JOURNAL OF CROPS IMPROVEMENT (JOURNAL OF AGRICULTURE)
Year:2019 | Volume:21 | Issue:3 |Papers Count:7

In order to evaluate water productivity, brix percentage, internode diameter, root dry weight, sugarcane stem height, and chlorophyll content of legume leaves in intercropping of sugarcane with legume plants, an experiment has been conducted in a randomized complete block design with 14 treatments and four replications during 2016-17 at two locations in Ahwaz. The treatments include sole sugarcane, sole soybean, sole cowpea, sole soybean + rhizobium, sole cowpea + rhizobium, sole sugarcane + mycorrhizal, intercropping sugarcane with cowpea, intercropping sugarcane with soybean, intercropping sugarcane with cowpea + rhizobium, intercropping sugarcane with soybean + rhizobium, intercropping sugarcane + mycorrhizal and cowpea, intercropping sugarcane + mycorrhizal and soybean, intercropping sugarcane + mycorrhizal and soybean + rhizobium, and intercropping sugarcane + mycorrhizal and cowpea + rhizobium. Results show that the highest water productivity (4. 46 k/m3), the highest sugarcane stem height (215. 6 cm), the largest internode diameter in the middle (42 mm) and at the bottom (46. 06 mm) of the stem, the highest dry weight roots (187. 8 g), and the highest brix percentage (21. 88 %) of sugarcane stem extract have belonged to intercropped sugarcane + mycorrhizal and cowpea+ rhizobium treatment, which is 31. 61%, 16. 14%, 32. 42%, 28. 35%, 8. 89%, and 8. 31% higher than sole sugarcane. Mycorrhizal symbiosis has been positive in sugarcane, and when mycorrhizal fungi and cowpea are present simultaneously in a treatment, their synergistic effect on the evaluated traits is positive, too.

With the purpose of determining critical time of weed control under conventional and ultra-narrow row spacing conditions of cotton (Gossypium hirsutum L. ) (Khordad cultivar), a field experiment has been conducted as a factorial arrangement in a randomized complete block design with three replications in Sabzevar during the water year of 2015. The studied factors include the conventional cultivation system (70-cm row spacing), ultra-narrow row (20-cm row spacing), and duration of weed interference (0, 30, 45, 60, and 7 days after emergence and during the full season). Results from the experiment show that in ultra-narrow row condition, seed cotton yield losses of 2. 5%, 5%, and 10% are estimated to occur 27. 4, 36. 1, and 44. 7 days after emergence, respectively. Also, under the conventional condition, yield losses of 2. 5%, 5%, and 10% are estimated to occur 8. 1, 13. 5, and 24. 4 days after emergence, respectively. It is proven that the onset of seed cotton yields on lint yield loss occurs earlier (i. e., 46. 3 and 53. 7 days after emergence, respectively) under conventional condition, while under ultra-narrow row condition the onset of seed cotton yield and lint yield loss is postponed to 57. 9 and 65. 9 days after emergence, respectively. Overall, the experiment results show that cotton cultivation in ultra-narrow row spacing under weed interference conditions could provide a better seed cotton yield than conventional spacing.

In order to investigate the physiological responses of chickpea cultivars to supplemental irrigation and super-absorbent polymer use, an experiment has been conducted in the water year 2015, which has employed a split factorial experiment based on randomized complete block design in the research farm of Khorramabad Agricultural Research Center. The factors include supplemental irrigation time in three levels (without supplemental irrigation, irrigation in 50% of flowering, and irrigation in 50% of seed filling) as main factor and cultivars (Arman, Azad, and Greet) and super absorbent polymer (zero, 100, and 200 kg/ha) in the sub plots. Result show that the supplemental irrigation and super absorbent polymer reduce soluble carbohydrates and seed protein, increasing insoluble carbohydrates, chlorophyll a, chlorophyll b, and total chlorophyll. Supplemental irrigation at 50% of flowering stage leads to an increase in 74% of seed yield, compared to dry land condition. The highest seed yield (2179 kg/ha), biological yield (4012 kg/ha), and harvest index (54. 3%) belong to Greet cultivar with supplemental irrigation at 50% of flowering stage as well as application of 200 kg/ha super absorbent polymer. According to the results, in all levels of supplemental irrigation, the use of superabsorbent polymer improves plant growth conditions, consequently increasing the seed yield to a great extent, which in turn rises further by increasing the consumption of super absorbent polymer within supplementary irrigation. By improving physiological traits, associated with drought tolerance, the use of supplemental irrigation method in areas that make this possible, especially if combined with the application of super absorbent polymers, can increase seed yield in chickpea.

In order to investigate the effect of super absorbent polymer and manure fertilizer on water use efficiency of wheat (Triticum aestivum L. ) cultivars under different water deficit conditions, an experimental has been carried out in a factorial layout, based on randomized complete block design with three replications at the research field of West-Azerbaijan (Saatlo station) during 2017-2018. The first factor is irrigation in two levels: normal and drought stress conditions, with the second one being super absorbent polymer 200 kg ha-1, manure fertilizer 40 ton ha-1, their dual application, and the control (i. e., non-application fertilizer). As for the third factor, it deals with wheat cultivars (Mihan, Heidari, and Zarineh). Results indicate that drought stress, compared to normal irrigation, has reduced grain yield, chlorophyll index, harvest index, and relative water content by about 32%, 22%, 24%, and 19%, respectively. Separate applications of super absorbent polymer, manure fertilizer, and dual application of them lead to an increase in grain yield (by 20%, 22%, and 33%), chlorophyll index (by 7%, 8%, and 14%), harvest index (by 8%, 10%, and 15%), relative water content (by 12%, 13%, and 16%), economical water use efficiency (by 20%, 23%, and 35%), and biological water use efficiency (by 14%, 15%, and 24%), in comparison with the control. The highest leaf temperature (33. 10 ° C) is obtained under drought stress and no application of the fertilizer, while the lowest one (21. 99 ° C) belongs to favorable irrigation conditions along with dual application of super absorbent polymer and manure fertilizer. The highest economical and biological water use efficiency (1. 34 kg m-3 and 4. 10 kg m-3, respectively) occur under drought stress conditions as well as dual application of super absorbent polymer, on one hand, and manure fertilizer, on the other. It turns out that Mihan is a superior cultivar for grain yield, harvest index, and relative water content, among all cultivars under two different moisture conditions. The highest grain and biological yields belong to favorable irrigation conditions and dual application of super absorbent polymer and manure fertilizer.

The present study seeks to achieve effective antagonists to the controlling of the disease called greenhouse pepper canola Rhizoctonia damping off, caused by Rhizoctonia solani. The experiments have been conducted based on completely randomized design in the faculty of agriculture and natural resources of Lorestan University during 2016 and 2017. At first, the fungi and biological agents have been isolated and identified from Solanaceae plants rhizosphere. Afterwards, the antagonistic abilities of fungal isolates such as Trichoderma harzianum and Trichoderma virens fungi and Bacillus subtilis bacteria have been studied against R. solani by means of dual culture method. In addition, the study has experimented the antagonistic ability of these biological agents and Trichomix HV biologic fungicides on these fungi under greenhouse condition, with the results showing that both T. harzianum and T. virens species by colonization and sporulation in PDA prevent the fungi growth for 9. 45% and 15. 59%, respectively. Moreover, it has been proven that antagonistic bacteria cause some effects like outpour of the hyphae contents, color change at the tip of hyphae, thinning, and reduction of mycelium to 8. 47%. Furthermore, experimental results under greenhouse condition show that B. subtilis and T. harzianum treatments have had the most positive effects on growth traits, including height and weight (wet and dry) of the root and stem, decreasing the disease severity to 60. 33% and 70. 33%, respectively. Therefore, this paper offers the best antagonistic agents to control R. solani on pepper.

The present study features a factorial experiment for evaluation of salinity stress effect on some growth characteristics of selected pomegranate (Punica granatum) genotypes from regions with saline water and soil. The experiment, itself, is based on completely randomized design (CRD), with two factors: four genotype levels (namely, ‘ Vahshi Babolsar’ , ‘ Narak Lasjerd Semnan’ , ‘ Chah Afzal’ , and ‘ Voshik Torsh Saravan’ ) and five levels of irrigation water salinity (1, 3, 5, 7, and 9 dS/m) with 4 replications in National Salinity Research Center in 2018-2019. Results show that the type of genotype and salinity levels affect the morphological and physiological characteristics and concentration of leaves element nutrient. In all studied genotypes, increasing salinity concentration has reduced all characteristics under the study, including branch height, branch diameter, number of total leaves, green leaves percentage, aerial organs fresh and dry weight, relative humidity percentage, SPAD, and contents of a, b, and total chlorophylls. However, this practice has increased necrotic leaves percentage, downfall leaves percentage, root fresh weight to aerial organs fresh weight ratio, relative ionic percentage, Na+ and Clpercentage, and Na+ to K+ ratio. In case of ‘ Chah Afzal’ and ‘ Voshik Torsh Saravan’ genotypes, the salinity level of 7 dS/m has witnessed an increase in necrotic leaves (by 3. 11% and 23. 98%), downfall leaves (by 1. 05% and 5. 70%), relative ionic (by 5. 87% and 22. 10%), Na+ (by 0. 31% and 1. 29%), Cl-(by 0. 13% and 1. 10%), K+ (by 0. 64% and-0. 07%), and Na+ to K+ ratio (by 0. 09% and 2. 28%), respectively. Also, there has been a decrease of green leaves (by 4. 16% and 29. 78%), number of total leaves (by 2. 62% and 22. 50%), relative humidity (by 7. 50% and 21. 70%), and total chlorophylls (by 8. 9% and 29. 78%) in case of ‘ Chah Afzal’ and ‘ Voshik Torsh Saravan’ genotypes, respectively. Overall, ‘ Chah Afzal’ and ‘ Voshik Torsh Saravan’ genotypes have been recognized as the most tolerant and sensitive genotypes to salinity stress, respectively, with the former (the ‘ Chah Afzal’ genotype), capable of tolerating salinity up to 7 dS/m through maintaining its growth characteristics and increasing potassium uptake against sodium.

When facing different stresses, plants employ antioxidant mechanism. The present research studies the effect of salinity stress, caused by increased amounts of sodium chloride, on the antioxidative system as well as some physiological characteristics of selected pistachio seedlings (Badami-Riz-e-Zarand, Qazvini, Sarakhs, Atlantica UCB1, and Hybrids of Pistacia. vera cv. Badami-Riz-e-Zaarand × P. Integerrima, P. vera cv. Sharakhs× P. Integerrima, P. atlantica Desf. × P. Integerrima). It carries out a greenhouse experiment as a factorial-based on a completely randomized design with three replicates in cocopit and perlite media. The treatments are consisted of four salinity levels (0, 75, 150, and 225 mM NaCl) along with abovementioned root stocks. Salinity stress has been applied in the second year of seedling growth for nine weeks. The study measures some physiological and biochemical traits of the seedlings at the end of the experiment, its results showing that leaf area and total chlorophyll contents have decreased in all treated plants. Accordingly, under salinity stress Atlantica rootstock displays the greatest reduction, and Badami-Riz-e-Zarand, the lowest. Also, the study shows that by increasing salinity levels, the levels of proline, total phenol content, and antioxidant enzymes activity turn out to stand higher in Badami-Riz-e-Zarand × P. Integerrima, Badami-Riz-Zarand, and Qazvini, in comparison to other rootstocks. It seems that a hybrid of Badami-Riz-e-Zarand × P. Integerrima, Badami-Riz-Zarand, and Qazvini rootstocks is more capable of sustaining leaf water and proteins, being therefore more resistant to salinity stress.