فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 24 (زمستان 1391)

To investigate the effects of water deficit on some morphological characteristics and grain yieldof Armavirsky sunflower cultivar, an experiment in a randomized complete block design was conducted in Research Station of Islamic Azad University, Tabriz branch with three replications. Five levels of drought stress consisted: (D1=50, D2=100, D3=150, D4=200 and D5=250 mm evaporation from class A evaporation pan). Results showed that grain yields were 5486, 4480, 3080, 2460 and 2260 kg per hectare for D1 to D5 respectively. Increasing water deficit levels decreased grain yield, oil percentage, no. of grain per head, 100 seed weight, dry weight, stem diameter, head diameter, leaf area index, relative water content, chlorophyll content. While increased adaixial stomata number, percentage of empty seed and stomatal resistance. However, the differences between D1 and D2 were only significant for 100 grain weight, empty seed percentage, and no. of grain per head; It seems that these traits begin to increase after flowering; thus, if can be suggested that early irrigations of Armavirsky up to flowering may be carried out by D2 and then after by D1 levels to optimize seed yield and prevent significant decrease in other attributes.

To study the effect of cutting irrigation and application of biofertilizer and nitrogen on yield and yield components of corn single cross hybrid, an experiment was carried out in Satloo Agricultural and Natural resources Research Station of west Azarbaijan, 2009-2010. This experiment was arranged as split plot based on Randomized Complete Block Design with three replications.Four irrigation factors including I1, I2, I3 and I4, respectively: cutting irrigations at stem elongation, blossom and seed filling stages and normal irrigation assigned to main plots and fertilizer treatments consisted of Nitoxin + 50% urea (F1), Niragin + 50% urea (F2), and without biofertilizer application + 100% urea (F3) were allocated to sub plots.Results indicated that the effect of cutting irrigations had negative and significant effects on all characteristics; Fertilizer treatments on the other hand had significant effect only on seed numbers per ear, 100 seeds weight and seed yield. The highest seed yield was obtained under normal irrigation and treatment of Nitragin + 50% urea (12320.7 kg/ha and 11100.5 kg/ha) respectively.

Considering the importance of sweet corn as a new food product, this study was conducted to evaluate the effects of planting pattern on some important morphophiyziological characteristics and yield and yield components of sweet and super sweet corn (Zea Mays L. var. saccharata) varieties in Agricultural Research and Natural Resources of Khorasan Razavi Province, Mashhad, Iran in 2011. In this study three methods of planting (one and two raised bed and furrow planting) and three varieties sweet corn (Chase, Temptation, KSC403su) and one super sweet corn (Challenger) were studied in factorial experiment based on Randomized Complete Block Design with three replications. The result of ANOVA showed that sweet corn hybrids had significant differences in kernel depth, conservable grain yield and ear harvest index. It also showed that number of leaves per plant, number of leaves above ear, stem diameter, ear diameter, kernel depth, conservable grain yield and forage yield, were significantly different among three levels of planting patterns. The maximum main of these characters was belonging to two-raised bed planting pattern. In addition, the highest conservable grain yield was belonged to Challenger in two raised bed planting pattern with 25.76 ton/ha and highest fresh foliage yield was 48.6 ton/ha which belonged to Chase on one raised bed planting method. The highest ear harvest index belonged to Chase on two-raised bed planting pattern. Finally, the result showed that two raised bed planting pattern and Challenger with highest conservable grain yield trait could be used to increase sweet corn yield.

Surveying weeds of irrigated barley fields is one of the most important practices in weed management. Based on cultivated areas irrigated barley in all counties of Ardabil province during six years (2000-2005), 46 sample barley fields were selected and weed species were counted in each sampling point and population indices were calculated with Thomas method. By using specific furmula the density, frequency and uniformity of each weed species in fields were calculated. In each field longitude, latitude and altitude were recorded by using GPS. These data were used for producing weed maps using GIS. Results showed that Galium tricurnatum, Fumaria vaillantiand Raphanus raphanistrum were dominante broadleaf species in irrigated barley fields of Ardabil province. The dominant grassy weed species in these fields were Avena fatua and Secale cereal. Convolvulus arvensis and Cirsium arvense were the most important troublesome plants prior to harvesting in irrigated barley fields of this province.

To study the effects of different plant density on seed yield and yield components of three spring rapeseed cultivars a factorial experiment based on a Randomized Complete Block Design with three replications and 9 treatments was carried out during 2011 in Qazvin, Iran. Each plot consisted of 4 rows, 6 m long with 60 cm between rows. Seed were sown by hand (without pre planting irrigation) on February 2. Application of fertilizers, herbicides, pesticides and irrigation regime in this experiment were processed as they are usually done in the region. Three rapeseed cultivars Hayola401، RGS003 and Sarigol with three plant density levels (60, 80 and 100 plant/m2) were studied. At the end of growing period, traits like silique number per plant, seed number per silique and 1000 seed weight, seed yield and seed oil percent were measured. The results showed that plant density and cultivars affected silique number per plant, seed number per silique, 1000 seed weight and seed yield significantly. The effects of plant density by interaction on silique number per plant, seed number per silique and seed yield were also significant. Hayola401 produced the highest silique number per plant, seed number per silique, 1000 seed weight and seed yield. In these three cultivars under study the highest seed yield was obtained with the plant density of 80 plant/m2. Increasing plant density from 80 to 100 plants/m2 decreased silique number per plant, seed number per silique, 1000 seed weight and seed yield. This study showed that Hayola401 produced highest seed yield (1918/5 kg/ha) at plant density of 80 plant/m2.

To eveluate the effect of salicylic acid application under salinity stress conditions on physiologic and morphologic characteristics of artemisia, a factorial experiment based on Randomized Complete Block Design with four replications was conducted in Zanjan, Iran, during 2010-11. Treatments used were salinity four levels (0 (control), 4, 8 and 12 ds. m-1) and two levels salicylic acid (control and application of 0.5 mM). Traits measured were plant height, number of lateral shoot, seed yield of flowering shoots, antioxidant enzymes activity like catalas and superoxide dismutase, proline concentration and chlorophyll content of leaves were evaluated. The results showed that salinity stress decreased plant height, number of lateral shoot, seed yield of flowering shoots and chlorophyll content, and application of salicylic acid under both stress and non-stress conditions improved the above mentioned traits. Salinity stress also increased activity of antioxidant enzymes as well as catalase and superoxide dismotase and proline accumulation. Application of salicylic acid under both non-stress and salinity stress conditions decreased activity antioxidant enzymes and proline accumulation and reduced the effects salinity stress.

This research was conducted to evaluate the effects different concentrations of zinc sulfate applications at different growth stages on sweet corn at the Research Station of Faculty of Agriculture in Islamic Azad University, Tabriz branch in 2012. The study was conducted in split plot experiment based on Randomized Complete Block Design with three replications. Treatments were seven levels of zinc sulfate application (control, soil application, foliar application at 6-8 leaf growth stage, tasseling, grain filling stage, foliar application at three stages, soil application with foliar application at three stages) as main plot, three levels of foliar and soil application of zinc sulfate: (0.003, 0.005 and 0.007 for foliar application and 15, 25 and 35 kg/ha for soil application) as sub plot. Results showed that the highest grain yield correlated characters were obtained in foliar application at three stages and soil application with foliar application at three stages. In these conditions increasing of dry grain yield and ear were more than 50%. The higher values for grain production were obtained in Zn foliar application with 0.005 concentration (25 kg/ha soil application). Zinc sulfate increased Zn content of grains produced more than 100%. Thus, using Zn not only increases sweet corn grain and ear yield but also increased quality of products.

To investigate the effects of integrated mechanical and chemical weed management on barnyardgrass, smallflower umbrella and some rice agronomic characteristics an experiment was conducted in Rice Research Institute of Iran, Deputy of Mazandaran (Amol) during 2010 growing season. The experiment was performed in spilt-plot based Randomized Complete Block Design with three replications. Main plots consisted of three levels control (measures without weed control), one time and two times applications of cono-weeder and sub plots were seven herbicide applications (application of bentazon, bensulfuron-methyl, oxadiazone, butachlor, thiobencarb, hand weeding and control). The results indicated that the interaction of two mentioned factors did not have any significant effects on barnyardgrass and smallflower umbrella densities, but it had significant effect on weed total dry matter. The best method used to reduce weed total dry matter was hand weeding and two times application of cono-weeder without using herbicides. The highest grain yield was harvested in plots which treated by two times application of cono-weeder with or without herbicides applications, and hand weed control treatment.