Iranian Journal of Crop Sciences
Year:2008 | Volume:10 | Issue:1 (37)|Papers Count:8

In this study thirty three wheat cultivars were compared for osmoregulation capability using the ratio of projected pollen grains area under water stress to normal conditions. Digital images of pollen grains obtained from plants grown under well watered condition, were analyzed to obtain their projected areas. Field experimental arranged in a split-plot (cultivars were assigned to sub-plots and drought stress to main plots) in order to compare cultivars grain yield under water stressed and well watered conditions. Based on the results of pollen area ratio, cultivars were divided into two groups. Cultivars, Dez, Kavir, Roshan, Back Cross Roshan (winter type), Zarrin, Pishtaz, Omid and Alvand were classified as capable for osmoregulation as they had a ratio of higher than unit, while the others were grouped as incapable since had ratio lower than unit. Results of ANOVA showed that drought stress and cultivar had significant effects on grain yield and its components as well as biological yield and harvest index. In general, drought stress significantly reduced the grain yield. On the other hand, average grain yield of osmoregulation capable group was 1.73 times greater than that of incapable group. Meanwhile, significant correlation coefficient (r = 0.29**) was found between projected pollen area and grain yield under drought stress condition, implying that increased grain yield could be attributed to osmoregulation capability. Wheat cultivars grouped as capable for osmoregulation are suggested to be used in breeding programs for increasing drought tolerance.

In order to study the effect of sowing date and seeding rate on grain yield and yield components two rapeseed (Brassica napus L.) cultivars, a field experiment was carried out using a split plot factorial arrengements with three replications at the Zahak Agricultural Experimental Station, Zabol, Iran in two cropping seasons (2004-2006). Sowing dates were assigned to main plots at four levels (5 October, 20 October, 5 November and 20 November). Combination of two spring rapeseed cultivars (Hyloa401 and RGS003) with three seeding rates (6, 8 and 10 Kg/ha) were randomized in sub-plots. Results showed that sowing date had significant effect on grain yield and yield components (number of silique in plant, number of seed in silique, 1000 grain weight) and other studied traits.With delay in sowing date grain yield decreased 3.4 percent per week.The highest grain yield with mean of 3943 Kg/ha obtained in second sowing date (25 October ) and the lowest grain yield with mean of 1830 kg/ha in fourth sowing date (15 November).The effect of cultivar, except number of seed in silique, plant height and oil content, was not significant on the other components and traits. RGS003 cultivar with mean of 3249 Kg/ha performed better than Hyola401 with mean of 3062 Kg/ha. The effect of seeding rate, except on 1000 grain weight and plant height, was not significant on the other components and traits. Nevertheless, the highest grain yield with mean of 3282 Kg/ha was obtained from seeding rate of 10 Kg/ha. Interaction of sowing date × cultivar on number of silique in plant, interaction of seeding rate × cultivar on plant height and interaction of sowing date × seeding rate × cultivar on 1000 grain weight, were significant. It is concluded that sowing date of 20 October for RGS003 and Hyloa401 cultivars and seeding rate of 10 Kg/ha can be recommended for conditions of Sistan region.

In order to study the effect of corn and foxtail millet intercropping on grain yield and weed control, an experiment was conducted in a split plot arrangement in randomized complete block design with four replications at the Field Station of Tehran University in Karaj during 2006 cropping season. In this experiment maize (SC704) and foxtail millet (KFM4) was intercropped using additive pattern. In this study, the main plots were different dates of planting (planting foxtail millet 20 days before maize planting, planting foxtail millet 10 days before maize planting, planting maize and foxtail millet at the same date, planting foxtail millet 10 days after maize planting). Sub-plots were pure stand of two crops as well as three intercropping ratios (100% maize +12.5% foxtail millet, 100% maize + 25% foxtail millet, 100% maize + 50% foxtail millet). Intercropping of maize and foxtail millet controlled weeds and intercropping ratio of 100% maize + 50% foxtail millet had the lowest weeds density and biomass. The combination of 100% maize + 50% foxtail millet at the same planting date was the superior treatment, because of the highest Land Equivalent Ratio (1.435) and the highest grain yield. This was referred to better use of growth inputs and control of weeds biomass and density as compared to monoculture. Generally, intercropping 100% maize + 50% foxtail millet in the same planting date was of high grain yield, better use of growth resource and reducing of weeds density.

This experiment was carried out for evaluation of the effect of rate and time of nitrogen application on grain yield and yield components in spring safflower in Shirvan-Chardavol in Ilam during 2002-2005 cropping seasons. Experimental treatments were arranged as factorial in complete randomized block design with three replications. Nitrogen rates (50, 75, 100, 125 and 150 Kg.ha-1) and split application of nitrogen in three levels (first split: 50%: 50% ratio at pre-planting and late rosett, second split: 50%: 50% ratio at preplanting and early flowering and third split: one-third: one-third: one-third ratio at pre-planting, late rosett and early flowering). Combined analysis of variance indicated that interaction of nitrogen rate × split application was significant (p<0.05) on grain yield. Mean comparison showed that 100 Kg.ha-1 of nitrogen with triple splitting application at pre-planting, late rosett and early flowering stages produced higher grain yield (2752 Kg.ha-1). This was achieved due to increase in head/m2 (240 heads), grain/head (36.3 grains), and 1000 grain weight (34.4 g). Application of 100 kg.ha-1 nitrogen and its triple splitting produced the highest oil yield (755 Kg.ha-1).

This study was conducted at Moghan Agricultural Research Center in 2000-01 with five promising lines, two cultivars Chamran and Shiroodi as checks for yield, two cultivars Falat and Forontana as diseases checks. The main objective was to evaluate the promising lines for grain yield and diseases resistance in Moghan region. A randomized complete block design with three replications was used under two different irrigation conditions; furrow and sprinkler irrigations. Combined analysis of variance over two irrigation conditions showed significant effect of genotype at the 1% of probability level on plant height, number of tiller per plant, number of fertile tiller per plant, length of peduncle, grain weight per plant. Mean comparison of lines showed that no significant differences but lines N-81-8, N-81-9 and N-81-18 produced 6000, 6060 and 6310 Kg/ha, respectively. These lines lines were also resistance to yellow rust (O-MR) and fusarium head blight (O). Line N- 81-18 not only produced the highest grain yield but was highly resistance to yellow rust and fusarium head blight, under both furrow and sprinkler irrigation conditions. This line could be a promising candidate to be released in Warm Humid Caspian Zone. According to the results of this study sprinkler and furrow irrigations can be used for evaluation of new lines. In this study line N-81-18 with high grain yield and resistance to both yellow rust and fusarium head blight was designated as suitable candidate for Moghan region.

In order to determining the suitable planting date and planting density for new hybrid (Cms-26 ´ R-103) of sunflower, an experiment was conduct in Karaj, Iran in 2006 and 2007 cropping seasons, using split plot arrangement in a complete randomized block design with four replications. Two factors of planting date in four levels (9 May, 30 May, 20 June and 11 July) in main plots and plant density in four levels (6, 8, 10, 12 plant/m2) in subplots. The results showed that the effect of year on all traits was not significant. Planting date significantly affected all of measured traits except productivity index. The highest grain yield was achieved in the first planting date (i.e. 9 May) with 3540 kg/ha. The results also showed that the effect of plant density was significant on all traits (p<0.01), except 1000 grain weight and productivity index. Interaction of planting date ´ plant density was negligible on all studied traits except grain yield, total grain no. per m2 and number of filled grain /m2. The first planting date (i.e. 9 May) with 12 plants/m2 and the latest planting date (i.e. 11 July) with 6 plants/m2 produced the highest yield (4200 kg/ha) and the least grain yield (1430 kg/ha), respectively. The results revealed that planting dates from 9 May to 30 May with 12 plants per m2 were the most suitable combinations for obtaining the highest grain yield in sunflower new hybrid (CMS-26 ´ R-103).

In order to study the effect of biofertilizers on flowering, biological yield and root colonization in fennel (Foeniculum vulgare Mill.), an experiment was conducted in 2005 and 2006 growing seasons. The factors were mycorrhizal inoculation (inoculated and non-inoculated), phosphate biofertilizer (0, 30 , 60 Kg/ha) and vermicompost (0 , 5 , 10 Ton/ha). The treatments were arranged as factorial in a randomized complete blocks design with eighteen treatments and three replications. These treatments together with a chemical fertilizer control treatment (NPK: 90, 60 and 90 Kg/ha) were also evaluated using a randomized complete blocks design with nineteen treatments and three replications. Results showed that the highest umbrella no./plant, biological yield and root colonization percent were obtained with mycorrhiza treatment. Phosphate biofertilizer also showed significant effect on these traits. The maximum umbrella no./plant and root colonization percent were related to the plots with application of 60 Kg/ha of phosphate biofertilizer. The highest biological yield were obtained with application of 30 Kg/ha phosphate biofertilizer. The maximum umbrella no./plant and biological yield were obtained from vermicompost (10 ton/ha). The highest root colonization percent were also obtained with application of five ton/ha vermicompost. There were positive and synergistic interactions between factors. For example, intractions between mycorrhizal inoculation ´ vermicompost on biological yield. Differences between control and biofertilizer treatments were significant, as umbrella no./plant and biological yield in treatment of inoculation with mycorrhiza, application of 60 kg/ha phosphate biofertilizer and 10 ton/ha vermicompost were higher than control. Root colonization percent in treatment of inoculation with mycorrhiza, application of 60 Kg/ha phosphate biofertilizer and five ton/ha vermicompost was also greater than control.