نشریه پژوهش های کاربردی زراعی
پیاپی 135 (تابستان 1401)

Plant Protection Organization (PPO) has registered fourteen commercial herbicides formulations for weed control of corn in Iran (Nourbakhsh, 2021). Among these herbicides, eight herbicides contain one active ingredient and the other six have two or three active ingredients including acetolactate synthase (ALS) enzyme inhibiting groups - similar-auxin groups, photosynthetic inhibitors of photosystem II and inhibitors of fatty acids and cell division, which are sometimes formulated with safeners. Weed species do not similarly respond to herbicides and previous studies showed some existing inherent tolerance, causes the percentage control of some of the weed species being lower than the others (Hadizadeh, 2016). Thus, new herbicides with several active ingredients are suggested to be used to suppress such weeds. The aim of this work was to find the best chemical treatments against weeds in corn production based on using new herbicides dicamba+ mesotrione+ nicosulfuron and comparing their efficacy with the common newly or some of older registered herbicides in the major corn growing areas of Iran.

A field study was conducted in four regions of Iran, including Mashhad, Ahwaz, Zarghan and Kermanshah during 2019 growing season. The statistical layout was a completely randomized block design with four replicates. Seven chemical treatments were mesotrione+s-metalachlor+terbuthylazine (Lumax® 537.5SE post-emergence, 4.5 l ha-1), nicosulfuron+rimsulfuron (Ultima® 75%WG, 175 g ha-1), topramezone (Clio® 29.7%SC, 150 ml ha-1), thiencarbazone+isoxaflutol+cyprosulfamide (Adengo® 46.5%Sc, 440 ml ha-1), and the new herbicide dicamba+mesotrione+nicosulfuron with five recommended doses (Calisto Solid 569.5 WG, 400, 500, 600, 700 and 800 g ha-1). A hand-weeded treatment and an unweeded treatment served as controls. Weed density and weed dry weight for each plot were measured four weeks after the last application the herbicides. Corn was harvested from 10 m2 of each plot after removing border plots. Corn grain yield was determined after adjusting the moisture level of grain to 14 %. To measure corn biological yield, samples of 10 corn plants were taken and then were dried in an oven. Data from each region were subjected to statistical analysis using SAS/STAT statistical software and the means were separated by LSD (α=5%).

The results showed a diverse spectrum of weeds (18 species) at the experimental locations. Pigweed species (Amaranthus spp.) were present in all tested locations but were not dominant in Ahwaz. The next dominant weed species were Portulaca oleraceae L. and Chenopodium album L. in Mashhad and Zarghan; Physalis divaricate L. in Ahwaz and Zarghan, Convolvulus arvensis L., Echinochloa crus-galli (L.) P. Beauv., and Corchorus olitorius L. in Ahwaz; Hibiscus trionum L., in Mashhad; Glycyrrhiza glabra L. and Xanthium strumarium L. in Kermanshah and finally Sorghum halepense (L.) Pers., was dominant in Zarghan. Across the experimental locations, dicamba+mesotrione+nicosulfuron was efficient at 700-800 g ha-1 application doses for weed control (75 to 88%). However, when applied at dosage of under 700 gl ha-1, its weed control efficiency was lower (50 to 70%). Topramezone and nicosulfuron+rimsulfuron were inefficient in controlling weeds in all the locations. In contrast, thiencarbazone+isoxaflutol+cyprosulfamide was among the most efficient treatments wich these findings are in agreement with the results of some previous studies (Hadizadeh et al. 2015; Hadizadeh et al., 2020). E. crus-galli was identified as the most difficult-to-control weeds and G. glabra and P. oleraceae were the next ones. None of doses of new herbicide showed injury symptoms on corn.

Dicamba+mesotrione+nicosulfuron (700 and 800 g ha-1) showed 70-85 weed control efficiency averaged in the all experimental locations and it could be recommended to be used in corn field after registration process. Due to environmental concern, it could be applied at lower doses when difficult-to-control weeds were not present. Thiencarbazone+isoxaflutol+cyprosulfamide was found to be the high efficient herbicide. Barnyard grass, licorice and common purslane were difficult-to-control weed species or there were not controlled by new herbicides. We also suggest evaluation of the herbicides for their residual effects on the succeeding crops.

Salt stress affects 20% of global cultivable land and is increasing continuously owing to the change in climate and anthropogenic activities. Globally, wheat is cultivated on non-saline and saline soils, covering an area of approximately 214.79 million hectares (Becker-Reshef et al., 2020). Salinity stress negatively affects the growth and development of wheat leading to diminished grain yield and quality. For this reason, it is important to develop effective strategies to improve yield through salt tolerance. The breeding of salinity-tolerant cultivars through selection and breeding techniques is one of the effective methods in the production and exploitation of saline soil and water.

In order to study the effects of salinity stress on grain yield, phenological and morphological traits and salinity tolerance indices among bread wheat elite lines, two separate experiments in a randomized complete block design with three replications were conducted in two saline and normal environments during two cropping years of 2019-2021. 20 wheat cultivars and elite lines cultivated at the South Khorasan Agricultural and Natural Resources Research and Education Centre. After determining the grain yield in both conditions, MP, GMP, TOL, HARM, STI and SSI indices were calculated and using SAS software, their correlation with grain yield was investigated and using STATISTICA software, the three-dimensional distribution of each cultivar and line was plotted. Combined analysis of variance was performed to determine the main and interaction effects in the two years of the experiment and the means were compared by Duncan's multiple range test at the level of 5% probability. Bartlett's uniformity test was performed before the combined analysis of variance. Analysis of variance and mean comparison was performed using SAS-9.0 software and cluster analysis was performed by Ward method through StatGraphics program.

The reaction of wheat lines were different in two environments and salinity stress reduced grain yield. The experimental results showed that different wheat lines react differently to salinity stress. Salinity stress decreased grain yield and morphological traits in all lines compared to normal conditions. Salinity stress shortens intermediates and reduces plant height and consequently leaf and shoot dry weight by reducing cell proliferation and reducing dry matter accumulation (Dura et al., 2011).The difference between cultivars and lines in terms of all phenological, morphological and grain yield in two years of the experiment was significant, which indicates the existence of appropriate diversity in the wheat elite lines. The existence of this genetic diversity can be very useful for selecting high-yielding wheat cultivars in salinity conditions. In the first year of implementation, Narin, line No. 3 and Barzegar with an average of 6494, 6227 and 6072 kg/ha, respectively, in normal conditions and Barzegar, line No. 18 and Narin with an average of 6361, 6166 and 5805 kg/ha respectively, had the highest grain yield under salinity stress. In the second year of the experiment, line number 16, 10 and 4 with an average of 5388, 5305 and 5155 kg/ha in normal condition and Narin, Barzegar and line No. 3 with an average of 4930, 4611 and 4180 kg/ha respectively, had the highest grain yield under salinity stress. Naturally, wheat lines grain yield under salinity stress was lower than their yield under normal conditions. Under these conditions, the plant leaf area of is greatly reduced, which reduces the photosynthetic capacity of the plant, and as a result, the amount of dry matter produced and ultimately the grain yield of the plant is reduced (Munns et al., 2002).

For selecting wheat cultivars and lines in the areas that are most exposed to salinity stress, YI, HM, GMP, STI, MP, RSI and YSI indices and in areas not exposed to salinity stress, MP and STI indices are suggested. Barzegar and Narin check cultivars and line number 10 were determined as the most tolerant and lines No. 14, 13 and 20 as the most sensitive lines to salinity stress by different indices. Cluster analysis of lines based on STI index led to the placement of Barzegar and Narin cultivars and lines No. 3, 4 and 18 in the first cluster in which the mentioned lines have fewer days to heading and in contrast more days to maturity, grain filling period, thousand-grain weights and higher grain yield.

Kurdistan province has the country's highest area under cultivation and dryland wheat production. A study of factors that can increase the yield of dryland wheat will increase the stability of wheat production in the country. Proper nutrition of dryland wheat is one of the most critical forgotten managements in dryland farming. In the dryland area of Iran, deficiency of some elements, such as zinc, due to high acidity is observed to a large extent (Malakouti & Nafisi, 1997). The foliar application of nutrients is one of the most effective tools for resolving nutrient deficiencies in dryland crops (Liu et al., 2020). This method provides nutrients to the crop with relatively high efficiency and speed (Noulas et al., 2018). Therefore, the present study was conducted to investigate the effects of foliar application of various organic and inorganic compounds on physiological characteristics, yield, and yield components of dryland wheat (cultivar Azar 2).

Two field experiments were carried out during the 2018-2019 and 2019-2020 cropping seasons. The experiments were performed based on a randomized complete block design with eight treatments and four replications on dryland wheat (cultivar Azar 2) in Zarrineh city, 20 km from Divandere city, belonging to Kurdistan province. Foliar application treatments used in this study included: 1- Control (C, placebo) 2- Vitaspirin (V, 1 per thousand) 3- Humic acid (HA, 1 per thousand), 4- Zinc sulfate (ZS, 3 per thousand), 5- Vitaspirin + Humic acid, 6- Vitaspirin + Zinc sulfate, 7- Humic acid + Zinc sulfate, 8- Humic acid + zinc sulfate + Vitaspirin. Foliar application treatments were applied in Stages of stem elongation and heading.

In the 2018-2019 season, the foliar application of ZS, HA, HA+ZS, V+ZS, and V+HA caused to increase in the total chlorophyll content. While the biological yield was only affected by the foliar application of V+ZS in the 2018-2019 season, in the 2019-2020 season, the foliar application of V, V+HA, HA+ZS, V+ZS, and V+HA+ZS caused a significant change the amount of this trait. In the 2018-2019 season, the number of spikes increased due to the foliar application of HA, V, and V+ZS, and in the 2019-2020 season, this trait was influenced by the foliar application of V, V+HA, V+ZS, and, V+HA+ZS treatments. In the 2018-2019 season, thousand kernel weight was only affected by foliar application of V+ZS and V+HA+ZS, but in the 2019-2020 season, V, HA, V+HA, V+ZA, A+ZA, and V+HA+ZS treatments also affected the amount of this trait. As a result of these effects, yield in the 2018-2019 season was only affected by V+ZS treatment (14.04% increase), but in the 2019-2020 season, foliar application of V, HA+ZS, V+ZS, V+HA, and V+HA+ZS treatments increased grain yield by 22.13%, 29.63%, 27.07%, 26.57%, and 20.7%, respectively.

This experiment showed that among the compounds used, foliar application of V+ZS significantly increased grain yield in both cropping years (14.04% in 2018-2019 and 27.07% IN the 2019-2020 seasons). It seems that yield changes were due to the effect of different foliar application treatments on chlorophyll content, spike number, thousand kernel weight, and biological yield. Compared to the control (placebo treatment), the foliar application of V+ZS caused to increase in chlorophyll concentration, spike number, thousand kernel weight, and biological yield by 25%, 7.1%, 5.5%, and 14.04%, respectively, in 2018-2019 season. In the 2019-2020 season, the foliar application of V+ZS improved spike number (6.55%), thousand kernel weight (10.74%), and biological yield (16.92%) compared to the control. Overall, the results of this study showed that the combination of vitaspirin and zinc sulfate could improve the yield of dryland wheat fields. Due to easy access and relatively reasonable prices in the market will be recommended to farmers.

Local rice cultivars have decreased their purity, and yield due to continuous cultivation. Recognition and production of high and stable yield cultivars are one of the goals of achieving new cultivars (Gravois, et al., 1991). The reaction of the different genotypes in different environments, and thus evaluation of genotype interaction in the environment helps plant breeders to evaluate genotypes more accurately and select the best one (Finlay & Wilkinson, 1963). Due to severe drought, late ripening, disease susceptibility, and very low yield of local rice cultivars, achieving new high-yielding cultivars that are cold tolerant and adaptable, and stable in cold regions has been one of the important goals of this activity. The introduction of new 53 line can be suitable for cold and temperate cold regions of the country.

The 97 rice lines were planted in 2008 with local control cultivars in Yasuj Agricultural Research Station in a preliminary experiment. 15 lines were selected based on important agronomic characteristics. Then they were compared in a randomized complete block design, and were selected 4 lines 53, 71, 32, and 39. The lines were evaluated in two regions for two years for compatibility and performance stability. A combined analysis of variance was performed to determine the genotype interaction. Before combined analysis, the Bartlett test was used to correct the homogeneity of variance of years and places. From the method proposed by Eberhart & Russell (1966) and environmental variance stability criteria, Wricke (1962), Shukla stability variance (1972), and Francis & Kannenberg (1987) environmental change coefficient, stability analysis was performed to determine compatible cultivars.

A simple analysis of variance showed genetic differences among the genotypes. The combined analysis of variance was performed after the Bartlett test, the combined analysis of variance indicated the significant effects of genotype, location and interactions of genotype × location, and genotype × year × location. The mean grain yield of genotypes showed that out of 97 studied genotypes, 4 genotypes produced higher yields than the average yield of genotypes in all environments. So that the highest grain yield was seen in genotypes 53 and 71, followed by genotypes 32 and 39. According to the calculation of the mean of genotypes, the highest grain yield was related to genotypes 53 and 71. The lowest environmental variance had the control cultivar and genotype 53. Control cultivar and genotype 53 had the lowest coefficient of environmental change, so these genotypes had the maximum stability of grain yield. The lowest stability variance and as a result the highest compatibility and yield stability were related to control cultivar and genotypes 53. The results showed that genotype 53 had the lowest mean squared deviation from the regression line, the lowest stability variance, and the lowest environmental variance among the promising lines and this genotype had the highest stability in different environments compared to other genotypes. In general, based on all methods of genotype 53 stability parameters, due to high average yield in different regions, yield stability and suitable environmental adaptation are identified as superior genotypes. The results of recording blast disease showed that 53 line was resistant and local cultivars were sensitive. In the research-extension design, the average yield of line 53 in all regions was higher than other lines and control cultivars. Line 53 for one week to ten days earlier than the control cultivar. The results show that line 53 is among the very good quality lines in terms of grain cooking quality. And having 72.4% of total conversion and 52.2% of healthy rice has good conversion quality.

The new genotype (line 53), gave a high average grain yield and was also stable. This line has always been selected as one of the top lines under all experimental designs and conditions such as preliminary, advanced, compatibility, and stability. In general, line 53 with high yield, early ripening, blast disease resistance, stability in the study areas, and very suitable quantitative and qualitative characteristics of grain, was introduced to the agricultural community as a variety of Setayesh rice in 2021.

Maize (Zea mays L.) is one of the most important grains in Iran and across the world with a large cultivation area. This crop plays a vital role in industry, human nutrition and animal feed. The relationship between conservation agriculture and tillage methods and nitrogen application is critical to better understanding their role in agro-ecosystem yield. For successful production, tillage systems are one of the essential operations in corn cultivation (Fathi and Zeidali, 2021). Nitrogen is one of the most important nutrients for crops, especially corn, which, if not consumed in sufficient quantities, can limit plant growth. It has been reported that higher or lower nitrogen consumption has a negative effect on crop growth and production (Taheri et al., 2021). There are plenty of attempts to investigate the combining effect of the conservation tillage methods (including reduced or no-tillage) with nitrogen fertilizer application and previous crop residues. This combined strategy could be recommended as one of the most effective approaches to improve maize performance and achieve sustainable agriculture (Kihara et al., 2011). Accordingly, considering the importance sustainable agricultural, it is essential to optimally use nitrogen and also improve soil properties. Therefore, this study aimed to investigate the effect of tillage and nitrogen combined methods on quantitative and qualitative characteristics of corn.

Materials and Methods:

This experiment was performed as a split plot experiment based on randomized complete block design with three replications in 2017-2019 in Darreh-shahr city, Ilam province. Experimental treatments included three levels of tillage including conservation tillage (using compound tillage and farrower), conventional tillage (once reversible plow + once disc + farrower) and intensive tillage (double reversible plow + twice disc + farrower) as the main plot and chemical fertilizer Nitrogen at five levels included no chemical fertilizer application, 50, 100, 150 and 200 kg N ha-1 as sub-plot.

The results showed that the highest grain yield (7615.9 kg ha-1) was obtained in conservation tillage treatment which showed an increase of 22.3% and 5.8% compared to intensive and conventional tillage, respectively. Also, application of 200 kg ha-1 of nitrogen fertilizer had the highest grain yield, which showed a 21% increase compared to the absence of nitrogen. The results of mean comparison showed that in conventional tillage treatment contents of chlorophyll a, b and total showed 8.4%, 23.7% and 12.6% increase compared to intensive tillage, respectively. Comparison mean of nitrogen treatment showed that contents of chlorophyll a, b and total at 150 kg ha-1 of nitrogen fertilizer were 10.92, 3.59 and 14.51 mg g-1 fresh weight, respectively. Consumption of 200 kg ha-1 of nitrogen fertilizer included the highest nitrogen contents of dry matter (1.27%). The results also showed that the highest nitrogen contents of dry matter was assigned to the second year and conservation tillage by 1.25% and the lowest was obtained in the first year and conventional tillage (1.1%). These parameters can be augmented the N and other elements absorption. Moreover, decomposition of organic matters is accelerating in conventional tillage because of more incorporation of residues with the soil. As a result of this process, more nutrient elements were probably absorbed by the roots and enhanced the grain yield, consequently.

According to the results of conservation tillage, it had a more beneficial effect on increasing growth characteristics, yield, yield components and nutrients than conventional and intensive tillage system. It can be stated that the implementation of conservation tillage is able to help absorb nitrogen, which improves yield.

Drought stress can have many effects on the agronomic and physiological characteristics of plants. Corn is used in human and animal nutrition. It has 60-72% starch and 8-11% protein (Darrah et al., 2019). The high water requirement of corn is one of the most important effective factors in preventing the development of its cultivated area. Therefore, It is very important to introduce new corn hybrids that tolerate drought (Corcoles et al., 2019: Rudnick et al., 2017). Selenium is an essential and rare element, which has many effects on human health and physiological characteristics of plants (Rayman, 2017). The research results have shown that the use of selenium fertilizers is a suitable solution to increase the tolerance of plants to environmental stresses such as drought stress. This research was conducted to investigate the effect of selenium spraying on the electrical conductivity of cell sap in corn cultivars under drought stress conditions.

This experiment was conducted in 2011 in the twice split-plot arrangement of treatment in a randomized complete block design with three replications in a training-research farm. Payam Noor University of Central Province (Arak city) was implemented. Drought stress (I0= Control irrigation, I1= Irrigation about 80% plant requirement water, I2= Irrigation about 60% of plant requirement water, were assigned in the main plots, maize cultivars (V1= KSC 500, V2= KSC 520, V3= KSC 700) in sub plots and foliar treatment of selenium in two levels (Se0= Control, Se1= 20 g ha-1) in sub-sub plots. In this study characteristics such as: ear height, panicule length, number of ear m-2, stem height, forage yield and un-stability of cell membrane were assessed.

The results showed that the effect of water stress treatment on the traits of stem height (5%), forage yield and cell membrane instability (1%) was significant. Also, the difference of maize cultivars was significant in terms of the number of ear m-2, forage yield and cell membrane instability. The highest and lowest values of cell membrane instability with an average of 1759 and 1456 µs cm-1, respectively, belonged to the irrigation treatment based on 60% of the water requirement of the plant and the control irrigation treatment. Among the maize cultivars, the highest and lowest values of cell membrane instability with an average of 1675 and 1587 µs cm-1, belonged to KSC 700 and KSC 500, respectively. Selenium consumption had a positive effect on reducing the amount of cell membrane instability, so that the average cell membrane instability in the treatment without selenium consumption decreased from 1687 to 1601 µs cm-1, in the treatment with selenium consumption.

The results of this research showed that by changing the irrigation regime from normal conditions to irrigation based on 60% of water requirement of maize, forage yield decreased by 23.35%. The response of maize cultivars was also different in terms of forage yield, so that cultivar KSC 700 was superior to the other two cultivars. The use of 20 (g ha-1 of selenium) increased the forage yield by 64.4%.