فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 54 (تابستان 1399)

Researches related to the evaluation of the effect of the inputs dates back to long ago in Iran. However, due to the diversity and scattering of the various experimental results, it is difficult to reach to a general conclusion. The present study has made use of meta-analysis to overcome such a problem thereby to blend and reanalyze the findings of independent experiments for achieving a single result. To do so, the scientific-research articles published by the researchers from 1996 up to 2017 inside the country concerning the effect of drought stress on the performance, height and number of bolls in cotton were explored. The extend impact of an each trait is the mean difference of the drought stress results compared with control. The diagrammatic results of the drought stress and performance impact sizes showed that all of the stress levels make significant differences in contrast to the evidence treatment (p < 0.001). Moreover, it was made clear in a contrastive investigation of the diagrammatic results of the height and drought stress impact size and the number of the bolls and drought stress impact sizes that there is a significant difference between the evidence treatment and the total mean, the evidence treatment and 41%-55% of the cultivation capacity and the evidence treatment and 25%-40% of the cultivation capacity. The results of the cumulative diagram of the effect of drought stress on performance, height and number of bolls indicated that the majority of the studies fall on the left side of the diagram which is indicative of the adverse effect of the drought stress on the related traits. In addition, the results of the funnel chart demonstrated that the studies performed in Iran on cotton and drought stress are not much precise (bias and low sample volume).

Pumpkin is one of the valuable medicinal plants which have high oil content in its seeds. The response of pumpkin was examined against controlled water deficiency with spraying salicylic acid under field conditions in 2015 and 2016 in split plot experiment based on complete randomized block design. The plants sprayed with 0, 0.5, 1 and 1.5 mM concentrations of salicylic acid at 5-6 leaf stages. After 15 days plants exposed to -0.3, -1.2 and -1.8 MPa water deficiency. Increasing water deficiency reduced RWC, chlorophyll and carotenoids content, plant height, number of nodes and branches per plant, fruit yield, fruit diameter, seed yield, number of seed per fruit and weight of 1000 seeds while it and also increased the diameter of mesocarp especially in -1.8 MPa treated plants. On the contrary, spraying with salicylic acid resulted in significant increase in RWC, chlorophyll and carotenoids contents, plant height, number of nodes and branches per plant, fruit yield, diameter of fruit, seed yield, number of seed per fruit and weight of 1000 seeds. Haghest salicylic acid effect observed at 1.5 mM concentration. Most of traits under study depicated their significant reduction at -1.8 MPa water deficiency, while other traits like leaf water content, plant height, chlorophyll a, b and total chlorophyll content, nodes per plant, number of branches and mesocarp diameter were reduced at -1.2 MPa. On the other hand, seed per fruit was increased significantly at -1.2 MPa as compared to -0.3 MPa water deficiency. The main reason for increment of seed number per fruit was due to reduction in mesocarp diameter and its weight. It seems that water deficiency changed the partitioning pattern of assimilates from fruit and shifted them to seeds against mesocarp or other parts of fruit. Among the yield components, seed number per fruit and number of fruit per land area had the most effect on yield formation. The variation in seed weight was not significant. According to results, pumpkin may considered as a tolerant plant to soil suction till -1.2 MPa, without a significant reduction in seed yield.

Drought is one of the most important factors limiting the growth and yield of plants in many parts of the world. In order to investigate the effects of drought stress and seaweed extract and salicylic acid on some photosynthetic and photochemical traits of white bean plant, a split-factorial experiment based on randomized complete block design with three replications was conducted in 2016-2017 growing season. The experiment was performed in both Islamabad and Khorramabad regions. Main factor consisted of three levels of irrigation (equivalent of 60 mm: Normal, 90 mm and 120 mm of accumulated evapotranspiration from evaporation class A pan. Sub factor consisted of 8 different levels of salicylic acidapplication (0.5 molar), no application of salicylic acid, 4 levels of seaweed extracts (0, 50, 100 and 150 gram) per plot. Results of this study showed that drought stress decreased photosynthesis rate and chlorophyll content, but the salicylic acid increased both the photosynthesis rate and chlorophyll content. Drought stress also increased proline content, ion leakage from the membrane and antioxidant enzymes activities such as catalase, ascorbate peroxidase and superoxide dismutase, while it reduced the grain yield. Application of salicylic acid increased the activity of antioxidant enzymes, but the response to salicylic acid was not similar in various levels of seaweed. The lowest grain yield was obtained from 120 mm evaporation pan (drought stress treatment) and no application of seaweed, and the highest grain yield was obtained from 60 mm evaporation pan (drought stress level) and 150 g seaweed treatments. Application of seaweed enhanced the grain yield production. Application of salicylic acid also increased grain yield up to 4.5%. According to the results of this study, it seems that salicylic acid and seaweed could reduce some negative effects of drought stress.

To study the effects of nitrogen levels on morphophysiological and antioxidants properties of calendula under deferent irrigation regimes a split plot experiment based on a randomized complete block design with three replications was conducted at the Urmia Agricultural Station of Saat Lo for two cropping seasons 2016-17. Treatments were four levels of irrigation (irrigation after 5, 10, 15 and 20 days) assigned to main plots, and application of 0, 80, 160 and 240 kg.ha-1 nitrogen to subplots. Results showed that the effects of irrigation intervals on all studied traits waer significant. There were significant differences among nitrogen levels on all traits except proline content. Interaction of two treatments was significant on leaf area index, stomatal conduction coefficient, chlorophyll b, essential oil percentage, and essential oil yield. Resulats also indicated that, with increasing irrigation intervals from 5 to 20 days, relative water content, chlorophyll, carotenoid, and dry flower yield were reduced by 36.64, 35.27, 24.31 and 45.77 percent respectively. Proline content, catalase superoxide dismutase, and malondialdehyde activities were increased by 24.72, 33.04, 35.51 and 20.86 percent, respectively. Among the nitrogen fertilizer levels, 160 kg ha-1 increased, relative water content, chlorophyll a, carotenoid and dry flower yield by 16.18, 4.24, 23.68  and 28.26 percent, respectively, while it reduced the activity of catalase, superoxide dismutase, and malondialdehyde by 18.10, 21.23 and 29.69 percent respectively as compared to control. The highest leaf area index, stomatal conduction coefficient, chlorophyll b were increased by the use of 160 kg.ha-1 nitrogen fertilizer and irrigation intervals of 5 days. The highest percentage of essential oil of the flower and essential oil yield were also belonged to the application of 160 kg.ha-1 nitrogen and irrigation interval of 10 days. To obtain better quality and higher essential oil yield from calendula, irrigation interval of 10 days and application of 160 kg.ha-1 nitrogen fertilizer is recommended.

Nitrogen and phosphorus are essential nutrients in growth of plants. In addition, the type and method of fertilizer application play an important role in the efficient absorption of nutrients and reduce fertilizer use. Therefore, an experiment was conducted in a randomized complete block design with three replications in the Bahar city in 2017: phosphorus fertilizer was three levels (no application, triple superphosphate and diammonium phosphate), nitrogen fertilizer with two levels (placement and no-placement) and potato cultivar with three levels (Agria, Banba and Sante). The highest leaf area index (5.27), crop growth rate (13.22 g.m-2) and total dry matter (582.86 g.m-2) were obtained from diammonium phosphate along with nitrogen placement in by using Agria cultivar. The results also showed that under conditions phosphorus deficiency, nitrogen application method did not affect leaf area index, crop growth rate and total dry matter: However, tuber yield of Agria under phosphorus deficiency increased by nitrogen placement treatment. In this study, the use of diammonium phosphate, compared to triple superphosphate, increased leaf area index, crop growth rate, relative growth rate and total dry matter. The effect of nitrogen placement along with triple superphosphate was higher than that of nitrogen with diammonium phosphate. Chlorophyll index was not affected by nitrogen placement when using diammonium phosphate, whereas, nitrogen placement increased chlorophyll index by 6.5% with triple superphosphate. The results also showed that the tuber yield increased by 25.4% when nitrogen used by placement combined with triple superphosphate fertilizer. As a whole, highest tuber yields of all three cultivars, especially in Agria and Banba, were increased under nitrogen placement treatment along with diammonium phosphate.

Sorghum (Sorghum bicolor Moench) is one of the most important forage crops in the cereal family. Due to its adaptation to arid condition and high-water use efficiency, it may produce satisfactory seed yields in arid conditions. The present study was conducted in Khorramabad province during two crop years of 2016 - 2017. The experiment was conducted in a randomized complete block design with split-factorial arrangement with four replications. The stress factor was assigned to main plots through three levels of irrigation, normal irrigation, and irrigation at vegetative and reproductive stages, and sub-factor to subplots, consisted of three levels of biofertilizer, soil NPK application, soil vermicompost application, and vermicompost and chemical fertilizer combining with Sepideh and Kimia cultivars. Initially, combined analysis of variance was performed. Due to the lack of significant year effect and its interaction effects by different factors, analysis of variances was performed on two years data. The effects of stress and the interaction effects of cultivar by stress and fertilizer on some traits were measured. It was found that the quantitative, qualitative and phonological indices of sorghum were directly negatively affected by stress at the reproductive stage. On the other hand, the effect of vermicompost fertilizer on the studied traits was significant and positive. Sepideh possessed the highest vahues for those traits except for protein percent, in comparison to Kimia. Grain yield was about 8 ton at irrigation-interrupt during vegetative stage for Sepideh and 4.36 t.ha-1 for Kimia, but grain yield at irrigation-interrupt during reproductive stage was 7.67 and 4.45 t.ha-1 for Sepideh and Kimia, respectively.

Drought is the abiotic stress to decrease yield potential. To screen and identify drought tolerant genotypes of bread wheat landraces, was studied in a randomized complete block design with three replications with two levels of stress (stress and non-stress environments) and 25 bread wheat genotypes, at the Razi University of Kermanshah in 2017-2018. Results of analysis of variance and mean comparison of morphological, physiological and biochemical traits showed that effect of genotype was significant for most of the traits under stress. Correlation coefficients showed a positive and significant result between yield with thousand seed weight and biological yield in both stress and non-stress conditions. Analysis of variance and mean comparisons showed that genotype No. 10 was superior under both stress and non-stress conditions. The results of correlation between drought stress indices showed that STI, MRP and biological yield were positively and significantly correlated with grain yield under both stress and non-stress conditions. Ranking of genotypes, based on sum of ranks, mean ranks and standard deviation of ranks, showed that genotypes 10, 15 and 18 were best rank and recognized as superior drought resistant genotypes, while genotypes 4, 16, and 22 were identified susceptible. Factor analysis in stress environment explained 80.55% of the variance by four main factors. Ward's cluster analysis under stress condition divided the genotypes into four groups. Grouping of genotypes were somewhat different due to different responses of bread wheat genotypes to water deficit stress and their differences in susceptibilies or relative resistancese.

Chickpea (Cicer arietinum L.) is commonly grown under dryland conditions during spring on soils that conserve moisture from the preceding season, in Iran. Seeding rate can have a major impact on production of chickpea. A field trial was carried out at Gerizeh Agricultural Research Station of Kurdistan (35°16’N 47°1’E), west of Iran during 2015-16 cropping season. The trial was carried out in a factorial experiment based on randomized complete block design (RCBD) with three replications. The factor "A" was plant densities, consisting of 15, 25, 35, and 45 plants m-2 and factor "B" was chickpea varieties (Kaka, Pirouz, ILC 482, and Samin). The effect of chickpea varieties and interaction between plant densities and varieties were significant on all measured parameters, except on number of seed per pod, plant height and height of first pod. Also, the effects of plant densities on seed yield, 100 seed weight, leaf chlorophyll index, protein content, plant height, and number of branch per plant were also significant. Results showed that an increase in plant density resulted in significantly higher seed yield per hectare. The mean yields indicated the sensitivity of "Samin" cultivar to high plant population, while it was, suitabilie to cultivar "ILC482" (45 plants m2). "Kaka" and "Pirouz" produce near optimum yields at medium plant densities (25 and 35 plants m-2). Mean yield comparison of cultivar × palnt density showed that cultivars "Pirouz", "ILC482" and "Samin" did not differ significantly in protein content but "Kaka" significantly produced higher protein content the three cultivars. Correlation coefficient for seed yield, number of pods/plant, seed weight, number of branch/ plant and plant height were positive and significant, while for seed yield, and height of first pod were negative and significant. According to the results of the this study Samin, with its large seed size and other desirable characteristics and plant population of 35 plants m-2 can be recommended for planting in Sanandaj and similar climatic areas.