate is 15 to 23 percent superior to pure crop cultivation.(Nazeri et al., 2004).

 In general, the results indicated that the combination of genotypes under normal irrigation conditions, than pure culture as an agro-ecological method have some, positive effects on grain yield and other agronomical traits.The highest positive and significant correlation was observed between grain yield andplant height, 1000 grain weightand leaf length (r = 0.443 **) (r = 0.434 **) (r = 0.312 **). According to the results of this experiment, it seems that under irrigation conditions, the use of genotype mixtures can produce more yield than pure culture of a genotype in greenhouse conditions.