نشریه فیزیولوژی گیاهان زراعی
پیاپی 20 (زمستان 1392)

The analysis of plant response to environment changes and field managements such as change of planting date based on mathematical patterns is evaluated an effective technique to predict yield. This research was carried out in with 27 genotypes 2010-11 cropping year and with 15 genotypes in three groups late, mid and early maturity in 2012-13 cropping year in Khuzestan Agriculture and Natural Resource Research Center. Each group in each year was investigated as split plots in an independent experiment using complete randomized blocks statistical design with three replications. In each experiment plantings, the date and the wheat genotypes were placed in the main and sub plots, respectively. The Chamran cultivar was considered as the control for all the three groups. In the first and the second year of research, the first planting date for late maturity group were Oct.12 and Oct.27 and for the early maturity group were Dec.11 and Dec.16 and the other two planting dates in each experiment were applied with 10 days interval and for the mid maturity group the first planting date in the first and second year were Nov.11 and Nov.6, respectively and the other two planting dates were applied in the first year with 10 interval and in the second year with 15 days interval. The changes trend of grain yield in each group was investigated in response to planting date change using regression methods and the optimum point of the planting date was calculated based on the maximum grain yield based on differentiable function compared to planting date(dGY/dX). Results showed that in late and mid maturity genotypes, the function of grain yield followed quadratic polynomial trend with strongly R2. In early genotypes, the variations trend of grain functions was a decreased linear trend as a result of delay in planting. As by distance from the first planting date, the grain yield decreased by the amount of 87 kg per hectare in the day.

Salinity tension is a growing problem in agricultural soils. In order to investigate the interaction of Na+Ca2 on biomass and antioxidant enzymes activity of peroxidase and polyphenol oxidase in leaf of barley, this research was conducted as a completely randomized design with three replications in greenhouse conditions (temprature 25°C, 35 percentage relative humidity and 16 hours lighting photoperiod). The seedlings were treated by levels zero, 50, 100 and 150 mM of NaCl and with levels zero, 6 and 10 mM of CaCl2 one week after planting seeds in soil. After five weeks applying the treatment, some morphological and physiological parameters including dry weight of shoot and root and peroxidase and polyphenol oxidase enzymes activity in leaf were assessed. Results showed that salinity tension significantly decreased the dry weight of shoot and root, however, increased the peroxidase and polyphenol oxidase enzymes activity in leaf. While, adding calcium to salty environment significantly increased dry weight of shoot and root yet decreased peroxidase and polyphenol oxidase enzymes activity in leaf. Calcium decreased the harmful effect of salinity tension and the maximum ameliorative effect of calcium was observed in 6 mM CaCl2 concentration.

The yield of chickpea in Iran is low in comparison with other countries. One of the most important effective factors, is no application of optimal plant density and chickpea cultivars difference in response to plant density. In order to investigate the effect of plant density on yield and some physiological indices of chickpea cultivars, this experiment was conducted as factorial based on randomized complete blocks design with three densities 25, 35 and 45 plants in m-2 and three chickpea cultivars Jam, ILC-482 and Kaka at three replications at the research farm of Agriculture College of MohagheghArdabili University. The highest grain yield and the total dry matter accumulation in m-2 belonged to Kaka cultivar treatment combination in density 45 plants inm-2 and the lowest to density 25 plants in m-2 to Jam cultivar. The trend of crop growth rate and relative growth rate was similar to total dry matter. The results showed that plant density had significant effect on 100-grainweight, grains number per pod, pods number per plant, grains number per plant and grain yield .The highest grain yield was produced in Kaka cultivar with density 45 plants in m-2 and the lowest in density 25 plants in m-2 in Jam cultivar. So, it could be suggested that in order to increase the grain yield, total dry matter accumulation and the other physiological indices such as crop growth rate and relative growth rate, Kaka cultivar should be applied at density 45 plants in m-2.

In order to investigate the freezing tension effect and evaluation of its tolerance in wheat Sayonz cultivar at 4 to 6 leaf stage, under controlled conditions, an experiment was carried out as completely randomized design with three replications at the Agricultural Faculty of Ferdowsi University of Mashhad. Six levels of freezing temperature (zero, -4, -8, -12, -16 and -20 C˚) were considered as investigating treatments. In order to induce acclimation in plants, they grow in natural conditions, since planting time to 4-6 leaf stage. To apply freezing treatments, they were placed then in thermogradyan freezer. To assess tolerance to freezing temperatures some traits such as the primary ion leakage, the secondary ion leakage, percentage of electrolytes leakage, survival percent, number of leaves, green leaf area and plant dry weight were considered. The results showed that the effect of different freezing temperatures on the traits of the primary ionic leakage, the percentage of electrolytes leakage, number of leaves, green leaf area and plant dry weight was significant at statistical level one percentage as well as the survival percent was significant at statistical level five percentage. Based on the obtained results the highest and the lowest rate of electrolyte leakage of plant cells with the averages of 78.73 and 24.56 percents were related to temperatures -20 and -4 C˚, respectively. Also, the lowering temperature of 50 percentage survival plants (LT50su) was obtained at -18.1 C˚.

In order to investigate the effect of types of mulch and sowing depth on partitioning and remobilization of assimilates in chickpea ILC481 cultivar, this experiment was carried out as split plot based on randomized complete block designs with three replications at research farm of Campus of Agriculture and Natural Resources, Razi University of Kermanshah in 2011-2012 cropping year. Main plot were mulch treatments including control treatment, corn stubble mulch, wheat stubble mulch, farmyard manure mulch, soil mulch (using sweep) and supplementary irrigation (one irrigation in order to investigate the effect of types of mulch as well as comparison to the ideal conditions) and sub plot was planting depth (4, 8 and 12 cm). The results of experiment showed that there was significant difference between different sowing depth and mulch treatments regarding to amount of grain yield and number of grain per square meter at main stem. Grain yield at main stem of wheat stubble mulch, soil mulch, corn stubble, farmyard manure and supplementary irrigation increased 43, 24, 23, 22 and 218 percent compared to the control (without mulch), respectively. There was significant difference between different sowing depths regarding to the portion of stem remobilization in yield and the efficiency of stem in the dry matter transition to the grain. The portion of stem efficiency at dry matter transition to the grain in 4, 8 and 12 cm sowing depth was 11.38, 8.2 and 5.11 percent, respectively. In general, the efficiency of remobilization assimilates of stem to grain and the role of remobilization in yield reduced by increasing the sowing depth and using the mulching treatments.

This research was carried on in order to investigate the response of wheat cultivars to salinity tension as factorial experiment and in complete randomized block design in four replications in Islamic Azad University Shoushtar Branch. In this experiment the response of nine wheat cultivars including Chamran, Karchia66, Mahoti, Roshan, Alvand, Kavir, Ghods, Atrak and Tjan at vegetative growth stage in three salinity levels of water irrigation zero (control), 6 and 12 ds m-1 was investigated. Results showed salinity tension decreased seedling dry weight, chlorophyll concentration, leaf K concentration and leaf Kﳖ ratio of wheat cultivars. While, malondealdehid concentration, leaf Na concentration and leaf solution carbohydrates concentration increased under effect of salinity tension. The highest salinity tension tolerance index was observed in Mahoti and Karchia 66 cultivars (0.0089 and 0.0087, respectively). While, Ghods cultivar allocated the minimum amount of this index (0.0028). Karchia 66 and Mahoti cultivars had the highest seedling dry weight at 12 ds m-1 salinity level in comparison with other cultivars.

In order to evaluate the effect of salinity on some traits in different cultivars of barley at different growth stages, this experiment was conducted in vitro and field culture environment in Sadough research farm, dependent to Salinity Research National Center in cropping year 2012-2013. The germination of Afzal, Nosrat, Reihan, 4shoori and Rodasht cultivars in response to different levels of salinity 5, 10, 15, 20 and 25 dS.m-1 and distilled water as control was studied in vitro culture as factorial based on completely randomized design with three replications. The results showed that the greatest germination reduction was at salinity level of 20 dS.m-1. Also, among the tested cultivars, cultivars of Afzaland and 4Shoori with 58.6 percentage and 58.53 percentage presented the percent of germination comparing to the other cultivars, respectively. Experiment in the culture of field was conducted as split plot based on randomized complete blocks design with four replications. Different salinity were applied at main plots and five under-investigating cultivars in subplots at three levels including the amounts of 4, 8 and 14 dS.m-1. Effect of salinity treatment on all understudying traits (except spike length) was significant at one percentage probability level and five percentage probability level on spike length. Although most of the traits decreased due to salinity tension, but applying salinity increased sodium and potassium of grain. Grain yield decreased and the cultivars showed significant difference, by increasing salinity tension. The salinity interaction in cultivar showed the lowest yield in 14 dS.m-1 salinity Nosrat, Reihan, 4shoori and Rodasht cultivars and Afzal cultivar was superior in the salinity than other cultivars.

This experiment was done in order to determine superior lines and to introduce the cultivars with high performance and productive potentiality of wheat. In this research 17 selective advanced lines from the yield comparison experiments were investigated in the Kabotarabad region of Isfahan, in comparison with Bahar cultivar as control, in a complete randomized blocks design with three replications in 2011-2012 cropping year. Quantitative traits assessed were including plant height, flag leaf length, leaves number, spike length, peduncle length, tillers number and grain yield. The obtained results of variance analysis of the tested traits showed that studied lines had significant difference at one percentage probability level as compared with control cultivar and with each other. The maximum height of plants was belonged to line No.12 with 105 cm and the least height of plants was allocated to lines No. 4, 9 and 10 and with 87.6, 88 and 87.6 cm, respectively. Also, based on the obtained results of comparing the average grain yield, it was determined that the highest grain yield was line No. 18 with 9.70 tons per hectare and the lowest one was allocated to line No. 16 with 8.30 tons per hectare .The investigation of the correlation table of tested traits showed that the correlation coefficient of grain yield with plant height showed no significant effect and was reversed. However, the correlation coefficient of the plant heights with leaf length with the negative effect was significant at one percent probability level (r= -0.569). The obtained results of cluster analysis chart of the tested lines and quantitative traits studied in this research indicate significant difference between the tested treatments.