JOURNAL OF CROPS IMPROVEMENT (JOURNAL OF AGRICULTURE)
Year:2020 | Volume:21 | Issue:4 |Papers Count:9

A field experiment has been carried out to investigate the effect of Persian clover (Trifolium resupinatum L. ) as an undersown cover crop on weed control in winter oilseed rape. The experiment is in a randomized complete block design with four replications in Nahavand region (km: 35) of Iran during 2017-2018. The treatments include oilseed rape with four levels of Persian clover density (25%, 50%, 75%, and 100% of the optimum sowing rate) and two levels of weed management (weedy and weed-free). Results show that the undersown Persian clover has a significant effect on reduction of the density and aboveground dry weight of the weeds, compared to the control. Oilseed rape with 25%, 50%, 75%, and 100% of Persian clover sowing rate causes a reduction by 63%, 66%, 80%, and 91% in weed density. The same treatments also cause 35%, 51%, 58%, and 75% of reduction in weed aboveground dry weight, respectively. Oilseed rape yield undersown with Persian clover has been lower than oilseed rape in weed-free treatment. However, oilseed rape yield in oilseed rape with 75% and 100% of the Persian clover sowing rate has been higher than oilseed rape weed infested treatment. The percentages of oilseed content in oilseed rape in all treatments undersown with Persian clover has been equal to oilseed rape weed free treatment, surpassing oilseed rape weed infested treatment. The land equivalent ratio in oilseed rape with 75% and 100% of Persian clover sowing rate has been 0. 92 and 1. 09, respectively. Therefore, the use of Persian clover as an undersown cover crop in oilseed rape crop could be considered an efficient non-chemical weed management strategy, which may also lead to ecosystem services such as nitrogen fixation and soil organic matter boost.

A factorial experiment has been conducted as a randomized complete block design with three replications at the research fields of Faculty of Agriculture of Tarbiat Modares University, during 2017-2018 growing season. The treatments are consisted of three different levels of salinity stress (control), salinity of 5 and 10 dS. m-1 ), and two levels of calcium silicate (control and foliar application of 8 kg. ha-1 ), wherein salinity stress has been applied from the beginning of flowering and calcium silicate, at flowering time. The paper then evaluates dry weight of the plant, grain yield, yield components, harvest index, oil yield, oil percentage, and greenness. Foliar application of calcium silicate shows positive effects on all traits of both Zarfam and Sarigol cultivars, increasing the yield in rapeseed. On the other hand, it can be observed that Sarigol has had more pods, more seeds per pod, as much as 1000 of grain weight, and greater harvest index, oil percentage, oil yield, and greenness index than the Zarfam, which has had the maximum plant dry weight. In addition, it is observed that salinity stress at 5 and 10 dS. m-1 have negative effects on all studied traits in the present study. In general, salinity stress reduces the yield and yield components of rapeseed and the use of calcium silicate reduce the negative effects of salinity stress in both Zarfam and Sarigol cultivars with the latter showing more resistance to salt stress than the fomer, being used more effectively from calcium silicate.

his study aims at investigating the effect of organic growth stimulator on growth and yield of rapeseed (Dalgan cultivar) under drought in University of Zabol (Chahnime) during 2017 as a split plot experiment, based on RCBD with three replications. The treatments include irrigation cut off levels, based on the phenological growth stages (Sylvester-Bradley encoding system): I1 = control (complete irrigation), I2 = irrigation up to growth rate code 2. 20 (twenty internally identified), and I3 = irrigation to growth rate code 5. 9 (all pods are more than 2 cm long), with the subsidiary factor being consisted of four levels of fertilizer: F1 = control (pure water solution), F2 = Hamoon Green 1 liter at 10 liter + calcium, F3 = Hamoon Green 1 Liter at 20 liter + calcium, and F4 = Hamoon Green 1 liter at 30 liter + Calcium. Results show that I2 has significantly decreased plant height, stem diameter, number of pods, number of seeds per pod, 1000-seed weight, grain and biological yield, and oil percentage, while F2 has increased the abovementioned traits, except for the percentage of oil. Interaction effects show that the highest amount of chlorophyll a, b, total, carotenoid, selenium, and calcium content of grain belong to I1F2, while the highest amount of proline has been observed in I2F2. Also, the highest of these traits belongs to F2. Generally, spraying the organic growth stimulator can moderate the harmful effects of drought stress in rapeseed, improving the seed yield by 27%.

The role of amino acids on root uptake and root-to-shoot translocation of micronutrients is of great importance to improve plant nutrition management. The present nutrient solution culture experiment investigates the effect of the application of 100 μ M tryptophan, arginine, and histidine on the uptake and root-to-shoot translocation of zinc (Zn) and iron (Fe) in rapeseed, supplied with three Zn levels (0, 5, and 10 μ M in the form of zinc sulfate). Results show that at the 5-μ M Zn level, application of arginine and tryptophan significantly reduce the shoot dry weight, compared to the amino acid-free control, while the use of histidine significantly increases the plant shoot dry weight. The highest plant shoot Zn uptake has been found at the 10-μ M Zn plus histidine treatment. Application of this Zn level in the presence of arginine leads to a significant increase in root Zn uptake, compared to the amino acid-free control, while no similar effect could be found in the presence of other amino acids. In the presence of amino acids, with the exception of arginine, increasing Zn concentration in the nutrient solution to 10 μ M results in lower shoot and root Fe uptake in comparison with amino acid-free treatment. In contrast, at 10-μ M Zn treatment, application of arginine enhances plant shoot and root Fe uptake. The highest concentration of total amino acids in the plant shoots and roots belong to the free-Zn and free-amino acid treatments. Regardless of the type of amino acid used, increase in the Zn level up to 10 μ M raises the leaf activity of the catalase (CAT) and ascorbate peroxidase (APX). Based on the results, the presence of amino acids, dependent on the amino acid type, has had a significant effect on the root uptake and root-to-shoot translocation of zinc and iron in rapeseed. Among the amino acids, histidine is responsible for the highest increase in the plant shoot and root Zn uptake as well as dry matter yield.

In order to study the effects of methanol and humic acid on physiological traits, yield, and water use efficiency in chicory under drought stress conditions, a split factorial layout based on a randomized complete block design has been conducted with three replications in a field of Islamic Azad University, Birjand Branch at 2015, with three irrigation levels (irrigation after 70, 140, and 210 mm cumulative evaporation) as main plots and methanol spraying at two levels (zero and 21 percentage volume) and humic acid with two levels (zero and 10 L. ha-1 ) as sub plots. The studied traits include chlorophyll index, stomatal conductance, leaf relative water content, dry weight of root, stem, and leaf, dry yield of total, root to stem and leaf ratio, water use efficiency of root, stem and leaf and total. Results show that water defficit stress has reduced all physiological and yield traits (except root to stem and leaf ratio), increasing water use efficiency of chicory. Also, foliar spraying of methanol raises all traits (with the exception of yield and water use efficiency of root). The application of 10 L. ha-1 humic acid increases all traits (except for the ratio of root to air organs). The highest dry matter production (710. 7 g. m-2 ) belongs to irrigation after 70 mm evaporation from the pan and application of 10 L. ha-1 of humic acid, whereas the highest water use efficiency for dry matter production -3 (0. 99 kg. m ) is obtained from treatment of irrigation after 140 mm evaporation from the pan and application of 10 L. ha-1 of humic acid. In general, based on the results, irrigation treatment after 140 mm evaporation from the pan and humic acid at 10 liters per ha can be used to achieve an acceptable chicory yield along with water economy in Birjand region.

In order to investigate the effect of biochar and biological fertilizer on photosynthetic pigments, yield, and nutrient content of peppermint (Mentha piperita L. ) an experiment has been conducted as factorial, based on a randomized complete block design in three replications at Sari Agricultural Sciences and Natural Resources University in 2017. The treatments include biochar on two levels (0 and 10 ton ha-1 organic and biological fertilizers on five levels (no fertilizer (F0), vermicompost (10 ton ha ) and -1 ) (F1), Pseudomonas fluorescens (F2), Azotobacter (F3), and Arbuscular mycorrhiza (Glomus mosseae, G. intradicces, and G. etunicatum) (F4)). Results from this study show that the use of biochar increases the chlorophyll a and chlorophyll content by 7. 42% and 9. 71%, respectively. Among fertilizer treatments, the highest amount of chlorophyll belongs to vermicompost (6. 11 μ g. ml-1 ), significantly better than other treatments. In addition, the main effect of biochar and bio-fertilizer have had a significant effect on leaf, stem, and total fresh weight of the plant. Results from comparing mean of fertilizer treatments show that the highest leaf fresh weight, stem fresh weight, and total fresh weight per square meter belong to the treatment of mycorrhiza (306. 08, 361. 15, and 663. 03 g. m-2 respectively). Also, the use of biochar increases the leaf fresh weight, stem fresh weight, and total fresh weight (294. 78, 366. 73, and 661. 46 g. m-2 respectively), compared to the conditions without using it. Based on the results of the comparison of the mean of the main effects, all treatments increase nitrogen content, compared to the control. The highest nitrogen content (1. 83%) is related to Azotobacter treatment, not significantly different from vermicompost, mycorrhiza, and Pseudomonas. Results also suggest that the maximum amount of phosphorus (0. 37%) have been seen in biochar + mycorrhiz and biochar + vermicompost. Therefore, with respect to the production of medicinal plants in the low-input cropping systems, it is recommended to protect the environmental and achieve sustainable agriculture to improve plant growth and photosynthesis of peppermint application of biochar + mycorrhiz along with biochar + vermicompost treatment.

This study has been conducted to compare the growth characteristics of three species of Alyssum minus, A. szwitsianum, and A. desertorum over two years of 2017 and 2018 in a randomized complete block design with three replication at Isfahan Agricultural and Natural Resources Research and Education Center. The measured traits include yield characteristics such as total dry weight, leaf, stem, root, and seed dry weight; morphological characteristics like plant height, maximum and minimum plant diameter, plant cover, and stem number; and phenological characteristics such as the number of days to flowering, seeding, and seed ripening. The highest biological and seed yield belong to A. minus, equal to 1003 and 375 kg/ha respectively, while A. desertorum shows the lowest rates, i. e., 559 and 207 kg/ha, respectively. Morphological traits analysis demonstrate that A. minus has had the highest rates of plant height, stem number, plant diameter, and cover. A. minus and A. desertorum with 101 and 95 days to seed ripening have the longest and shortest lifelong species. The highest correlation rates between seed yield with other characteristics have been biological yield (0. 90), plant height (0. 79), stem number (0. 76), and cover (0. 75). Overall, results from this study show that A. minus has displayed the highest yield potential among the studied species.

In order to investigate the effect of pea cultivars and planting pattern on yield and seed protein of pea, total yield, and LER, a factorial experiment (two factors) has been conducted in a randomized complete block design with three replications in research farm of Gonbad Kavous University during 2016-2017. The experiment has used two cultivars of pea (Poffaki (Aspersion) and Shamshiri (Swordfish)) as well as a native variety of spinach, with nine planting patterns, including sole pea and spinach, replacement series of 33%, 50%, and 67% spinach instead of pea, and additive series of 33%, 50%, 67%, and 100% spinach to pea. The effect of pea cultivar and planting pattern have been significant on most traits. Plant length, 100-seed weight, pod weight, pod yield per plant, fresh weight of pea plant, and pod yield in Poffaki surpass those of Shamshiri; though, number of pod per plant and harvest index in Shamshiri are higher than Poffaki. Number of pod per plant, pod weight, pod yield per plant, 100-seed weight, harvest index, and fresh weight of pea in sole pea and replacement series also surpass those of additive series. Addition of spinach in additive series reduces pea traits, while increasing total yield. According to the results, yield of Poffaki cultivar has been 11. 81% higher than Shamshiri and the highest total yield (30. 1 ton/ha) has been obtained from additive series of 100% pea + 100% spinach. Land equivalent ratio (LER) has been over 1 in all intercropping treatments, indicating the superiority of intercropping.

Salinity is one of the problems citrus production faces around the world, and the tolerance or resistance mechanism of citrus rootstocks to salinity is not well known. This study investigates the physiological responses of four citrus rootstocks, namely Sour orange (Citrus aurantium L. ), Poncirus (Poncirus trifoliate Raf. ), Citromelo (Citrumelo), and Citrange (Citranges), to salinity stress in a factorial experiment, based on completely randomized design under in vitro conditions. The explants are prepared from all four rootstocks and transferred in a Murashige and Skoog (MS) solid culture medium, containing 8. 9 μ M BA and 0. 5 μ M NAA with different concentrations of sodium chloride (0, 50, 100, and 200 mM) in three replications. Based on the obtained results, fresh and dry weight of plantlets, water content, leakage, and photosynthetic pigments such as chlorophyll a, chlorophyll b, and carotenoid have had a negative correlation with salinity concentration and concentration of sodium ion in the tissue of the leaves. Although leakage increases by increasing concentration of sodium chloride on all four rootstocks, the sour orange rootstock statistically showed the least leakage as compared to other rootstocks. In all salinity treatments, the amount of rootstocks photosynthetic pigment reductions has been statistically significant (p ≤ 0. 01) in comparison to the control. Among the tested rootstocks, the amount of photosynthetic pigments in the Citrange rootstock surpassed that of other rootstocks. In conclusion, Citrange and Sour orange rootstocks show better resistance to the damages, caused by salt stress.