Crop Production
Year:2008 | Volume:1 | Issue:1|Papers Count:7

Damping-off is an important disease of safflower in Iran, that caused by Pythium ultimum. Because of its importance, fungi isolates were sampled from infected plants grown in research farm of the College of Agriculture, Gorgan University of Agricultural Sciences and Natural Resources, in 2006. Also it has been proved that the disease caused by Pythium ultimum. Evaluation of seventeen safflower genotypes (Zarghan-259, Arak-2811, Isfahan, Syrian, Dinger, Hartman, Aceteria, CW-74, LRV-55-295, LRV-51-51, IUTM12, PI-250537, IL-111, 34062, 34074, 34040 and 541-5) for their response to causal agent were performed in 2007. The experiment was conducted in paper towel environment was done as split plot design in a complete randomized blocks in which two environments (sterile and infected) were included as main plot and also seventeen genotypes were as sub plot in four replicates. Artificial inoculation was conducted with 105 per mL oospore suspension of fungi agent. In sterile media percent and speed of seed germination and also dry weight of seedling and in infected media percent, real percent and speed of germination, number of infected seedlings and number of non-germinated seeds was recorded. Results showed that there was significant difference among the genotypes for all evaluated traits and also for reaction to disease. Comparison of means indicated that genotype Dinger with 79.7% had the highest real germination in infected media, and genotypes 34062 and Isfahan with 24.4 and 14.2 % were in the next rank in this regard, respectively. The lowest diseased seedling in infected media were belonged to IL-111 (6.3 seedlings), 34062 (6.8 seedlings) and Dinger (8.3 seedlings), respectively. Overall, the results of this study showed that some of non-Iranian genotypes were a good source for resistance to damping-off. Additionally, some of Iranian genotypes in respect to seed germination and related parameters were weak, however for resistance to the disease were superior to others. So, genotypes Dinger, Isfahan and 34062 could be used in breeding program of safflower to produce cultivars with resistance to damping-off.

Seed dormancy is one of the major problems in the study of the effects of different factors on the weed seed germination characteristics because healthy seeds without dormancy, having high vigor and germinability are needed in these studies. This experiment was carried out to find simple, applicable, cheap, quick and efficient methods to breaking seed dormancy in velvetleaf which is one of the most important weeds in Iran. Two seed populations gathered from two locations in Golestan province were used in this study. Experiments were conducted in a completely randomized design as a factorial with four replications. Each seed population was divided to three parts; the first part (control) was stored in room conditions. The second and the third parts were placed in prechilling conditions (in a cool (40C) and wet place) for two weeks and three months, respectively. Then, nine mechanical and chemical scarification treatments were applied on each of these 3 seed parts. Treated seeds transported to petri dishes 15 cm in diameter. Germinated seeds were counted daily to calculate germination percentage, rate and uniformity. In addition, time trends of water absorption in different treatments were investigated. Combined analysis of variance results indicated that the population (location) has no significant effect, and prechilling and scarification treatments and their interactions have significant effects on germination components. According to results, the most effective treatments in non-prechilling and 2 weeks prechilling were soaking in boiling water for 5 and 10 seconds followed by soaking in sulfuric acid for 20 minutes, respectively. Based on obtained results, in prechilling for 3 months none of the chemical and mechanical treatments have acceptable germination. Germination percentages were 52, 50.5 and 53 percentages (in non-prechilled seeds) and 58, 63.25 and 63.5% (in 2 weeks prechilled seeds) in soaking in acid for 20 minutes, and soaking in boiling water for 5 and 10 seconds treatments, respectively. In the prechilling for 3 months, germination percentages of these treatments decreased to 12, 19.25 and 19.2%.

Water logging stress is one of the most important factors which affect wheat production particularly in western regions of Golestan province. This experiment was carried out in order to evaluate of six genotypes (N-81-18, Arta, Moghan, N-80-19, URWYT-82-11 and URWYT-82-17) of bread wheat in water logging condition at 2006-2007 growing season in Gorgan Agricultural Research Station. The experimental design was strip- plot whit five replications. The common traits such as biological yield, grain yield, harvest index, plant height, length of peduncle, and spike NO per m2, length of spike, spike weight, NO spike let per spike, NO of grain per spike, and grain weight were measured. Results of ANOVA in two conditions (with water logging stress and with out water logging stress) showed all traits have significant different (P<%1) except of length of spike and NO spikelet per spike. Also genotypes of experiment had significant different (P<%1) for traits of height plant, length of peduncle, NO of spike per m2, spike weight, NO of grain per spike, grain weigh per spike and grain weight. Moghan cultivar had highest grain yield, harvest index, plant height, and spike weight, NO of spikelet per spike and NO of grain per spike.

Germination response to temperature is different among plant seeds. Germination rate and percentage is maximal at optimum temperature (s), and then reach to zero at base and ceiling temperatures. The objective of this research was (1) to evaluate germination response of snail medic seeds to temperature and (2) to determine cardinal temperatures of germination rate and percentage. Therefore, seeds germinated at 10 to 400C by 50C interval. Results indicated that response of germination percentage and rate adequately described with dent-like and segmented functions, continually. Base and ceiling temperatures were obtained 0.46 and about 40°C for both germination rate and percentage. Optimum temperatures were 15-27.730C for germination percentage and 22.220C for germination rate.

This study was conducted to investigate the genotype´environment interaction effects on yield and yield components of wheat. Ten cultivars of wheat were evaluated in 8 environments (combinations of two levels of nitrogen and four irrigation regimes) in growing season of 2006-2007 at the Research Farm of Isfahan University of Technology. Based on the stability parameters of Eberhart and Russel, Pishtaz and Moghan1 that had higher yield than the average and regression coefficient of 1 (approximately), were more adapted cultivars. However, Khazar and Alvand cultivars showed specific adaptation to better and Falat, Darab and Roshan cultivars to poor environments. Path analysis of genotype´environment interaction (Tai's method) showed v1 component that indicated the correlation of fertile panicles/m2 with grain yield, was high and significant only for unstable cultivars, therefore, this component is not a suitable criterion for selection of stability. The environmental components showed that fertility and grain filling periods were the most sensitive growth stages of cultivars to the environmental conditions, therefore, it seems that selection for stability based on this component (v2) may not be effective. Genotypic component of v3 (seed weight) was the most effective component of yield stability and based on this component, Pishtaz was the highest yielding and stable cultivar. In general, according to the results of this study, Pishtaz with grain yields of 9.27 t/ha and with the highest stability was determined as the suitable cultivar.

Lead to continuing effects for increasing extensive of yield by means of advanced agronomic operations and selection of high yielding resistant genotypes. Therefore, due to evaluation and determination of best effective traits in improvement of yield and grain quality of local populations of winter wheat, an experiment was carried out in Uremia Agricultural Research station, on 30 local populations of winter wheat that were collected from different cool place. Population was planted in complete randomized block design with three replications. The under study traits were, plant height, grain weight of basis plant, Biomass weight of whole plot, grain yield of whole plot, harvest index, length of spike, Number of kernel per spike, thousand kernel weight and weight of spike. The results of correlation analysis were showed that traits had positive correlation. The results of analysis of variance were showed that, there were high significant differences among traits. Too between agronomic nitrogen efficiency of grain weight of basis plant, length of spike, thousand kernel weights, and grain yield of whole plot. Harvest index and number of kernel per spike had positive correlation. The results of comparison of mean's traits were showed that populations of 80, 83, 32 had high rate for purposes of harvest index. Also, the results of comparison of mean's traits were showed that populations of Shahriyar and Zarin purpose of biomass weight of whole plot and populations of Shahriyar and Zarin had high rate for purposes of grain yield and also, populations of triticale, 85, 42 for purposes plant height showed for consumer fertilizer nitrogen. Also, the results of comparison of mean's traits were showed that population of Alvand, Shahriyar and triticaleh had high number of kernel per spike. Also populations Shahriyar, triticaleh Alvand and zarin high rate for lengh of spike for between population temperate region had special for its. Thousands kernel weight populations Alamot and Zarrin high rate to answer for has used fertilizer nitrogen. Also population Zarrin, Shariyar and triticaleh high weights of spike basis plant had. Agronomic nitrogen efficiency population Zarrin, Shahriyar had high rate.  

In order to study the effect of sowing date and plant density on ear of sweet corn an experiment was conducted in Gorgan Reaserch station since June 2001 during 3 years. In this experiment five sowing date (24th June, 9th July, 24th July, 18th Agust and 23th Agust) and four plant density (45000, 55000, 65000 and 75000 plant per hectar) were evaluated in form of factorial experiment (5×4) within randomized comelet block design. Results indicated that ear length, plant hight, can seed weight, grain/ear ratio and harvest index was under the influence of year and maximum ear weight obtained amount 12810 kg/ha in theirty year. With delay sowing date until 9th July amount of ear weight was fixed but amount of it in July was smaller than June. Although with delay sowing date in July ear weight was fixed and maximum ear weight achived amount 13690kg/ha in 24th June. Stistically there wasn’t any different between plant density for ear weight and can seed weight but with increase plant density ear length and grain/ear ratio decreased. So for obtain maximum yield and marketable 45000-55000 plant/ha for sweet corn in summer sowing can be recommended.