فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 59 (پاییز 1400)

To investigate the effect of foliar selenium nanoparticle applications on the agronomic and yield characteristics of winter oilseed rape, with three levels (0 (control), 25 and 50 mg.L-1) at two growth stages (6-8 leaves and 50% flowering) at the research farm station of the University of Mohaghegh Ardabili during 2018-2019 was studied. The results showed that the selenium nanoparticle applications increased the photosynthetic pigments and the relative water content (RWC) of the leaves significantly. Foliar spraying with 50 mg.L-1 selenium nanoparticle increased in the chlorophyll a and b and total chlorophyll content by 37.04, 44.51 and 39.68%, respectively, as compared to the control treatment. On the other hands, selenium nanoparticle application increased the plant height, number of branches and stem diameter via improving the photosynthetic pigments content and RWC of winter oilseed rape significantly. The biological yield, harvest index and seed oil content of 25 and 50 mg.L-1 of selenium nanoparticle treatments were significantly higher than those of the control. The foliar spraying of oilseed rape plants with selenium nanoparticle applications improved the grain yield throught increase in the number of pods per plant, the number of seeds per pod and the 1000 grain weight significantly. Thus, the highest improvement in the grain yield per unit area (about 34.16 %) was obtained with application of 50 mg.L-1 selenium nanoparticles in comparison with control treatment. In general, the application of 50 mg.L-1 selenium nanoparticles had a positive and significant effect on the physiological (photosynthetic pigments content and RWC) and agronomical characteristics at plants, as to the plant height, branches number, stem diameter, the number of pods per plant, the number of seeds per pod, the 1000-grain weight and seed oil content of winter rape.

To evaluate the effect of nitrogen rate and its split application on seed yield and nitrogrn use efficiency (NUE) of quinoa cultivars, experiments were performed during 2018-2019 and 2019-2020 growing seasons as factor split plot based on randomized complete block design with three repetitions at Khuzestan Agricultural and Natural Resources Research and Training Center Station. Experiment treatments were nitrogen fertilizer (0, 100, 200 and 300 kg.ha-1) as the main factor and four levels of split nitrogen fertilizer applications (50% basic + 50% six-leaf, 50% basic + 25% Six-leaf percentage + 25% mid-flowering, 25% basic + 50% six-leaf + 25% mid-flowering and 25% basic + 25% six-leaf + 50% mid-flowering) and three cultivars of quinoa (Gizat, Q26, Titicaca) as sub-plot. The results showed, SPAD, height plant, number of plant branches, number of panicules per area unit and seeds per panicule as influenced by nitrogen content × split × cultivare, interaction. The years× nitrogen rate×split application× cultivar intractions were significant on plant height, 1000 seed weight, seed yield, biological yields, harvest index and NUE. The highest seed yield under all different levels of nitrogen was related to cultivar Q26, in both years by the use of 200 kg of nitrogen, the highest seed yield in the first year belonged to at 25% base application + 50% at six-leaf stage+ 25% at mid-flowering stage and in the second year, to at 50% as base application+ 25% at six-leaf stage+ 25% mid-flowering stage. Highest NUE belonged to Gizal (52.8 g.kg-1) and Q26 (51.8 g.kg-1) cultvars from 200 kg.ha-1 nitrogen by split applications of 25% base + 25% at six-leaf stage+ 50% at mid-flowering stage, while in second year from 100 kg.ha-1 nitrogen. In general, climatic conditions and split application of fertilizer were effective roles in increasing the efficiency of nitrogen consumption. Thus by the use of proper management seed yield can be increased and the risk of its production decreased.

To investigate the effect of seed priming treatments on seed yield and it’s components in three bread wheat cultivars (Rijaw, Sardari and Karim) was studied under dryland condition at the Agricultural and Natural Resources Research and Education Center of Kermanshah during 2015-2016 and 2016-2017 growing season. The priming treatments consisted of gibberellic acid with 100 mg.L-1, 24-epiprasinolide 1 mg L-1, potassium chloride with 100 mmol L-1 and polyethylene glycol (PEG4000) with -2.3 and -2.9 bar, zinc sulfate 0.1 and 0.3%, 2 and 4 g urea L-1, ascorbic acid 100 mg L-1, hydropriming with distilled water and control (without seed priming). The highest percentage of crop ground cover was obtained with 39.9% of Sardari cultivar and 4 g urea L-1. The highest relative mean water content and flag leaf membrane stability index with 88.1 and 71.6% were related to Karim cultivar with 0.3% hydrated zinc sulfate treatment, respectively. The lowest mean rate of flag leaf water loss (30.6%) was obtained from Karim cultivar with zinc sulfate treatment of 0.3%. Two-year results showed that the highest mean seed yield (2801.4 kg.ha-1) belonged to Rijaw cultivar by seed priming treatment with 4 g.L-1 urea. The highest percentages of seed protein content by NIR method of Karim cultivar and treatments of urea with a concentration of 4 g.L-1 (12.32%), ascorbic acid (12.31%) and gibberellic acid (12.18%) with 100 mg.L-1 were obtained. In this study, based on the total measured traits of morphophysiological, yield and grain quality traits, nutient treatments of urea with a concentration of 4 g L-1, zinc sulfate with a concentration of 0.3% and ascorbic acid with a concentration of 100 mg.L-1 and potassium chloride 100 mmol L-1 were identified and recommended as appropriate and superior seed priming treatments.

To investigate the effect of soluble salicylic acid and micronutrient elements on some of the biochemical and agronomic characteristics of rapeseed under water deficit conditions studied in a split factorial experiment based on a randomized complete block design with three replications at the Faculty of Agriculture, Lorestan University during 2016-2017 growing season. Water deficit was considered as the main factor with two levels (irrigation at 20 (control) and 70% of field capacity depletion), and combined treatments of two factors of foliar application of micronutrient elements (non-consumption and spraying at a concentration of 2 per thousand) and salicylic acid concentration of 0, 0.5, 1 and 1.5 mM) as the subplot. The results showed that the effects of water deficit and salicylic acid on all traits under study were significant. The results showed that triple interaction was also significant on catalase, peroxidase. proline, oil percent, seed yield and oil yield. The highest average oil percentage, seed and oil yield were 46.02%, 4424 and 2036 kg.ha-1 of the treatment combination (no stress+ solubility of 1.5 mm salicylic acid and concentration of 2 per thousand micronutrient fertilizer). The results of this study, based on the changes in the mean, showed that salicylic acid and micronutrient elements reduced the effect of water deficit in canola seedlings. In general, Based on the results of this study, it is recommended to reduce the negative effects of water deficit stress and produce proper seed yield, by using Ferti Mix Trio fertilizer and 1.5mM salicylic acid under water deficit conditions.

To evaluate different irrigation regimes and planting dates on plant height, stem diameter, yield, and yield components of okra (Abelmoschus esculentus L.) a split plot experiment based on randomized complete blocks with three replications was conducted in Karaj during 2017 growing season. Experimental treatments were irrigation intervals (8, 10 and 12 days) as a main plot, and planting dates with three levels (4th, 18th of June and 2th July) as a sub-plot. The results of analysis of variance showed that the main effect of irrigation interval was significant on all traits under study. Planting date treatment had a significant effect only on plant height, stem diameter, number of plant branches, number of plant leaves, number of fruits, fresh fruit yield and dry fruit yield. The interaction of irrigation interval treatment and planting date had no significant effect on the trails under study. The highest chlorophyll concentration (3.68 mg.g-1 FW), plant height (100.4 cm), number of branches (3.1), number of leaves per plant (24.8), number of fruits per plant (10.5) and fresh fruit yield (4023 kg.ha-1) were belonged to the irrigation interval of 8 days. Irrigation interval of 12 days decreased by 30.4, 21.7, 21.3 and 28.4 % in stem diameter, fruit length, fruit diameter and dry fruit yield, compared to irrigation interval of 8 days interval, respectively. The highest plant height (99.2 cm), number of branches (2.5), number of leaves per plant (23.3) and number of fruits (9.77) were observed of June 4th planting date. The highest fruit yield was obtained in June 18th planting. Based on the results obtained it can be concluded that irrigation interval of 8 days is recommended to achieve maximum fruit yield and to shorten the length of growing period, saving in water consumption and maximum yield performance in the Karaj region, the date of 18th June is recommended.

To evaluate the additive effect of intercropping of potato and quinoa, and weed management on yield and quantitive traits of potato, this study was conducted in a split plot experiment based on randomized complete block design (RCBD) with four replications at Jiroft and Kahnooj regions. Weed management treatments (control, without controlling weeds), paraquat herbicide (3 liter per hectare) and manual weeding, were considered as the main plot, and additive intercropping patterns (potato: quinoa in density levels of 5:15, 5:20 and 5:30 plants.m-2) and potato sole cropping (5 plants.m-2) were assigned to sub-plots. Based on the results, intercropping cultivation had significant effects on reducing weed densities and increasing plant height, leaves number per plant, leaf area index, tuber number per plant, tuber yield and marketable tuber yield. Increased densities of quinoa in intercropping cultivation caused an enhancing trend in potato plant height (4.2-9.1 %), leaves number per plant (7.9-16.6 %) and leaf area index (5.6-12.7 %) as compared to potato sole cropping treatment (control). Manual weeding, also decreased in weed density (16.1 %), and increased leaves number per plant (3.7 %), tuber number per plant (9.4 %), tuber yield (6.3 %) and marketable tuber yield (9.8 %) in comparison to that of paraquat herbicide treatment. The highest mean tuber number (7.5 number.plant-1) was observed in the 5:20 intercroping treatment, which resulted in 7.1% increase in the tuber number as compared with the control treatment. Highest tuber yield (4.54 kg.m-2) and marketable tuber yield (4.01 kg.m-2) were also obtained with the 5:20 intercroping treatment under manual weeding at Kahnooj region, and resulted in 69.4 and 20 % increases in tuber yield and marketable tuber yield respectively, as compared with the potato sole cropping without weeding (control treatment) in this region. Generaly, the best results were obtained in potato and quinoa intercropping with density of 5:20 plants.m-2 under manual weeding at Kahnooj region

The use of cultivated plants in the consecutive of cropping systems is one of the most important alternative and sustainable methods to eliminate or reduce the use of herbicides. To investigate the effect of crop residues on weed control and corn yield of NS640 cultivar, an experiment was conducted in 2015-2016 and 2016-2017 cropping years. This experiment was performed in two years and two places in a randomized complete block design with four replications. Two farms with clay- loamy and sandy-loam soil as a place and cultivation of four pre-corn crops including bean-branch (Vicia faba L.), wheat-Chamran (Triticum aestivum L.), rapeseed-Hayula 401 (Brassica napus L.), cabbage - Steady hybrids (Brassica oleraceae L.) and fallow were the treatments. Combined analysis of the results showed that the comparison of weed density and dry weight in different treatments of pre-cultivated plants with fallow (without pre-cultivated plants) showed the potential of pre-cultivated plant residues in reducing and controlling weeds. The reduction in the number of weeds in clay-loam field in the residues of bean, wheat, rapeseed and cabbage pre-cultivation plants compared to fallow were 22, 9, 10 and 29%, respectively, and in sandy-loam field 40, 48, 42 and 46%, respectively. Weed dry weight was significantly affected by crop residues. Bean, wheat, canola and cabbage residues reduced weed dry weight by 54, 55, 43 and 65% compared to fallow, respectively. The use of bean residues as a growing crop in clay-loamy and sandy-loam soils increased corn seed yield by 40 and 55%, respectively. The use of crop residues by higher decomposition of crop residues in the second year and creating a state of soil damage and a negative effect on weed dynamics indices can play an effective role in improving corn growth and increasing the productivity of the cultivation system.

To investigate and determine the limiting factors of wheat grain yield and the contribution of each of these factors in creating wheat grain yield gap, this study was conducted based on the CPA method (comparison performance analysis) in the eastern part of Kerman. Fifteen farms in each at Bam, Narmashir and Fahraj cities, (5 farms in each city) studied for two years (2017-2018 and 2018-2019). In this study, all information related to management, climate and agricultural traits (including 45 variables) were measured and recorded. Using multiple regression method, the relationship between wheat yield and all variables were examined step by step. A production model was determined for management and climate factors. The results showed that there was a gap between the actual yield (farmers' yield) and the potential yield (attainable yield) of 2347.98 kg.ha-1. Irrigation rate, consumed nitrogen fertilizer, spike density and late planting were 51.1%, 36.4%, 7.9% and 4.5%, respectively, involved in creating yield gap. Among the farms studied, the farm located in Firoozabad Fahraj with 6272 kg.ha-1 seed yield had the highest seed yield and the farm located in Dolatabad Fahraj with 1116 kg.ha-1 had the lowest grain yield. According to this research, it seems that with proper management of farms and optimization of limiting factors (Irrigation rate, consumed nitrogen fertilizer, spike density and late planting) wheat yield in Bam, Narmashir and Fahraj regions can be increased by 2347.98 kg.ha-1 as compared to that of the current yields of the farmers, studied.