In order to study the effect of sowing date and plant density on ear of sweet corn an experiment was conducted in Gorgan Reaserch station since June 2001 during 3 years. In this experiment five sowing date (24th June, 9th July, 24th July, 18th Agust and 23th Agust) and four plant density (45000, 55000, 65000 and 75000 plant per hectar) were evaluated in form of factorial experiment (5×4) within randomized comelet block design. Results indicated that ear length, plant hight, can seed weight, grain/ear ratio and harvest index was under the influence of year and maximum ear weight obtained amount 12810 kg/ha in theirty year. With delay sowing date until 9th July amount of ear weight was fixed but amount of it in July was smaller than June. Although with delay sowing date in July ear weight was fixed and maximum ear weight achived amount 13690kg/ha in 24th June. Stistically there wasn’t any different between plant density for ear weight and can seed weight but with increase plant density ear length and grain/ear ratio decreased. So for obtain maximum yield and marketable 45000-55000 plant/ha for sweet corn in Summer sowing can be recommended.

Saffron is one of the most important horticultural crops in Gonabad, Iran. There are many families that earn their livelihood with Saffron planting and it makes a considerable amount of income annually.Rhizoglyphus robini is the most harmful mite in saffron fields. This species causes corm rotting in soil which finally results in yield losses. To determine the effects of depth of planting and Summer irrigation, the present study was conducted in Gonabad Agricultural and Natural Resources Station during 1999-2005 period. The study was laid out in factorial experiment based on Randomized Complete Block Design with four replications. The experiment consisted of three levels of planting depth and four levels of Summer irrigation. Results showed that Summer irrigation significantly increased mite population and yield 1osses. Depth of planting had not any significant influence on the mite population in spring, autumn and winter, while significant increases in mite population in the depth of 10 and 30 cm were observed in Summer. Increasing depth of plantings resulted in the increasing of black spots on corms.The interaction of Summer irrigation and depth of planting revealed that applying two irrigation maximize the mite population in all depths. However the minimum levels of mite population as well as black spots were observed with no irrigation. Higher the depth of deeper the corms planted higher the number of black spots found in plots with two irrigations. Higher mite population was observed in fields with higher planting record.

This experimental was done as split plot in the basis of completely randomized blocks design with tree replication in Mazandaran province in 2009. Main factor was sowing date (August 16, 24, 31 and 7 September) and sub factor was row spacing (65, 75 and 85 cm). The results showed that the maximum plant height and plant dry weight were obtained on August 16 and most of the ear diameter, grain number per row, grain number per ear, grain weight, green ear yield and harvest index were conducted on August 24. Most of the plant height, ear length and plant dry weight were gained at rows space 65 cm and the maximum grain number per row, grain weight, green ear yield and harvest index were obtained at row space of 75 cm. Maximum of the plant height and plant dry weight were obtained on interaction effect of the 16 August and rows space 65 cm. The most amounts of green ear yield and grain yield were obtained in the August 24 and rows space 75 cm. sowing date 24 August introduced the best treatment, because in this sowing date increased ear diameter, grain number per row, grain number per ear, grain weight, green ear yield and harvest index that introduce as the most important traits of sweet corn. The Rows space 75 cm determined as the best because in this treatment grain weight, green ear yield and harvest index increased.

This experiment was conducted to study the effect of plant density and sowing season spring and Summer on quantitative characteristics and yield of corn (704 maize hybrids), Split-plot arrangement in randomized block design with three replications was used and during 2015 in Andimeshk. The different densities of 65, 75, 85 and 95 thousand plant per hectare was considered as main plots and sowing season in two levels sowing Spring (25 March) and sowing Summer (21 July) were randomized in sub-plots. Results showed that The effect of plant density on was significant in all the tested characters exception The number of active leaves and leaf fag. The effect season sowing on traits such as number of active leaves, leaf fag and 1000 grain weight were not significant. with of plant density increasing from 65 to 75 thousand plant per hectare increased fresh forage yield, but in densities Above was decreased. The highest grain yield in density of 65 thousand plant per hectare and Related was to sowing Summer. based on the findings of this experiment and in order to achieve the highest fresh forage yield in sowing spring and the plant density of 85 thousand plant per hectare in the Khuzestan and other regions with similar ecological conditions are recommended.

In order to study the effects of water deficit stress on two safflower cultivars under spring and Summer sowing conditions, an experiment was conducted in a split-split-plot layout based on a randomized complete block design with three replications in 2017 at the research farm of agriculture faculty, Islamic Azad University, Sanandaj Branch. The main factor was the sowing date including spring and Summer dates. The sub-factor was drought stress with two levels (full irrigation and interrupted irrigation at the flowering stage). The sub-sub-factor was cultivar including Sina and Faraman. The heads number per plant and seed yield in spring sowing significantly increased compared to Summer sowing. In spring sowing conditions, yield and its components were significantly decreased as the result of water deficit stress during the flowering stage compared with full irrigation however in Summer sowing conditions, stress had no effect on the above-mentioned traits. The highest rate of seed yield (3287 kg/ha) was obtained in the spring sowing of Faraman cultivar with full irrigation, and there was no significant difference between the two cultivars with respect to seed yield, under stress conditions in spring or Summer sowing conditions. According to the results of this experiment, in Summer sowing conditions there were no advantages from irrigation at the flowering stage compared with interrupted irrigation at the flowering stage, therefore in the case of shifting the sowing time from spring to Summer, it will be possible to save the water by interrupting the irrigation at flowering stage accordingly an acceptable yield may be attained as a second crop.

Summer savory (Satureja hortensis L., Lamiaceae) is a well known medicinal and aromatic plant, native to Southern Europe, Anatolia, Caucasus, Iraq and western Iran, but nowadays it is cultivated worldwide. In order to evaluate the effect of sowing date and plant density on the yield and morphological characteristics of Satureja hortensis L. a field experiment was conducted in Sary Agricultural University using split-plot design based on randomized complete blocks with three replications during 2010. Main factors were three sowing dates (11 April, 22 April and 3 May) and sub factors were three plant density (15×35, 25×35 and 35×35cm). The species were investigated at full flowering stage. sowing date and plant density had significant effects on most of the morphological characteristics. According to the results of mean comparison, the highest plant height (52.3 cm), lateral shoot (23.22 N/P), number of nod (17.81), shoot diameter (8.8 mm), root diameter (9.12 mm) and dry weight of root (2.76 g/p) were recorded for first sowing date. Delay in sowing time increased the dry shoot yield significantly as the highest dry shoot yield (3023.1 and 2663.9 kg/ha) was obtained at third and second sowing time. The result of mean comparison showed that the highest root diameter (9.33mm) and dry weight of root (2.56 g/p) were recorded for third density. In addition, the highest plant height (53.03 and 51.09 cm), lateral stem (21.94 and 21.79 N/P), number of nod (17.06 and 16.32) and shoot diameter (7.92 and 7.4 mm) were obtained at third and second densities. Plant density had no significant effect on dry shoot yield. The obtained results showed that morphological characteristics of Satureja hortensis were affected by agronomic treatments and growth performance may be enhanced by proper management.

In semi-arid regions e. g. Iran, water is the major limiting factor for the growth and yield of sugar beet. Development of cultivars with flexible growth period, dependent on the environmental condition, is one of the methods to reduce water usage for sugar beet cultivation. The present study was performed in Sugar Beet Research Station of Motahhari, Karaj, Iran as a split factorial based on a randomized complete blocks design with four replications in two years (2015-16). Main plots were devoted to sowing date (mid-April and late-June), and sub-plots to the factorial combinations of three harvest dates (12 October, 1 November, and 21 November) and six genotypes including promising hybrids (7112*261)*5RR-87-HF. 33 and 261*276. P. 77. SP. 19 and commercial cultivars Pars, Jolgeh, Paya and IR7. Potential root yield (RY) and sugar yield (SY) was reduced by 3. 5-3. 8% per week owing to delay in sowing. The significance of sowing date × genotype interaction (P<0. 05) highlights diverse response of various genotypes to the shortening of the growth period. Superior genotypes for delayed planting were identified based on the combination of two components of the least response to delayed sowing as well as achieving the highest yield under delayed sowing condition in terms of SY as Paya, IR7, and Pars. Although the direct effect of harvest date on RY, SY, and sugar content (SC) was not significant due to the significant interaction of year × harvest date, however in general, it increased RY, SY, and SC by 21, 38, and 1. 72 %, respectively via delaying the harvest date from 12 October to 1 November 1 in 2015. Therefore, the harvest date of 1 November was the most suitable time for sugar beets harvest in Karaj region. Non-significant interaction between sowing and harvest date for various studied traits indicated that the impacts of delay in sowing cannot be offset by delay in harvest. Overall, results showed that by each single day advancement in sowing (between mid-April and late-June) RY and SY increased by 400 and 50 kg ha-1, respectively and for each day delay in harvest (between 12 October and 1 November) RY and SY were increased by 370 and 100 kg ha-1, respectively.

Introduction13 Given recent droughts, Medicago scutellata Var. Rabinson has taken an important position in crop rotation, especially in semi-arid regions. Therefore, agronomy management factors play an important role in improving its growth. Also, regarding its short growth period length, its quantitative and qualitative forage yield has been high, and it can be sown through dry-farming in regions with 300-500 mm of rainfall. On the other hand, given the importance of forage cultivation in agriculture and water shortage in Iran, we can try to cultivate fallow lands. The aim of this study was to evaluate the effect of different agronomic management methods on the quantitative and qualitative snail medic forage yield and to compare the relative contribution of components to increasing it under the climate of Arak. Materials and Methods In this study, two sowing dates (July 15 and 22, 2017) as main plot, two sowing depths (1-2 and 2-4 cm), and four seeding rates (2. 5, 7. 5, 12. 5, and 17. 5 kg ha-1 equal to 20, 50, 80, and 125 plants m-2) as subplots were investigated. The experiment conducted in split plot factorial based on randomized complete block design with three replications. It is noteworthy that due to seed hardness, the average number of germinated seeds was low. The measured traits in this study included forage dry weight, stem dry weight, pod dry weight, leaf dry weight, number of pods per m2, leaf area index (LAI), dry mater digestibility (DMD), crude protein (CP), crude fiber (CF), crude ash (CA), acidic detergent insoluble fiber (ADF) and neutral detergent soluble fiber (NDF) in the final stages of forage harvesting. Finally, using the statistical software SAS, we performed analysis of variance, comparison of means using Duncan’, s multiple range test at 5% probability level and correlation analysis. Results and Discussion The results showed that the highest dry forage weight and dry stem weight (2884. 13 and 1361. 71 kg. ha-1, respectively) were observed in the treatment of seeding rate of 12. 5 kg ha-1, at sowing depth 1cm and on the sowing date of July 21. Accordingly, the amount of dry forage obtained from the sowing date of July 21 and the sowing depth of 1 cm was 10. 77 and 19. 84% more than that of the sowing date of July 5 and the sowing depth of 2 cm, respectively. The portion of dry stem weight in the sowing date of July 21 and sowing depth of 1 cm was 53. 96 and 55. 24% of the dry forage weight, respectively. Furthermore, the portion of the pod and dry leaf weights from the dry forage for sowing date of July 21 were respectively reported as 34. 13 and 11. 91%, and for sowing depth of 1cm were, respectively, 33. 56 and 11. 18%. As the amount of seeding rate increased, the CF increased, and the percentage of CP decreased. By taking into account the absolute value of the slope value of the equations of these two traits, it was found that the effect of density on the CF is more than the effect of this treatment of CPP. According to the obtained results, the sowing date of July 21, the sowing depth of 1 cm, and the consumed seed of 12. 5 kg ha-1 showed an appropriate quantitative and qualitative yield. Also, according to the results of the correlation test, it was determined that the dry forage produced had a positive correlation with the stem dry weight (0. 99**), the pod dry weight (0. 99**), the leaf dry weight (0. 98), the number of pods per m2 (0. 43*), the CA (0. 71**), DMD (0. 78) and NDF. On the other hand, a negative correlation was found with LAI (-0. 66**) and ADF (-0. 53**). Conclusion Regarding the absolute value of the slope in the equations pertaining to these two properties, it was found that the susceptibility of fiber percentage to density was higher than the susceptibility of crude protein percentage in this treatment. In deeper sowing, the obtained protein percentage was 1% lower, while the lowest fiber percentage occurred in shallow sowing. Generally, we can say that this crop has a high sensitivity to high densities. Based on the results, there were the relation between regression and correlation results.

Introduction: Climate change due to global warming is a worldwide concern and is expected that high temperature and its negative effects on agricultural crops will increase in coming years. Soybean is one of the most important oil seed crops that also provides protein around the world. To optimize production of soybean in each region, it is necessary to use adapted improved cultivars and growing season duration for growth and development of the crop. Temperature is one of the environmental factors that affects the phonological stages and seed yield of soybean. Material and Methods: To evaluate the effect of sowing date and genotype on seed yield of soybean genotypes a field experiment was carried out as split plot arrangements in randomized complete block design with three replications in Safiabad Agricultural and Natural Resources Research and Education Center of Dezful in Iran in 2017 and 18 growing seasons. The main plots were consisted of three sowing date (22nd June, 6th July and 21st July) and eight soybean genotypes; SF1, SF2, SF3, SK93, M13, SG4, SG5 and Salend, were randomized in sub-plots. Results: Combined analyisis of variance showed that the flowering duration, growth duration and grain filling duration were affected by sowing date and genotype. Maximum temperature on the first sowing date (22nd June) was higher than the second (6th July) and third (21st July) sowing dates during reproductive stages and seed filling periods. The pod number plant-1 decreased by 3.37 pods with one degree centigrade increase in temperatures above 35 ˚C. Mean comparison of sowing date × genotype interaction revealed that the highest number of pod.plant-1 (88 pods) related to the second sowing date (6th July) and SK93 and M13 genotypes. The lowest number of pod.plant-1 (26.5 pods) belonged to the first sowing date (22nd June) and SF2 genotype. In 2017, the highest seed yield (3473 kg.ha-1) obtained from the second sowing date (6th July) and SK93 genotype. However, the maximum seed yield (3559 kg.ha-1) belonged to the third sowing date (21st July) and SK93 genotype. The lowest seed yield related to the first sowing date (22nd June) and SF2 genotype with 968 kg.ha-1 and 2080 kg.ha-1 in the first and second year, respectively. Seed yield in the first sowing date (22nd June) and second sowing date (6th July) decreased by 16.5% and 8%, respectively, compared to the third sowing date (21st July). The highest (25.6%) and the lowest (18.7%) seed oil content belonged to the third sowing date (21st July) and SK93 and SF3 genotypes, respectively. Conclusion: The high temperature is a serious limiting factor for Summer grown soybean in the nort Khuzestan. Selection of indeterminate soybean genotypes, due to the longer flowering duration, can be an appropriate crop management strategy to reduce the negative effects of high temperature during the flowering period, and consequently achieve higher number of pod.plant-1 and seed yield in the north Khuzestan environmental conditions. The results of this experiment and high temperatures during reproductive stages of soybean in different sowing dates, the sowing date window of 6th July until 21st July and SK93 genotype was identified as a suitable crop management strategy for the North Khuzestan.