In order to investigate the possibility of quinoa producing in Garmsar, Iran, a factorial experiment conducted in randomized complete block design with three replications in 2018-2019 growing season at Garmsar Agricultural Research Station. The factors were Planting date at three levels (March 6th, April 1st and April 6th) and the three genotypes of quinoa (Q26, Q29 and Titicaca). Results showed that the effect of Planting date was significant for all studied traits except the harvest index. Also, all studied traits were significantly different in all genotypes. Titicaca planted on March 6th had the highest yield (2276 kg.ha-1).The grain yield and yield components decreased with the delaying the Planting date. Compared to early Plantings, Latest date, April 6th, led to reduction of all traits, especially grain yield (about 50%). The results of simple phenotypic correlation between the studied traits showed that grain yield per hectare had the highest correlation with plant yield (0.877) and then with leaf area index (0.832), panicle weight (0.815) and number of branches per plant (0.745) that was significant at the 1% probability level.

An experiment was conducted as a split - split plot in form of a randomized block design with four replications in Cilakhor region of Iran in 2004. The main factor was the seed Planting date with three levels (5, 12 and 25 April), sub factor was the crop density with two levels (160,000 and 250,000 pI/ha) and sub-sub factor was the crop arrangement with two levels (equidistant and non-equidistant). Delaying the Planting date caused the increase of biological yield and decrease of harvest index. Increasing the crop density caused the increase of the number of fertile heads per square meter, biological yield, grain yield, and decrease of the number of fertile tillers, the number of grains per head, dry weight of above-ground organs per hill, yield of each hill (P<0.05) and the plant height, the number of grains per head was decreased.

The present study was conducted in split factorial based on RCBD with four replications at Behbahan Agricultural Research Station during 2011-13 cropping seasons, to determine the suitable sowing date in nursery and plant density in farm for improved population of Behbahan onion. Main plots consisted of four Planting dates 6 September, 21 September, 6 October and 21 October. Sub plots were combination of three row spacings (20, 30 and 40 cm) and three plant spacings (5, 7.5 and 10 cm) as factorial. Earliest time of bulbing was estimated using bulbing ratio and statistical method of cusmus. In the first year bulbing occurred between photoperiods of 12 h and 3 min (17 March) and 13 h and 16 min. (27 April). In the seconed year bulbing occured between photoperiods of 11 h and 35 min. (1 March) and 12 h and 46 min. (9 April). Bulbs were harvested when 50-80% of top foliage had fallen and collapsd. Planting date of 21 September produced the highest yield (52.62 tha-1), however difference of yield between Planting dates of 6 and 21 September was not significant. Planting date of 6 September had the maximum bolted plants (17.5%). By delay in Planting date, bolted plants percent was decreased. Yield of plants with 20 cm row spacing (51.52 tha-1) and 5 cm plant spacing (47.92 tha-1) was higher than plants with the other row and plant spacings. Reduced Planting density decreased bolted plants percent. According to the results, sowing of improved population of Behbahan onion on 21 September in nursery and transPlanting with 20× 5 cm distance (100 plants per m2) is recommended for behbahan area.

In order to study the effect of different Planting dates and application of ammonium sulphate on yield and yield components of Hyola rapeseed cultivar in winter Planting an experiment was conducted in climatic conditions of Mane and Samalghan during 2008-2009. The experiment was carried on factorial based on CRBD with four replications. The experiments were treatment included three Planting dates (18 Sep., 4 Oct. and 19 Oct. of 2008) and four fertilizer treatment (base fertilizer 100 kg/ha urea, 80 kg/ha ammonium sulphate at beginning of spring and 80 kg/ha ammonium sulphate in maximum height of plant), (base fertilizer 100 kg/ha urea, 40 kg/ha ammonium sulphate at beginning of spring and 40 kg/ha urea in maximum height of plant), (base fertilizer 100 kg/ha urea, 40 kg/ha urea at beginning of spring and 80 kg/ha ammonium sulphate in maximum height of plant) and (base fertilizer 100 kg/ha urea, 40 kg/ha urea at beginning of spring and 80 kg/ha urea in maximum height of plant).Trait were considered as number of seed per pod, number of pod per plant, 1000 grains weight and grain yield.The results showed that second Planting date was superior on number of seed per pod, number of pod per plant and grain and value of third fertilizer treatment on number of pod per plant, grain yield. Highest and lowest grain yield belonged to the second Planting date and third fertilizer treatment with average 4.1 ton/ha and third Planting date and fourth fertilizer treatment with average 3.2 ton/ha respectively.

Nitrogen limitation is on of the most important factors of yield production in the field crops. Application of nitrogen fertilizer in addition of reduction in economical output, induces environmental pollution. This investigation was carried out in research field of Karoun Agriculture and industrial Co. which is located at Shoushtar. Effects of Planting pattern (0.9,1.2 and 1.5 m interrow), dat of Planting (22 Aug, 20 Sep and 19 Oct) and application of nitrogen (0,100,200 and 300 kgNha -1 on nitrogen use efficiency, nitrogen uptake efficiency and nitrogen utilization efficiency in sugarcane (Saccharum spp) were studied in a strip split plot design with four replications. The final results indicated that relative nitrogen content were increased by high of fertilizer applications. Low plant density and nitrogen application decreased nitrogen uptake. Low plant density, late plantig and high fertilizer application resulted in low nitrogen use efficiency, also nitrogen uptake efficiency were decreased significantly in low density and high nitrogen application treatments. Nitrogen utilization efficiency on the basis of sugar yield were increased in low density, early Planting and low nitrogen application treatments.

To evaluate effect of photosynthate availability under terminal heat stress on yield and yield components of wheat, this research was conducted in a split plot experiment based on randomized complete block design (RCBD) with three replications at the Research Farm of Islamic Azad University of Ahvaz in 2015 cropping season. Treatments were defoliation in four levels: removal of two upper leaves, flag leaf removal, complete removal of spikelet at one side of spike and control (non-manipulated) which assigned to main plots and three Planting date including (Nov.21st, Dec.5st and Dec.21st) to subplots. Results showed that defoliation had significant effect on number of grains/spike, 1000 grain weight, grain yield, biological yield and harvest index at one percent probability level. Planting date also affected number of spike/m2, number of grains/spike, 1000 grain weight, grain yield, biological yield, and harvest index significantly at one percent probability level. The interaction effect of defoliation and Planting date on the number of grains/spike, 1000 grain weight, grain yield, biological yield and harvest index was also significant. The highest grain yield (5691 kg.ha-1) belonged to the control treatment (no defoliation) at first Planting date (Nov.21st). This was due to the not coinciding filling periods to terminal heat stress of growing season where maximum assimilates were produced. The lowest grain yield (2123 kg.ha-1) belonged to delayed sowing and removal of spikelet at one side of spike. Maturity of plants during 3rd Planting date (Dec.21st) was coincided to heat stress and thus reduced assimilate production.

To evaluate the effect of seed priming on plant establishment and to determine the optimum Planting date and plant density of silage corn, SC 704, in summer late Planting, an experiment was carried out as split-split plot based on randomized complete block design with four replications in Agriculture Research Center of Gharahkeil, Qaemshahr, Mazandaran Province, Iran, during two years, 2010 and 2011. The experimental factors were including two levels (27 July and 7 August) of Planting dates as main plots, two levels of plant density (7 and 9 plants per m2) as sub-plots and four levels of seed priming (pure water, PEG-8000, KNO3 and control) as sub-sub-plots. Results showed that forage dry yield and ratio of ear to total dry weight were higher in 2010 than 2011. With the delayed Planting, forage dry yield and ratio of ear to total dry weight had decreased 31.7% and 18.2%, respectively. Furthermore, forage dry yield had increased 21.4% with the increasing of plant density. The seed priming with PEG also increased the ratio of ear to total dry weight. In total, results of this research indicated that the seed priming with PEG using late summer Planting in August and density of 90000 plants per ha is possible to produce the high quality forage in silage corn.