وحید رهجو

 Powdery mildew of sainfoin (Onobrychis viciaefolia Scop) is one of the most important diseases of this crop, which primarily spreads in the last cuts and causes loss. If this disease spreads widely on plants, it will cause the loss of leaves and, as a result, reduce the crop's forage yield. On the other hand, because there is little research in this field in the country, it was necessary to conduct research to identify the superior populations that are tolerant to the disease and have desirable agronomic traits, which was the goal of this study.

For investigating the reaction of different populations of sainfoin (Onobrychis viciaefolia) to powdery mildew, an experiment was conducted using a randomized complete block design in three replications in Karaj, Iran, with ten treatments including two improved populations and eight ecotypes of cultivated sainfoin collected from its habitat and identified from different regions of the country. Evaluation of powdery mildew disease was done in natural conditions in the last cut of plants in the summer of 2021. Disease evaluation of treatments in the field was done by recording traits such as disease incidence and severity. Also, a greenhouse experiment was conducted on the same populations using a completely randomized design with four replications of the treatments, and at least five plants were considered for each ecotype in each replication. The inoculum was prepared by creating a spore suspension with a concentration of 106 spores per ml and sprayed on sainfoin seedlings of different ecotypes at the four to five-week stage that had eight to ten leaves in a greenhouse with a temperature of 23 to 29°C and relative humidity of about 75%. The reaction of ecotypes to the disease was evaluated two weeks after inoculation, and the infection percentage of each population was recorded. The evaluation in the greenhouse and the scoring scale similar to the field evaluation was conducted following a scoring scale of one to four based on the treatments' disease severity percentage. Also, the dry matter (DM) yield of populations for four cuts was calculated. 

Based on the variance analysis data of the field trial in Karaj over two years, it was concluded that there was a significant difference for both disease severity and disease incidence at α=1% level. Also, there was a significant difference in disease severity and incidence at α=1% level among all populations in greenhouse trials. The results related to the disease incidence of the populations in both years showed that in the field trials among all the populations in the first and second years of the research, population number 2 had the minor disease incidence in the field, with values of 33 and 30 percentages, respectively. In the greenhouse test, the same population with values of 47 and 60 percent, respectively, had the lowest DI rate among the populations. Also, the results related to the disease severity (DS) of the populations in two years showed that population number 2 was known to be the most tolerant to the disease, with values of 18 and 10 percent in the first and second years, respectively, and other populations were considered as susceptible to the disease. In greenhouse trials, population number 2 was recognized as the most tolerant population, with 23% and 22% disease severity in the first and second years, respectively, and other populations showed a semi-susceptible to susceptible reaction to the disease.

In total, by comparing the average data in field and greenhouse tests over two years, it was concluded that population number 2, with an average disease severity of 14% and an average dry matter yield of 14.68 tons per hectare, was known as a disease-tolerant population coupled with desirable dry matter yield. Although this population was not completely resistant to powdery mildew, it was introduced as a semi-resistant variety (MR) to the disease, as its disease severity was less than 25% in all experiments.

Fusarium verticillioides (Sacc.) Nirenberg causes maize ear rot in all maize-growing regions of the world and produces mycotoxins that contaminate maize grains. Therefore, it is considered an important species in terms of food health for both animal and human in the world. One of the best approaches to address this disease is to identify highly tolerant or resistant genotypes that can be used for genetic improvement. In this experiment, the resistance of 16 late maize hybrids was evaluated for cob resistance, silk channel resistance, and resistance in the germination stage using three inoculation methods. The objective of the current study was to select the genotype with high resistance in all three developmental stages.

The seeds of 16 late maize hybrids were obtained from the Maize and Forage Crops Research Depatment (MFCRD), Seed and Plant Improvement Institute (SPII), Karaj, Iran, and were planted in a randomized complete block design with three replications in the research field of MFCDR, in 2021. To inoculate the plants, the Kj7 isolate collected from infected maize cobs in the field of MFCDR was used. Maize hybrids were screened with three methods. In the first method, the resistance of the studied hybrids was evaluated by the rolled paper method at the germination stage. In the second method, the cob resistance was assesed by creating a wound in the middle of the cob and injecting spore suspension, and in the third method, silk channel resistance was investigated by injecting spore suspension into the silk channel seven days after the appearance of silks. Data statistical analysis was done by analysis of variance and comparison of means with Duncan's test using SAS software.

The results of analysis of variance and comparison of means showed that there was a significant difference among the studied 16 maize hybrids in terms of disease resistance with all three methods of artificial contamination. According to disease severity measurement in all three evaluated methods, the hybrids H3, H8, H11, H12 and H13 were selected as hybrids with high resistance against pathogenic fungi. These hybrids showed suitable resistance against all main methods of fungal infection and were superior hybrids compared to the other hybrids evaluated in this study in terms of resistance to maize ear rot caused by F. verticillioides. The implementation of these screening assays in maize breeding programs can be effective for classifying the degree of flexibility of maize germplasms to fusarium head rot.

The results of this experiment indicated that to evaluate the fusarium ear rot resistance of maize genotypes, the cob resistance method can be used as the main evaluation method especially in dry regions. Silk channel resistance can be used as a control method to evaluate the possible sensitivity of resistant or semi-resistant genotypes in humid areas where contamination with this method is important. Also, due to the different reaction of a number of hybrids investigated at the germination stage in this study and the possibility of the fungus growing as an endophyte in the plant, it is recommended to evaluate the new cultivars being introduced at this growth stage. Finally, hybrids should be introduced as resistant to this disease, which have shown a suitable reaction to the fungus in all three methods.

Fusarium verticillioides is a fungal pathogen of maize that causes ear rot and contaminates the kernels with fomunisin mycotoxin. Induced resistance to diseases is one of the ways which plants use against pathogens. This research was conducted as a randomized complete block design with three replications for six different time courses (0, 24. 48. 72. 96 and 120 hours post inoculation) and with two resistant (K18) and susceptible (MO17) maize lines in the greenhouse of Seed and Plant Improvement Institute (SPII), located in Karaj. In order to better understand the defense systems of maize at the molecular level, plants were inoculated with a spore suspension of F. verticillioides at a concentration of 106 by creating a wound in the middle of the ear, one week after silk emergence. The expression rate of ZmCCoAOMT2 and CYP450 89A genes was checked using the Real-Time PCR evaluation method. The results showed that the expression level of both genes increased in the resistant line. The ZmCCoAOMT2 and CYP450 89A genes reached their maximum expression level 48 and 96 hours after inoculation respectively, in the resistant cultivar. A decrease in the expression level of ZmCCoAOMT2 gene was observed in the susceptible line after fungal inoculation, but the expression of CYP450 89A gene increased in this line. In general, the results of this research showed that the studied genes are related to the interaction of the plant with the pathogen and may help to induce resistance in the plant.

IntroductionTarget leaf spot of sorghum, caused by fungal species Bipolaris sorghicola, is considered as one of the most important leaf diseases in sorghum, so that occurrence before flowering, can lead to damage and reduction of more than 50% of grain yield. This disease is also significant in Iran and usually occurs in most of the humid regions of the country, where sorghum is cultivated. Since there are very few researches on leaf spot diseases in sorghum especially on the resistance of sorghum cultivars in the country, it seems necessary to carry out research in this field. Therefore, the present research was carried out with the aim of evaluating the response of different sorghum genotypes to leaf spot disease. The resistant genotypes identified in this research can be used to transfer favorable characteristics to the host plant in future breeding programs.Materials and methodsTo study the reaction of different forage sorghum genotypes to target leaf spot, 25 sorghum genotypes, including ten commercial hybrids and 15 promising lines were evaluated in a randomized complete block design with three replications in two regions, Karaj and Gorgan. Artificial inoculation of genotypes in the field was carried out with a mixture of several pathogenic isolates of the disease-causing fungus in two stages. The first, at the 3-4 leaf stage by injection of spore suspension (3 ml per each whorl) using a syringe stage, and the second, at the 6-8 leaf stage using the Bazooka method by placing 2-3 fungus infested sorghum grains in the whorl of each plant. To evaluate the reaction of genotypes and progress of the disease, characteristics such as percentage of disease incidence (DI%) and disease severity on each plant (DS%) were recorded two weeks after the last inoculation. In addition to the field experiment, the reaction of the genotypes to the disease was investigated in a greenhouse experiment based on a completely randomized design with three replications.Research findingsThe results of this experiment showed that there was a significant difference between the studied sorghum genotypes in terms of resistance or susceptibility to leaf spot. Comparison of genotypes showed that the disease severity of the studied lines and hybrids varied from 0.7% to 51.7% in the Karaj region, and from 1.7% to 66.3% in the Gorgan region. Hybrid No. 8 (FGCS110) with 0.7% and 1.7% disease severity in the Karaj and Gorgan regions, respectively, had the lowest disease severity and was recognized as the most resistant genotype in both regions. In contrast, line No. 2 (FGS109) with disease severity of 51.7% and 66.3% in Karaj and Gorgan regions, respectively, was the most susceptible genotype. Furthermore, a statistically significant difference was observed among the studied regions for disease severity of all genotypes, so that the recorded disease severity in Gorgan was higher than in Karaj. Also, there was a positive and significant correlation (r = +0.74, p< 0.01) between disease severity (DS%) and disease incidence (DI%) measured in different sorghum genotypes in two studied locations. The results of greenhouse experiment also confirmed the results of field experiment.ConclusionThe results of the current research led to the identification of resistant and semi-resistant sorghum genotypes to leaf spot among the studied genetic materials, which can be used in future breeding programs. The results obtained from the Karaj region showed that genotype No. 8 (foreign hybrid FGCS110) was highly resistant, line No. 13 and foreign hybrids No. 1, 6, 7, and 10 were resistant, and the number of 11 lines along with a foreign hybrid were semi-resistant. In the Gorgan region, foreign hybrids No. 7, 8, and 10 were resistant, and seven lines and five foreign hybrids also had a semi-resistant reaction to the disease, while no resistance reaction was observed in any of the studied lines in this region.

The present study is conducted to separate the effective and influential management factors in the production of clover forage in Iran and to identify its limiting factors. In this study, the data obtained from 68 research projects conducted by the Agricultural Research, Education, and Extension Organization (AREEO) throughout the country during the 2009-2020 years have been analyzed, using the meta-analysis method. The results show that planting date -3.31%, planting method -22.82%, species +40.14%, seeding rate (planting density) +1.53%, drought stress -16.16 %, and phenological stage of forage harvesting -15.42% justify the amount of forage clover variation. Thus, fall planting in the middle of September, basin planting method, choosing the Berseem clover species (Trifolium alexandrinum var. Karaj), the seeding rate of 15-20 kg ha-1 (for forage production), and forage harvesting at the phenological stage of 10-25% flowering, are the most important management and agronomic factors in increasing clover forage production in cold and temperate regions, and not complying with one or a set of these factors will reduce the clover production and will cause yield gap. Overall, the species, planting method, and drought stress are respectively recognized as the most important factors affecting clover forage yield in Iran.

Climate change drastically reduces the amount of water available to plants and increases the severity and frequency of droughts. By the end of this century, it is anticipated that droughts will continue to increase significantly. Drought stress, as one of the major climate events, induces physiological and morphological alterations, which can restrict crop growth, yield, and quality. In recent years, separate research projects and studies in the country have evaluated the effects of drought stress on grain maize, forage maize, grain sorghum, forage sorghum, grain millet, alfalfa, and clover yields, as well as the effects of drought stress on their yield gap. However, if the results of these separate studies were evaluated together, it would have been possible to compare the drought sensitivity and tolerance of various crops. Consequently, the optimal crop to plant under drought-stress conditions in the nation's agroecosystems would be determined. The meta-analysis is a statistical analysis that can assess the aggregate effects of numerous studies conducted under varying conditions. In other words, meta-analysis is a statistical technique for integrating the findings of multiple studies in order to comprehend a problem. The purpose of this meta-analysis was to determine the impact of different drought stress levels on the yields of grain maize, forage maize, grain sorghum, forage sorghum, grain millet, alfalfa, and clover.

In this study, the data obtained from 145 final reports of the Agricultural Research, Education, and Extension Organization (AREEO) and published articles over the past decade were analyzed using the meta-analysis method. This included grain sorghum (18 studies), forage sorghum (21 studies), grain maize (28 studies), forage maize (23 studies), grain millet (18 studies), alfalfa (17 studies), and clover (20 studies). In addition to the difference in quantitative results between studies, the effect size variance was utilized in this method. Consequently, the means, standard deviations, and sample sizes (replications in each study) for the control and evaluated treatments were determined. After classifying the data, the reaction ratio (R) and its natural logarithm were calculated. Subsequently, the method determined which treatments have additive or decreasing effects on yield under drought stress conditions, as well as which treatments had no positive or negative impact on yield. Utilizing the T-test, a group comparison was conducted between the mean yield under drought stress conditions and the mean yield under normal irrigation conditions in order to determine the significance level of yield changes caused by drought stress. The statistical analysis and preparation of the figures were performed by Excel.

According to the findings of the meta-analysis, the overall effect of drought stress on the yield of all seven crops was significant for grain sorghum (-16.30%) (P<0.05), forage sorghum (-18.27%) (P<0.05), grain maize (-31.75%) (P<0.01), forage maize (-33.24%) (P<0.01), grain millet (-25.66%) (P<0.01), alfalfa (-30.79%) (P<0.01), and clover (-32.14%) (P<0.01). The yield reductions in grain maize, forage maize, alfalfa, and clover were significant under all levels of drought stress, whereas grain sorghum, forage sorghum, and grain millet yield reductions were significant only under severe drought stress. The yields of grain sorghum, forage sorghum, grain maize, forage maize, grain millet, alfalfa, and clover decreased by 10.03, 11.84, 18.21, 20.27, 14.13, 19.74, and 20.37%, respectively, under moderate drought stress, and 21.98, 25.41, 39.09, 41.37, 32.55, 40.13, and 42.08%, respectively, under severe drought stress.

As a result, it is impossible to cultivate and develop grain maize, forage maize, alfalfa, and clover in areas with limited water resources without significantly reducing yield. According to the findings of this meta-analysis, grain sorghum, forage sorghum, and grain millet with a moderate drought stress tolerance threshold could be recommended for cultivation in regions where drought stress conditions are likely to occur.

Timely planting of sorghum, taking into account the climatic conditions of the region, especially sufficient water supply, can improve the growth period of this plant in the region. In this regard, In order to determine of economic productivity of irrigation water in the production of forage sorghum cultivars by using of different planting methods in different dates, an experiment was carried out as a split factorial based on randomized complete block design with three replications at the Seed and Plant Improvement Institute in Karaj, Alborz province, Iran during 2017 and 2018. In this research, The main factor was the planting date at four levels (1, 11, and 23 July and 1 August) and the sub-factor included planting methods (direct seeding without pre-treatment, hydroprimed seed planting, and transplanting) and forage sorghum cultivars (Pegah and Speedfeed). In order to measuring of productivity be used indicators of physical productivity (kg m-3) and economic productivity (rials gross and net income of products m-3) and estimating of return be used profitability indexes (gross income and net income). According to the results, the planting of speedfeed sorghum cultivar to hydroprimed seed planting with irrigation water consumption (4790.5 m3 ha-1) , economical productivity od water (20687.5 rials net income m-3) and maximum net income of forage production (99.11 Iranian million rials ha-1) in date of July 1st recommended as suitable treatment based on return and economical productivity of water in the target area.

To evaluate the effect of seed pre-soaking on forage yield and quality and water productivity in late planting of two forage sorghum cultivars, a field experiment was conducted was conducted as split factorial arrangements in randomized complete block design with three replications in 2017 and 2018 growing seasons at the research field of Seed and Plant Improvement Institute, Karaj, Iran. Four planting dates; July 1st, July 10th, July 23rd, and August 1st were assigned to the main plots, and factorial arrangement of seed treatments (without pre-soaking as control and seed pre-soaking) and sorghum cultivars (Peghah and Speedfeed) were randomized in sub-plots. The results showed that days from planting to the emergence of sorghum cultivars were reduced by four to six days, at different sowing dates, as affected by seed pre-soaking treatment. Late planting significantly reduced forage production, dry matter yield, protein yield, and digestible dry matter yield but improved crude protein content and dry matter digestibility. The highest fresh and dry forage yields (147.79 and 32.82 ton ha-1, respectively) and the maximum digestible dry matter and protein yield (18498 and 2904 kg.ha-1, respectively) were obtained in seed pre-soaking treatment of cv. Speedfeed in July 1st planting date. The highest water productivity for dry matter production (7.22 kg.m-3) was recorded in seed pre-soaking treatment of cv. Speedfeed in July 23rd planting date. Although seed pre-soaking reduced the digestibility of dry matter by 0.64% compared to without pre-soaking treatment, but significantly increased digestible dry matter yield and protein content. Peghah cultivar was superior for crude protein content and dry matter digestibility, and cv. Speedfeed for forage yield and water productivity. Based on the results of this experiment, seed pre-soaking treatment could compensate for the delay planting of two forage sorghum cultivars by increasing forage yield. The results of this experiment also showed that seed pre-soaking and July 1st planting date were more effective on the performance of cv. Speedfeed.

To identify the limiting factors in forage maize production in Iran, this study has been carried out in order to separate the effective and influential management factors in forage maize production in the country with data. It is obtained from 43 final reports or their derived extracted articles in Agricultural Research, Education and Extension Organization (AREEO) with meta-analysis method. According to the results, plant density (5.65%), drought stress (-13.44%), cultivar (0.31%), planting date (2.54%), and nitrogen fertilizer (24%) justify the amount of forage maize variation. Based on the results of this study, forage yield has increased by about 9.49%, increasing plant density between 80 to 100 thousand plants per hectare. Maize forage yield has decreased significantly under mild stress, severe stress, and very severe drought stress by 25.30%, 14.38% and 8.99%, respectively. Also, for different cultivars and different groups of maturity, group-700 has had a significant increase of 3.83% compared to other groups. For the planting dates of forage maize compared to the control, which is the first half of June, a decrease in forage yield is observed. Finally, the highest percentage of increase in maize forage yield has been obtained from the use of 450 kg ha-1 of urea fertilizer. Overall, nitrogen fertilizer, drought stress, and planting density are recognized as the most important factors affecting corn forage yield in Iran, respectively.

To evaluate the effect of planting management on forage production in hybrid and open-pollinated sorghum cultivars, a two-year experiment based on split plot factorial in randomized complete block design with three replications was conducted at the Seed and Plant Improvement Institute, Karaj, Iran. Planting date at four levels (July 1, 10 and 23, and August 1), was considered as the main factor and the factorial combination of planting method at three levels (without priming as control, seed hydropriming, and transplanting) and genotype at two levels (Pegah cultivar and Speedfeed hybrid) as the sub-factor. The results showed that delayed planting on July 10th and 23rd, and August 1st reduced forage yield by 15.1, 32.7, and 48.7%, respectively, compared to the July 1st planting date. The highest silage yield in the first and second harvests (106.21 and 62.78 ton.ha-1, respectively) were obtained by the transplanting Pegah and Speedfeed on the July 1st, respectively, whereas the seed hydropriming of Speedfeed produced the highest total forage yield (147.80 ton ha-1). The results of the economic evaluation showed that the highest net income (99.11 million Rials.ha-1) and the maximum benefit-to-cost ratio and sales return (2.52 and 60.35%, respectively) were obtained by planting the hydroprimed seeds of Speedfeed hybrid on the July 1st. The transplanting of Pegah cultivar was uneconomical in all the studied planting dates, whereas transplanting Speedfeed hybrid from July 1st to July 23rd was superior to the conventional sowing method. In total, the results of this study showed that to produce the maximum yield and economic profit, it is recommended to carry out the planting operation at the earliest possible time with hydroprimed seeds of Speedfeed hybrid.

To identify the limiting factors in grain maize production in Iran, a study has been carried out to particulate effective and influential management factors of this crop’s production in the country. The data come from 95 final reports or extracted articles in Agricultural Research, Education, and Extension Organization (AREEO), undergoing meta-analysis. Based on this study, of all grain maize variation, 2.93% is justified by plant density, 6.81% by planting structure, 11.12% by planting rotation, 2.28% by conservation agriculture, 25.28% by drought stress, 4.99% by cultivar, 4.46% by planting date, and 25.84% by nitrogen fertilizer. Accordingly, 100 thousand plants per hectare, zigzag double rows planting structure, maize-leguminous crops planting pattern, cultivating in residue, optimum irrigation without drought stress (in case of water availability), 700 maturity group cultivar (in case of adequate growing season), planting in May and early August in temperate and tropical climate, and using maximum 100-300 kg urea fertilizer per hectare are recommended to decrease yield gap in grain maize production.

In order to study the Bipolaris and Curvularia species associated with corn, sorghum and sugarcane, sampeling were performed from different regions of Iran (including Alborz, Ardabil, Fars, Gilan, Golestan, Khuzestan, Mazandaran and Zanjan provinces) during the summer of 2011 and 2012. Fungal species were identified based on morphological features and molecular data of ITS regions of ribosomal DNA. Eleven species including Viz. Bipolaris cynodontis (48 isolates), B. sorghicola (16 isolates), B. maydis (17 isolates), B. sorokiniana (seven isolates), B. bicolor (four isolates) and B. oryzae (two isolates), Curvularia spicifera (19 isolates), C. papendorfii (ten isolates), C. ellisii (two isolates), and C. hawaiiensis (one isolate) were identified. Pathogenicity test of the species were performed on four to six leaf stage of corn, sorghum and sugarcane seedlings. Finally, pathogenicity of B. maydis, B. sorokiniana and B. oryzae on corn and B. sorghicola on sorghum seedlings were confirmed. This is the first report of occurrence and pathogenicity of B. sorokiniana and B. oryzae on corn leaves in Iran.

The Persian clover is one of the native forage crops in Iran for which no bred cultivar has been released yet. For identification and release of the first Persian clover cultivar a series of experiments were conducted from 2000 to 2016 cropping seasons. At first, 14 Persian landraces were collected from regions with known clover cultivation in the country and then individual plants were selected from each population in 1999-2000 cropping season. In total, 176 single plants with superior forage performance were selected in this stage. In 2004-2005 cropping season, seeds from single plants were sown in rows and were compared with Haftchin local Persian clover as check. The preliminary and semifinal forage yield comparisons were conducted to evaluate dry and fresh forage yields of superior clover lines in 2006-2009 cropping season. The VCU test (Value for Cultivation and Use) of the 14 selected lines along with a local Persian clover (Haftchin) as a check was carried out in the uniform regional trials in Kermanshah, Karaj and Borujerd Research Stations. In this experiment BPC/Borujerd/81.13 line (Attar) had 2061 kgha-1 higher yield for dry matter compared to the control. Also, to evaluate response of different Persian clover germplasm to rust disease, two experiments were conducted in Borujderd and Karaj regions. The results showed that all lines as well as control (Haftchin) were relatively sensitive to the rust disease. These lines were compared with the control cultivar (Haftchin) under on-farm conditions in Borujedrd and Aleshtar regions, as the main centers of clover cultivation, in 2015-16 cropping season. The results showed that Attar with 72.99 and 11.08 tha-1 fresh and dry forage yields, respectively, showed 23.65 and 21.79% yield superiority to the control cultivar.  Furthermore, this new cultivar showed more yield stability and forage yield compared to the local cultivar. Hence, it was released with the name of "Attar" as the first Persian clover cultivar.

In order to stablity analysis of foxtail millet, six foxtail millet genotypes (five new genotyps and Bastan as control) were cultivated in six locations (Karaj, Gonbad, Varamin, Yazd, Sari and Birjand) across two years in a randomized complete block design with four replications. the results of combined analysis for studied traits (number of tillers, number of leaves, days to flowering, height, fresh forage yield, dry forage yield and seed yield) showed that the cultivars and environments main effects and intraction between cultivars and environments were statistically significant. all of the studied genotypes except G4 had forage yield higher than Bastan (control). the total mean (fresh forage yield) was 24.76 t/ha and the average of all cultivars except G3 and G5 was lower than total mean. the results of the stability analysis by differnrt methods showed that G5 was high yield and stable genotype in the studied environments. spearman's rank correlation between forage yield and stabilty parameters showed strong negative correlation between forage yield and superiority index (Pi) and ranking (Si). these results indicated thet use of Pi and S1 for simultanious selection of stable and high yielding foxtail millet genotypes would be efficent. reggersion deviation, Wricke oekovalenz and Shukla stability variance are equivalent in ranking genotypes for stability and could be substituted with each other in breeding programs. in conclusion, the results showed that G5 had high yield and good stability to all environments and could be introduced as a new cultivar.

Grain mold caused by Fusarium verticillioides is one of the most dangerous food and feed safety challenges in sorghum production. The most efficient solution for reducing the hazards of the disease is breeding resistant varieties. In order to find the resistant sorghum varieties, nine sorghum varieties were evaluated for their reaction to F. verticillioides and fumonisin accumulation in their kernels under field conditions in Ardabil Agricultural Research Station, Moghan region, Iran (39° 41' N 47° 32' E, with 40-50 m above sea level), using a randomized complete block design with three replications. For artificial inoculation, sorghum panicles were sprayed with the mixture of spore suspension at 50% flowering stage. Two months after inoculation, disease severity was evaluated based on disease progress in each panicle. In addition, total fumonisin produced on sorghum kernels was measured using ELISA kits. The results showed that among studied varieties, KGS12 and KGS15 were moderately resistant and the other eight varieties were highly susceptible or susceptible to grain mold. The mean grain yield under artificial infection showed a reduction of 46.2% in comparison to the natural infection condition (control). The fumonisin accumulation in grains varied from 0.35 ppm (in KGS11 variety) to 1.83 ppm (in Sepideh variety) at the artificial infection condition, while the range was from 0 ppm (in the Kimia variety) to 0.16 (in the KGS15 variety) at the natural infection condition. The mean fumonisin accumulation under natural and artificial infection conditions was 0.07 and 1.00 ppm, respectively, which showed an increase of 1328% in comparison to the control treatment. In general, KGS12 and KGS15 were identified as superior varieties due to their lower disease severity and fumonisin accumulation and acceptable grain yield as compared with other varieties.

Common smut is an important disease of maize that occurres in many maize growing countries as well as in Iran and causes considerable damages on yield. Damage of the disease varies by race of the pathogen, susceptibility of host, agronomic procedures and nitrogen fertilizers application on crop. Damages up to 50% on susceptible cultivars have been reported frequently. Control of the disease through common methods is difficult and use of resistant cultivars is the best method for control of the disease. In the present study response of 29 maize genotypes including 16 hybrids and 13 parents to prevalent races of the pathogen was evaluated in field condition in Karaj and Isfahan in 2014. All ears of plants in each plot were inoculated with a suspension of sporidia of five isolates of the pathogen and disease severity was scored at the end of the season and respose of genotypes was evaluated. Based on the results, only line S61 was resistant and the remaining were moderately resistant except OH43/1-42 and KE 78008/212 which were highly susceptible. Among hybrids, KSC 201 (K1263/17 × S61) was highly resistant, KSC 400 (KE 72012/12 × KE 1263/1), KE 75016.321 × K 1264/5-1 and KSC 260 (K 615/1 × K 1264/5-1) were resistant and the remaining hybrids were moderately resistant or moderately susseptible.

The contamination of canola seeds to various fungal agents is important like other crops and it is varied annually. Diseases like blackleg and sclerotinia stem rot are considered as the most important diseases in Iran. The possibility of their direct spread through seed contaminations and indirect spread through infected debris in seed masses will have danger of their development. For investigating canola seed contamination to fungal agents, seed samples were collected from seed parties of canola grown in cold areas including Alborz, Kermanshah and Markazi provinces. The surface of seeds were observed to differentiate and separate different abnormal appearances including wrinkle, presence of cracks, oozes, hyphal shape particles, and black spots. The presence of sclerotia of stem rots disease causal agent, and plant debris containing pycnidia of blackleg disease were checked in seed samples using stereo microscope. The identification of fungi on the seeds was done with and without surface disinfection processes. The plant debris in non-sieved seed samples did not have structures similar to pycnidia of blackleg disease. The results obtained demonstrated that the seed samples were contaminated to fungi including  Penicillium sp.,  Alternaria sp.,  Aspergillus sp., and  Rhizopus sp..

Diseases of canola including stem white rot caused by Sclerotinia sclerotiorum and blackleg caused by Phoma lingam are considered as the most important diseases in Iran. Seed infections have their own importance and vary annually under different conditions. For this investigation، 26 canola fields located in three areas of Eastern (Kalaleh)، Central (Ali Abad)، and Western (Kord-Kouy) regions of Golestan Province were selected to study both diseases. At the cropping season، seed samples of every 10 plants demonstrating the diseases were collected separately and transferred to plant pathology laboratory. Seed weight and seed germination factors were measured for each samples even on non-infected samples. The colonies grown were studied employing fungal identification keys. The seed weight of samples infected to blackleg did not show considerable difference with the control samples whereas sclerotinia had decreased this factor totally. There were not sensible differences between treatments for seed germination. Fungi including Alternaria، Penicillium، Aspergillus، Rhizopus، and Sclerotinia were identified on seed samples in this experiments. The seeds of blackleg infected plants did not result in seed contamination and only one sample of Sclerotinia affected plants demonstrated the fungal colonies of the pathogen.

Southern corn leaf blight caused by Bipolaris  maydis is one of the most important diseases of maize and causes major losses in quality and quantity of yield in corn. The most effective way for control of disease is use of resistant cultivars. To evaluate the reaction of maize genotypes to the disease on experiment was arranged as split plot in RCBD with three replications and 15 genotypes (6 hybrids, 9 lines and a susceptible check) at Karaj and Sari stations. The mixture of five aggressive isolates were used for artificial inoculation at two growth stages of plant (spraying with spore suspension at 4-6 leaf stage and Bazooka technique with sorghum kernels infected to B. maydis at 6-8 leaf stage). Genotypes were evaluated based on disease severity percentage on leaves two weeks after flowering time. The results of combined variance analysis showed that there was a significant difference at 1% probability level among corn genotypes. Based on the results, three lines K1263/17, K615/1, S61 and two hybrids KSC 201 and KSC 301were susceptible, four lines K1263/1, KE75039, K1264/5-1, K1728/8 and hybrid KSC 260 were moderately susceptible, two lines OH43/1-43, KE72012/12 and two hybrids KSC 250 and KSC 340 were moderately resistant. Hybrid KSC 400 was the only genotype that induced chlorotic lesion on lower leaves of all genotypes and was assessed as resistant. Due to favorable climatic conditions and high disease incidence in Sari station percentage of susceptible genotypes in Sari (53.33%) was higher than that Karaj (26.69%).

Fusarium ear rot is the most important disease of corn in Iran. In this research with the purpose of studying the casual agent, some infected ears of corn were collected from fields of Esfahan, Sari, Kermanshah and Karaj. A total of 40 Fusarium isolates were identified after isolation and purification. According to valid mycological key references based on the different morphological characters and some physiological traits, 32 Fusarium verticillioides and 8 Fusarium proliferatum isolates were identified. In order to evaluate the pathogenicity variation of 22 Fusarium verticillioides isolates on susceptible maize line (MO17), the causal agents of Fusarium ear rot of corn, an experiment based on a randomized complete block design (RCBD) with 24 treatments (The treatment were consisted of 22 F. verticillioides isolates, one control with sterile distilled water inoculation, and one control without inoculation) and three replications were conducted in greenhouse and field. The results of the analysis of variance of data showed that difference between treatments were statistically significant. Totally, three isolates (4 and 6 from Karaj, 20 from Sari) of Fusarium verticillioides showed the highest level of virulence among all 22 isolates in greenhouse. Totally, two isolates (14, 18 from Sari) of Fusarium verticillioides showed the highest level of virulence among all 22 isolates in field.

In order to study and identify the sorghum seed borne fungi، sampling was done from different sorghum fields of Karaj، Gorgan، Sari، Amol، Moghan and Zabol during 2010 and 2011. The leaves of sorghum showing leaf spot symptoms were also collected to detect the causal agents of disease. Standard methods including culture on different agar media، blotter test and seed washing method were used to determine the seed health and isolate fungal strains. Fungal isolates were purified using single spore or hyphal tip transfer techniques and identified using valid mycological keys. In this survey totally 19 genera and 18 different fungal species were isolated، purified and identified. Fungi most frequently isolated and identified from different sorghum panicles were Fusarium verticillioides، F. peroliferatum، Aspergillus sp.، Curvularia sp.، and Alternaria sp. The other fungi with less frequency were also isolated from sorghum seeds. Also 7 Fusarium spp.، 10 Alternaria spp.، 4 Curvularia spp. and 4 Bipolaris spp. isolates were isolated from sorghum leaf pieces showing leaf spot symptoms after culturing on different agar plates.

Fusarium proliferatum is the dominant agent of maize fusarium ear rot in many areas of the world especially in Iran. Among several Fusarium isolates recovered from infected maize ears, 12 isolates were identified as F. proliferatum according to morphological and physiological characteristics. In order to determine mating population and mating type of isolates, all 12 isolates were crossed with standard tester isolates of F. proliferatum on Carrot Agar (CA) media and were incubated under the mixture of cool-white and near-UV lights for three to four weeks. This test was repeated twice with three replications. Morphological identification of all isolates was confirmed by mating population test so that all 12 isolates of F. proliferatum belonged to mating population D of Gibberella fujikuroi complex. The results of mating type test showed that seven isolates were MAT-1 (58.3% frequency) and five isolates were MAT-2 (47.7% frequency). Pathogenicity test on stems of susceptible maize line (MO17) was done using toothpicks method in field, greenhouse and laboratory (Detached stem). The Pathogenicity of isolates was evaluated by measuring the necrosis length on inoculated stem. The results of variance analysis of pathogenicity tests showed significant differences among isolates in all mentioned methods. In field, greenhouse and laboratory trials, isolates SK27, SK32 and SK24 had the highest diseases severity (length necrosis), respectively. Significant and positive correlations were observed between field and greenhouse tests (r = 0.86**), field and  laboratory tests (r = 0.75**), and greenhouse and laboratory tests (r = 0.75**).

Alfalfa downy mildew, caused by Peronospora trifoliorum, is one of the limiting factors in alfalfa production. Under favorite conditions in spring, the disease is prevalent after first moving and the plant leaves turn to yellow followed by drying. The standard greenhouse experiments and field screening methods are applicable to select the resistant ecotypes of alfalfa to this disease. In greenhouse tests, seven days old seedlings of alfalfa are inoculated with spore suspension. After completion of incubation period and the first symptoms were observed, the percentage of the symptomless seedlings are comparing with resistant control. Field experiments must be carried out for different alfalfa ecotypes in locations with suitable conditions for natural occurrence of disease, using an appropriate statistical design with minimum three replications. The response of cultivars evaluate based on disease severity. In Iran, the cultivars KS224 and Saranac showed resistance to downy mildew and some ecotypes like Kiseverdai, Nikshahri, Gharghlooogh, Malek-Kandi and Gharghloogh known as tolerant to disease.