JOURNAL OF CROP PRODUCTION RESEARCH (ENVIRONMENTAL STRESSES IN PLANT SCIENCES)
Year:2012 | Volume:4 | Issue:3|Papers Count:8

In order to study the effect of planting dates on yield and yield components on nine sweet corn hybrids, an experiment was conducted at four locations (Karaj, Mashad, Gorgan and Varamin), in 2007. The experiment was carried out using factorial design lay out in a randomized complete block (CRBD) with four replications in two planting dates (May 21 and June 11). Analysis of variance showed that the difference among hybrids and also effect of location and interaction between location and planting date were significant (P<0.01) for all of the traits. Planting date for traits ear number and seed yield at 1% probability level and for the other traits was significant at 5% probability level. From the results of this experiment it should be concluded that in order to obtain the highest yield, sweet corn might be planting until May 21. Delay in cultivating caused decreasing in yield in Gorgan region. In Karaj, Mashad and similar regions, it is possible to planting sweet corn until June 11. In Karaj, hybrids Obsession, Ex08716636, Chase, Temptation and Challenger had more yield than the others and can be recommended for this region. Similarly, hybrid Obsession for Gorgan, Chase and Temptation for Mashad, and Chase, Basin and Power house for Varamin can be recommended.

In order to determine the effect of drought stress in some morphological traits in bread wheat an experiment was conducted in 2011-2012 with four cultivars including "Parsi, Chamran, Roshan and Kavir". The experimental design was split plot in which the water conditions placed in main plots and varieties in sub plots. The analysis of data showed that the tiller number, fresh weight, dry matter, plant yield, 1000 seed weight and yield per unit area are strongly affected by water condition. Also the varieties showed a significant difference in leaf area, tiller number, fresh weight, dry matter, plant height and yield. There was a significant interaction effect between water condition and variety for dry matter. Simple regression showed there is a significant relationship between leaf area, tiller number, wet weight, dry matter, plant height, yield per plant and 1000 seed weight as independent traits with yield as dependent variable, but there was not a significant relation between total root length and stem diameter as independents traits with yield.

To review and determine the most suitable varieties and planting date of soybean, the research project was conducted in 2009 and tested as a split plot in the basis completely randomized blocks design with three replications as a joint project between Shahed University and Heart University in Herat Province, Afghanistan. The main plots consisted of three planting dates (20th of May, 5th of June and June 20th) and subplots consisted of four cultivar (C1, C3, M4, L17). The results showed that the effect of planting date and cultivar and their interaction on oil yield, protein percentage, grain yield, stem and leaf dry weight were significant at one percent level. In planting date delaying, all traits showed a decline in cultivated varieties. Maximum number of lateral branches seed number (5) was achieved on May 20th and on June 5th by C1 variety (45). The highest seed yield and oil content of the M4 achieved on May 20th planting date, the C3 on fifth of May, and the maximum percentage of the protein was generated by C3 on May20th planting date.

In order to study zeolite and nitrogen application on yield and yield components of rice (Oryza sativa L. var Hashemi), an experiment was carried out as a randomized complete block design in factorial arrangement with three replications at Astaneh-Ashrafieh, Iran in 2012 growing season. The treatments were included: zeolite (0, 6, 12 t.ha-1), nitrogen fertilizer (0, 100, 200, 300 kg.ha-1) from urea (46% N2). The results showed that the effects of zeolite and nitrogen were significant on all of traits except number of empty spikelets per panicle. So, interaction effects of treatments were significant except of height of panicle and number of filled grain in panicle. The highest grain yield was achieved by 12 t.ha-1 of zeolite (3795.11 kg.ha-1), 300 kg.ha-1 of nitrogen fertizer (3815.28 kg.ha-1) and 12 t.ha-1 zeolite+200 kg.ha-1 nitrogen fertizer (4516.3 kg.ha-1).

Rhizomania is known as the most destructive disease of sugar beet in the world. Most sugar beet soil borne pathogens are developed by soil moisture and heat. One of the recommended ways to reduce disease damage in the infested areas is avoiding of excessive moisture which provides favorable conditions for disease development. It is essential to conduct experiments to evaluate the relationships between water consumption, sugar beet yield, and rhizomania damages. Therefore, this experiment was performed in an infested field at Zarghan station of Fars Research Center for Agriculture and natural Resources in 2010. The research was conducted in the form of a split plot experimental design with the base of randomized complete block design with three replications. Main plots were sugar beet cultivars including 28064, 28058, 28928, Zarghan, Jam, and Rasool (control treatment). Subplots were applying three levels of irrigation regimes using line source sprinkler system. Irrigation regimes were set up based on the distance from the lateral tube and distance of four meters was considered for irrigation pipes. The results showed that 28928 hybrid had better root yield (31.44 t/ha) and sugar yield (5.29 t/ha) compared to the other cultivars. In low infestation, the deficit irrigation can be useful if using tolerant cultivar, but in high infestation, the effect of irrigation management was nil. Deficit irrigation apparently did not reduce disease damage but, Elyza test and OD (Optical Density) determination showed that deficit irrigation reduced OD and increased healthy roots. Maximum yields and water use efficiency were produced in optimum irrigation with 5.91 kg/m3 water that it is not significant with mid stress with 4.95 kg/m3 water. The maximum water use efficiency related to 28928 and 28058 hybrids that statistically belong the same group. In this experiment, hybrids 28928 and 28058 were proposed for the future study in this area.

Thyme (Thymus vulgaris L.) is a perennial herbal plant, belonged to Lamiaceae family. To evaluate the effect of Fe and Zn foliar application in thyme on yield and essense production, the investigation was performed in complete randomized design by 2 factores (Fe, Zn) with 3 replication in pots, under farm conditions. The used factor in this research included iron and zinc in 3 levels (0, 2 and 4 ppm) as soloution spraying. Chromatograms resulted showed thymol and carvacrol percentage following harvesting and drying plant and extracting and mixing it’s concentrate with metol 70% and injecting samples in HPLC machine. The obtained results from this study indicated that concentration of 2 ppm, among iron and zinc treatments effects significantly on traits. The results show significant increasing in root lengnts and side branch numbers. The most thymol (0.31%) and carvacrol (0.25%) produced by 2ppm of zn and fe (Fe1Zn1). There was a significant difference between other measured characters. In most of them Fe1Zn1 was the best. Perhaps. Because of antagonist effects between fe and zn, their upper concentration consumption may creating undesirable effects.

Mixed cultivation is one of the efficient systems in increasing productivity and utilizing of the production resources. In this domain, an experiment was carried out on a farm in khoy in 2012. This research was done as factorial in the basis of completely randomized blocks with three replications. The first factor included four systems of the pumpkin pure culture, pure culture of pinto bean and the culture of pumpkin in 2 and 3 rows of pinto bean. The second factor included the seed inoculation with biofertilizers of nitroxine, nitragin and lack of seed inoculation. The results of the experiment showed that the main impact of the experimental factors on the traits of the pumpkin was meaningful and in the interactive impacts, only the 100 seeds weights and seed yield of the squash was significant, so that the inoculation of pumpkin seeds with nitroxine and nitragin caused the improvement of functional traits of seeds and also the highest yield of pumpkin with 130.2 gr/m2 was attained. Pure cultivation, in comparison with the used mix ratios in this research in relation with the number of fruits on the bush, the number of seeds in the fruit, and yield of pumpkin seeds showed the best condition, but regarding the quantities of the land equality ratio (LER) the mixed culture of pumpkin with three rows of pinto bean showed the highest amount (1.52). It indicates the profitability of pumpkin and pinto bean mixed cultivation in economic utility of soil and water production resources.

In order to study the efficacy of Foramsulfuron+iodosulfuron+isoxadifen-ethyl to control weeds in corn, an experiment was conducted during 2011 in Varamin and Karaj. Treatments were arranged in a RCBD design with four replications and 11 treatments as Nicosulfuron at 2 lit.ha-1, Bromoxynil+MCPA 1.5 lit.ha-1 plus hand weed of grasses, 2,4-D+MCPA at 1.5 lit.ha-1 plus hand weed of grasses, Rimsulfuron at 50 g.ha-1+Citogate at 0.2%, Foramsulfuron at 2.5 lit.ha-1, Nicosulfuron +Rimsulfuron at 175 g.ha-1, mix of Bromoxynil+MCPA at 1 lit.ha-1+ Nicosulfuron at 1.5 lit.ha-1, Foramsulfuron+iodosulfuron+isoxadifen-ethyl at 1.25, 1.5, 1.75 lit. ha-1 and weed free control. Different factors of weed and corn including, damage of treatment to weeds and corn, weed population and dry matter reduction were evaluated 30, 60 days after spraying. Grain yield and yield components were measured at harvest stage. The results indicated that mix of Bromoxynil+MCPA plus Rimsulfuron was the best treatments (more than three folds) to weeds control and produced the highest corn grain yield in Varamin, also the results indicated that Foramsulfuron+iodosulfuron+isoxadifen-ethyl 1.75 lit.ha-1 that was the best treatment (more than four times) to control weeds in Karaj and produced the highest corn grain yield. The efficacy of Foramsulfuron+iodosulfuron+isoxadifen-ethyl at 1.5 lit. Ha-1 was similar to Nicosulfuron and Nicosulfuron+Rimsulfuron on borad leaves weeds as well as some grasses.