Crop Production
Year:2009 | Volume:2 | Issue:1|Papers Count:9

Breeding and release of high yielding and drought tolerant varieties along with advance agronomic practices are effective ways to manage drought and water deficit in agriculture. This experiment was conducted in order to identify tolerant genotypes to drought and evaluation of main characters and drought resistance indices on 20 bread wheat genotypes (18 promising  lines and 2 checks, Sardari and Azar-2) during three cropping seasons (2002-2005) in two locations, Kermanshah province, Sararood station (moderate cold area) and Maragheh, Maragheh station (cold area). The genotypes were evaluated in a RCBD design fashion with four replications. Simple and combined analyses of variance for three years were carried out. The results showed significant differences among genotypes in different irrigation application. The highest grain yield, yield stability, and drought tolerance were belonged to the genotypes nos.1 (14 Gene Bank Material), 2 (914 Gene Bank Material), 4 (F9.10/May"s"//Sabalan), 19 (Sardari), 20 (Azar-2), 3 (Turkey 13//F9.10/Maya"s") and 14 (Fengkang15/Sefid), under different irrigation scheme. Evaluation of stress tolerance indices i.e. stress tolerance index (STI), geometric mean productivity (GMP) and Mean productivity (MP) also showed the superiority of the above mentioned genotypes. Evaluation of different stress tolerance indices indicated that STI is a general index which can be used as selection criteria in breeding programs.

In order to examination of dual purpose herbicides on some wheat physiological indexes in different stages of phenology of this corp, an experiment was conducted in 1386-1387, in kordkoy, Golestan province with dry farming condition. This study was performed as factorial in randomized complete block design with 2 factors and 4 replications. The first factor included the type of herbicides: Shovalee (iodosulfuron plus mesosulfuron), Apyrous (Sulfosulfuron), Topik plus Granstar (Tribenuron methyl plus Clodinafop propargyl), Atlantis (idosulfuron plus mesosulfuron plus Surfactant) and Total (Metsulfuron methyl plus Sulfosulfuron) and the second factor was different stages of wheat phenology on the base of Zadoks division, that is: 2-3 leaf stages, tillering, flowering and physiological ripening of wheat. The results showed that tested herbicides had undesirable effect on seed yield, height and dry weight of wheat in some stages of phenology, and sometimes led to leaf burning. Average comparison of the herbicide type and the stages of wheat  phenology, and interaction of these two factors in evaluation of seed yield showed that Shovalee, Apiruos, Topic+Granstar, Atlantis and Total herbicides decreased yield seed in 2-3 leaf stages of wheat, which the most decreasing effect was related to Shovalee that had a significant difference with other herbicides. Examination the height of wheat shrub showed that Shovalee had the most decreasing effect on this characteristic, in 2-3 leaf stages. Calculating the correlation coefficient of tested characteristics indicated that seed yield had a positive and significant correlation with dry weight, in fourth week after poisoning, and with the number of tillering, height of shrub, weight of 1000 grain weight, the number of seed in each spike, the length of spike in 1 and 5% level, and showed the most correlation coefficient with height.

In order to evaluate the interference effect natural population weeds and plant density, an experiment with Randomized Complete Block design in factorial arrangement with 4 replications was conducted in 2006 in a field experiment at Ramin Agricultural and Natural Resources University, Khouzestan. Treatments included two factor, plant density of corn at three levels (4, 7 and 10 plants m-2) and weed interference at three levels (no interference as pure stands, interference to v9 and interference to v13). Results indicated that at optimum plant density (7 plants m-2), corn can by competitiveness increase own weeds interference decreased. Never less weeds caused of corn dry matter accumulation, crop growth rate, leaf area index, grain yield, grain number per ear and row number per ear decreased. Meanwhile weeds interfere caused to least of dry matter accumulation, crop growth rate, leaf area index and grain yield got from the treatments weeds competition to v13 in any of corn densities. In addition, in these experiments characterized that with corn density increasing on weeds infested treatments, corn tolerated weeds with yield loss till v9 stage (approximately 5-15% and 40 days after planting), while corn yield decreased with increasing duration of weed interference to v13 stage and harvesting (full season weed infestation), and decreased with increasing duration of weed control (pure stands).

In order to investigate of quality and quantity yield and growing degree day (GDD) of Plantago ovata and P. psyllium related to water stress and density, two experiments were conducted at the Agriculture research field, Tehran University, Karaj, in April 2005 and 2006. The experiments were designed in factorial experiments based in randomized completely block (RCB) with three replication in which The treatments were three levels of plant density (low, medium and high density), three water stress level (severe stress, medium stress and control) and two plantago species. Combined analysis results showed that water stress significantly decreased seed and biological yield. Average and high density in both species significantly need fewer GDD to get maximum dry matter. In Isabgul 850, 984 and 1120 GDD and in French psyllium 860, 982 and 1147 GDD need to be received 50% ripening in high, medium and control drought stress, respectively.

In order to study the influence of municipal waste compost and chemical fertilizer on yield and yield components in maize (Zea mays L.) an experiment was conducted at research farm of Sari Agricultural Sciences and Natural Resources University during 2007. The experiment was arranged in split plots based on complete randomized block design with two factors and three replications. Main plot included 6 fertilizer treatments (consisting of 20 and 40 Mg.ha-1 of municipal waste compost individually and enriched with 50% chemical fertilizer, chemical fertilizers and control). Sub plots were considered as one year or two year application of that fertilizer. Results showed that different rates of organic and chemical fertilizers had significant effect on yield parameters such as harvest index, row number, grain number per row and grain number per ear. Meanwhile, one year and two year application of these fertilizers caused significant differences on grain yield, total biomass and grain number per row. Interaction effects of two factors also were significant except for total biomass. According to results, the highest grain yield was belonged to two year application of 20 Mg.ha-1 municipal waste compost enriched with 50% chemical fertilizers but not significant with two year application of all fertilizer treatments and one year application of 20 Mg.ha-1 municipal waste compost enriched with 50% chemical. Among traits, total biomass had higher correlation with grain yield. Generally, it seems that using of municipal waste compost could improve maize performance in addition to reduction of environmental pollution.

Currently deficiency of raw materials and initiative resources caused an increasing need of cellulose industries to new lingo cellulose products and resources. kenaf as a fibrous plant is considered along with the other plant sources that their bast has suitable fiber. This experiment was carried out in split–plot form with 4 replication in order to evaluation effect of harvest time and genotype on hemp production in Research Farm of Gorgan University of Agriculture Sciences and Natural Resources in 2007. Experiment factors were six genotypes consisting of cubana, Neiger, 9277, Cubana 2032 and 7551, and three harvest times consisting of  85, 105  and 135 days after swing. Result showed that yield, bast, pith, and stem yield were affected by harvest time. Bast to pith in second harvest time and leaf to stem in first harvest time was more than the other times. In addition, interaction between genotype and harvest time was not significant. Genotype Neiger was the best genotype for yield, bast, pith and leaf yield also Cubana 2032 and Cubana with 40.41 and 40.00 percent were the best genotypes for bast to pith ratio. Third harvest time was the best for most factors except leaf to stem ratio results of this study showed that increase in length of period of growing could be result in more production of fiber in kenaf.

In order to study the effects of plant density and nitrogen rates on yield, nitrate and protein of silage maize (KSC 704) in Shahrekord area, an experiment was conducted during 2007 growing season at the Agricultural Research Farm of Shahrekord University. The experimental design of the experiment was randomized complete blocks with factorial arrangement with four replications. Treatment consisted of four levels of plant density (92600, 104200, 119000 and 138900 plants ha-1) and nitrogen rates (200, 240, 280 and 320 kg ha-1) were conducted. The results showed that increase in plant density led to a significant decrease in single plant yield and protein of grain. But, fresh forage and protein yield were significantly increased with increasing plant density. Increase in nitrogen rate resulted in a significant increase in protein of plant shoot and protein yield. Stalk NO3 was not significantly different among plant density and N treatments. Plant density x nitrogen rate interactions were not observed for all traits in this study. The maximum dry matter was obtained with 320 kg N ha-1, but it had no significant difference with 240 and 280 kg N ha-1 levels of N fertilization. The results indicated that, planting of silage maize with at least 138900 plants ha-1 and 240 kg N ha-1 might be appropriate for optimum production under conditions similar to this experiment.

 In order to determine the effect of vernalization on phenology and development rate of canola varieties, an experiment was conducted at research farm of Gorgan University of Agricultural Science and Natural Resources during 2005-2006. The experiment was a randomized complete block design arranged in split plot with four replications. Six varieties of canola (Option500, RGS003, Hyola308, Hyola60, Hyola420 and Hyola401) were as main-plots, and six vernalization periods (0, 10, 20, 30, 40 and 50 days) were as sub-plots. The results showed that increase in the duration of vernalization from 0 to 50 days, caused decrease in the number of days to development stages (beginning of green and yellow bud, and beginning and end of flowering), and caused increase in development rate. The response of all varieties to vernalization was quantitative, indicating that no-vernalization treatment did not stop their flowering. The varieties could develop to the flowering with 85-94% of their maximum development speed. In Hyola308, the vernalization demand was 30 days, but, in other varieties, that was 50 days. A simple vernalization model was produced according to the result of this study, which could be used in simulation models of canola phenologic development.

In order to study effect of seed weight on germination and growth of wheat seedling, an experiment in seed technology laboratory of Aboureihan paradise university of Tehran in 2005 has been done. In this experiment, at first stage, the seeds separated by longitude step, latitude step and set frequency parameters of gravity separator set. In second stage, 10 treatments of 1000 seed weight entered in standard germination test and seedling growth test in CRD design in 4 replications. In this experiment, in standard germination test traits of seed germination percentage, germination rate and mean of germination time and in seedling growth test traits of seedling length and dry weight of seedlings have been measured. The results showed that in standard germination test 1000 seed weight had not any significant difference on germination percentage, germination rate and mean of germination time. In seedling growth test, 1000 seed weight had significant difference on seedling lengths and dry weight of seedling. Also, comparison of means showed that in dry weight of seedling trait, maximum amount (0.02g) related to maximum of 1000 seed weight and minimum amount (0.016g) related to minimum of 1000 seed weight.