amir hossien shiranirad

Drought stress is one of the most impactive factors of Severe modification in plant physiology, eventually leading to a reduction in crop productivity. Increasing growth, yield, crop quality, and reducing the side effects of drought stress are some of the important roles that potassium silicate plays in plants. In order to study the effects of late-season drought stress and foliar application of potassium silicate on yield and yield components of spring genotypes of canola, a factorial split-plot experiment was conducted in Karaj, Iran in a randomized complete block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG×AL, RGS×SLM, DALGAN, RGS003 and RGS×Okapi in subplots. The authors found that the interaction impact of irrigation, the application of potassium silicate foliar, the genotype of the number of pods per plant, the number of seeds per pod, the yield of seeds, the level of leaf proline, the glucosinolate and the temperature of the canopy were significant. It is proposed that OG×AL genotype be used in regular irrigation and application of potassium silicate and in late-season dry conditions and in the application potassium silicate of RGS×SLM and DALGAN genotypes.

Drought is a restriction in crop production in arid and semiarid regions. It is forecast that climate change may cause droughts shortly. After oxygen, silicon (Si) is the second most common element in the soil. In reducing both biotic stress (e.g., plant diseases and pest damage) and abiotic stresses such as salinity, drought, aluminum toxicity, heavy metal toxicity, nutrient imbalance, lodging, radiation, high temperature, wounding, and freezing.

In order to study the effects of terminal drought stress and foliar application of potassium silicate on yield and canola spring genotypes components, a factorial split-plot test was conducted in Karaj, Iran in a full randomized block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG × AL, RGS × SLM, DALGAN, RGS003 and RGS × Okapi in subplots. SAS Ver 9.1 statistical analysis was used for variance analysis.

Combined variance analysis showed that the impact of the year on some characteristics seed number in silique, silique length and seed yield was significant. Also, the effect of irrigation was significant on seed yield. The effect of genotype on plant height was significant indicating that the genotypes had different reactions. The interaction effect of irrigation × genotype on Harvest index was significant. The interaction effect of Irrigation × Potassium Silicate × Genotype on branch number, silique number, silique length, seed number in silique, seed weight, biological yield, seed yield, oil content and oil yield was significant. The mean comparison of irrigation and Potassium silicate interaction demonstrated that the most grain yield was observed in normal irrigation and the least value related to cut off irrigation at pod formation stage. The results indicated that, irrigation, foliar application of Potassium silicate and their interaction had significant effect on growth and agronomic traits and increased them.

Finally, our study showed the beneficial effects of Potassium Silicate in improving the drought tolerance of canola plants, especially at the end of the season. This can provide a basis for attempting new strategies to reduce the damage from drought and create a functional link between the role of silicon, physiological response and tolerance to drought stress in canola plants. According to the results, in the case of application of Potassium Silicate and normal irrigation, the promising genotype of OG×AL, with the highest seed and oil yield, is recommended as standard. Also, in the case of application of Potassium Silicate and late-season drought stress (restricted irrigation from the pod formation stages), RGS × SLM and DALGAN with the highest seed yield, is recommended.

Understanding how a weed community is affected by ecological، agronomic and management factors is one of the most effective ways to control and establish management programs for each crop. In order to conduct weed mapping and study the weed population indices of weeds in corn fields of Kermanshah Province، 48 corn fields in different cities based on planting area were selected for sampling during 2010. After sampling the weeds based on standard methods، the weed population indices based on equations were calculated. Using geographic coordinates of field and weed data، a map for each weed species using GIS was produced. To evaluate the similarity of different cities of the province for weed species diversity and evenness، the cluster analysis method was used. The results showed that the dominant broadleaf weed species of Kermanshah Province were redroot pigweed (Amarunthus retroflexus)، common lambsquarters (Chenopodium album)، field bindweed (Convolvulus arvensis)، Chinese lantern (Physalis alkekengi) and common purslane (Portulaca oleracea)، respectively. The dominant grass weeds of Kermanshah Province were green foxtail (Setaria viridis)، Johnson grass (Sorghum halepens) and barnyardgrass (Echinochloa crus-galli)، respectively. Phytosociological studies on weeds in corn fields showed that، according to the Shannon-Wiener diversity index، Kermanshah’s cities were grouped into three clusters. Comparisons performed using the t-test showed that the diversity of cities of the province also have significant differences. The results of the Simpson similarity index showed that Ghasreshirin and Guilan-e-Gharb had the most common species (SQ=0. 82)، while Kerend City along with Ghasreshirin and Guilan-e-Gharb had no common weed species with the lowest similarity. Based on similarities and differences derived from weeds of corn fields in different cities، population parameters for the management of weeds in corn fields were developed and implemented using the same recipes.