triticum aestivum

To optimize the grain filling period of commercial wheat cultivars, an experiment was conducted at two agricultural research stations in the warm and humid agro-climatic zone of northern Iran. The experiment was conducted as a split plot with four replications. The main plots consisted of five sowing dates: 1 November (SD1), 16 November (SD2), 1 December (SD3), 16 December (SD4), and 31 December (SD5), and four spring wheat cultivars, namely Ehsan, Tirgan, Meraj, and Kalateh, were the subplots. The results indicated that the highest yield was obtained from SD3 (5892.2 kg ha-1). Despite the one-month difference between SD1 and SD3, the grain filling period remained unaffected, providing suitable conditions for plant height and resistance to lodging across the different cultivars. At SD3, optimal conditions were established for the wheat cultivars regarding temperature, day length (DL), relative humidity (RH), and energy use efficiency during the grain filling period. Both SD2 and SD3 exhibited the highest energy use efficiency. The grain yield at SD1 decreased due to severe plant lodging, while exposure to terminal heat and drought stresses, and shortened grain filling period reduced yield at SD4 and SD5. For the early anthesis cultivar, i.e., Kalateh, the grain yield was significantly higher than that of the other cultivars. The grain filling period for the early anthesis cultivar was not significantly different from the others, allowing the plant to escape terminal heat and drought stresses, thereby increasing energy use efficiency and, consequently the grain yield. Therefore, the early anthesis cultivar is highly suitable and recommended for cultivation in the studied zones where terminal heat and drought stresses are prevalent at optimal sowing dates.

The study attempts to analyze the energy input-output relationship during Iranian wheat project from 1990 to 2005. The main sources of evidence for this investigation were obtained from the related companies and different departments of Iran Ministry of Jihad–e–Agriculture including Library. Findings revealed that total energy inputs and output have increased from 26503.5 and 20871.5 MJ ha-1 in 1990 to 35466.3 and 30259.8 MJ ha-1 in 2005, indicating a 25.27 and 31.03% increase, respectively. Averagely data collection (under both irrigated and dryland conditions), diesel had the highest share, of 37.08%, followed by electricity (21.23%), chemical fertilizers (20.21%), water (8.39%), seed (7.94%), machinery (2.33%) and human labor (2.18%), respectively. There was a significant increase in electricity usage (about 74% increase), and an associated decrease in the diesel usage (about 34% decrease) during 1990-2005 period because electric pumps replaced diesel pumps. Chemical fertilizers rose from 4353.25 to 8659.80 MJ ha-1. In the studied period, the share of nitrogen and potassium in the total fertilizer energy input increased from 72.00 to 84.79% and from 0.00 to 0.65%, respectively, while the share of phosphorus shrunk from 28.31 to 14.56%. There were not significant changes regarding the human labor and machinery annually and seedbed preparation required the maximum energy, followed by harvesting. Pesticides increased extensively in the last year under study, particularly in case of herbicides, and of which 2,4-D/MCPA and Clodinafop-propargyl had the highest share. Values of energy use efficiency (0.70-1.00), specific energy (14.70-21.04 MJ kg-1) and energy productivity (0.05-0.07 kg MJ-1) showed an intensive use of inputs not accompanied by increase in output during wheat project. Most of the total energy inputs were supplied in the non-renewable and direct forms. Also, regression analysis indicated the impact of indirect and non-renewable energy on output was statistically significant.

This article describes the results of a study on the effect of pre-sowing treatment of Triticum aestivum L. seeds with stevioside (10-8 M) for 24 h on the activity and molecular heterogeneity of lectins in seedlings at low positive temperatures. Phytolectins take part in a wide range of physiological processes in plants, regulating not only growth, but also increasing resistance to salinity, heavy metals, and temperature stress. In this regard, the study of changes in the activity and heterogeneity of these molecules in the search for new regulators of plant growth and development is urgent. The observed stevioside-induced increase in the activity of lectins bound to the cell wall and changes in their qualitative and quantitative composition against the background of temperature stress may indicate an increase in the adaptive potential of wheat plants.