Iranian Journal of Crop Sciences
Year:2009 | Volume:11 | Issue:3 (43)|Papers Count:8

To evaluate grain yield and different agronomic traits in vetch (Vicia ervilia L.) genotypes, a field experiment was conducted using randomized complete block design, in Shirvan Dryland Agricultural Research Station, Northern Khorasan, and Iran, as spring planting in 2004, 2005 and 2006 cropping seasons. During the growing season, crop stand, days to 50% flowering, plant height, and days to maturity were recorded. At harvest, 100 grain weight, harvest index biologic yield and grain yield per plot were measured. Data of each season were analyzed separately and then on data for three seasons combined analysis of variance was performed. The effect of year on all traits was significant. The highest grain yield and biologic yield obtained in 2005. There were significant differences between the genotypes for all of traits, except crop stand. Genotype No. 10 with 1940 kg.ha-1 of biologic yield and 947 kg.ha-1 of grain yield and No. 11 with 1836 kg.ha-1 of biologic yield and 891 kg.ha-1 of grain yield performed better over three seasons. These genotypes were also earlier in days to 50% flowering; day to maturity and more desirable plant height.

To study the effect of drought stress, mycorrhiza and zinc rates on agro-physiologic characteristics of maize (cv. KSC 704), a field experiment was carried out in factorial arrangement using randomized complete block design with three replications at research field station of College of Agriculture and Natural Resources, Islamic Azad University, Arak, Iran, in 2006 and 2007 cropping seasons. The experimental factors included of three levels of irrigations: irrigation equal to crop water requirement (control), irrigation equal to 75% of crop water requirement and irrigation equal to 50% of crop water requirement, inoculation with mycorrhiza fungi (Glumus intraradices) at two levels: inoculation with and without, and zinc sulphate at three levels: 0 , 25 and 45 kg.ha-1. The results of combined analysis of variance showed that, drought stress significantly ffected water use efficiency, root dry weight, grain yield, biologic yield and harvest index. Drought stress reduced grain yield, biologic yield and harvest index but increased water use efficiency. Effect ofmycorrhiza was also significant on traits of root dry weight, percent of root colonization and biologic yield. Inoculation with mycorrhiza improved the concerend traits as compared to control. Application of 45 kg.ha-1 zinc sulfate significantly increased biologic yield, however, increases in grain yield was not significant. The highest root dry weight and percentage of root colonization was observed in 25 kg.ha-1 zinc sulfate. Inoculation with mycorrhiza improved concerned traits as compared to non- mycorrhiza not only in optimum irrigation level but also in drought stress conditions. Irrigation x mycorrhiza x zinc interactions on root dry weight, grain yield, biologic yield, harvest index and water use efficiency was significant. The highest grain yield was obtained from optimum irrigation (control) + no mycorrhiza + 45 kg.ha-1 zinc sulfate. It is concluded that with irrigation equal to 75% of water requirement + inoculation with mycorrhiza + 45 kg.ha-1 zinc sulfate obtain optimum yield.

Suitable seedbed preparation and adequate rate of seeding are necessary to obtain desirable plant population. These management practices are more important for plants with small seeds such as rapeseed. In this research, the effect of different tillage systems and seeding rates on machinery parameters, grain yield and yield components of rapeseed, cv. Orient, was studied in a split-split plot arrangement using randomized complete block design with three replications at the Kabutarabad Agricultural Research Station, Isfahan, Iran in 2003-2004 cropping season. Four primary tillage systems: moldboard plow to a depth of 20-25 cm, chisel to a depth of 15- 20 cm and 8-10 em and disk to a depth of 8-10 cm were assigned to main plots and two secondary tillage methods: disk and rotary tiller to a depth of 8-10 cm and three seeding rates; 4, 8 and 12 (kg.ha-1) were randomized sub-plots and sub-sub plots, respectively. Tillage methods showed no significant effect on mean weighed diameter of clods. Disk and rotary tiller had maximum and minimum machinery effective field capacity, respectively. By increasing seeding rate from 4 to 8 and then to 12 kg.ha-1, number of days from planting to the end of flowering and flowering duration decreased. Increases in seeding rate increased plant population. Using of 8 kg.ha-1 of seeds produced higher grain yield (2521 kg.ha-1) than 4 kg.ha-1 seeds (2400 kg.ha-1), but was not significantly different from 12 kg.ha-1 (2426 kg.ha-1). Based on these results, it might be concluded that disk harrow method as the secondary tillage with 8 kg.ha-1of seeds as desireable agronomic practices under conditions similar to this study. However, when rotary tiller is used, the seeding rate might decrease to less than 8 kg.ha-1.

To evaluate the effect of manures on the damping-off, Alternaria leaf spot (ALS), Verticillium wilt (VD), yield and yield components of cotton, a field experiment was carried out at Cotton Research Station of Kordkoy (35 kIn west of Gorgan,), Iran, with silty-loam soil and histories of soil-borne diseases including; seedling diseases (Rhizoctonia solani, Pythium ultimum, Fusarium spp.) and Verticillium dahliae, in 2004-06 growing seasons. Three sourc.es of manure (cow, sheep and poultry) and four manure levels (0, 10, 20 and 30 tons.ha-1) were arranged in a 3x4 factorial experiment using randomized complete block design with four replications. The results showed that the effect of source (S) and rate (R) of manures were significant on seedling emergence, length of 5th sympod, boll weight (BW), yield, VD and ALS, No. boll.plant -1, post-emergence damping-off, and ALS severity. The SxR interaction was significant on BW, No. boll.plant -1seedling emergence, yield and I diseases incidence. Application of poultry manure (PM) increased cotton yield and decreased damping-off and verticillium wilt diseases. Among animal manures sources and levels 20 tons. ha-1 of PM had the most seedling emergence and the least seedling diseases. However, the highest and lowest Alternaria leaf infection was scored in 10 tons.ha-1 of PM and 30 tons.ha-1 of cow manure (CM), respectively. The 30 tons.ha-1 of CM had also the lowest disease severity. The greatest verticillium wilt incidence and severity was scored in 30 tons. ha-1 of PM and the highest wilt infection and disease severity index were scored in 10 tons. ha-1 sheep manure (SM) and 10 tons.ha-1 of CM, respectively. In conclusion, application of poultry manure in the infected cotton field to the verticillium wilt improved agronomic performance and yield of cotton as well as reduced verticillium wilt incidence and severity.

To study the effect of application of plant growth promoting rhizobacteria (pGPR) including; Azotobacter chroococcum, Azospirillum lipoferum, Azospirillum brasilense and Pseudomonas fluorescens on phenology and grain yield of late maturity maize (Zea mays L.) hybrids (KSC700, KSC704 and a promising single cross, B73xK18), a field experiment was conducted in two successive cropping seasons. Exprimental treatments including seeds .of maize hybrids inoculated with single (one by one bacteria) and co-inoculated by two and three bacterial combined inoculants and no inoculation as control. Duration from planting to seedling ,fourth, eighth and tvelveth leat; tassel,ing pollen and silk emergence, pollen shedding termination, silk desiccation and grain physiologic maturity as well as vegetative growth period, pollination, silking, coincidence of flowering and grain filling periods were detrmined using Growing Degree Days (GDDs). Grain yield per hectare was also determined. Results revealed that PGPRs affected phenology of maize hybrids as leaf; tassel pollen and silk emergence was accelerated and duration of pollination, silking, coincidence of flowering and grain filling period was prolonged. Corrolation coefficients analysis revealed that GDD for developmental periods and phonological events were positively correlated. It was also revealed that application of inoculantion with combination of all bacteria inoculats had the highest promoting effect on phenology of maize hybrids, Co-inoculation of seeds by Azotobacter chroococcum and Pseudomonas fluorescens and inoculation of seed by each of them had also high promoting effect., respectively. Maize hybrids had differed in their phonological response to application of PGPR and KSC704 responded more vigorously than other hybrids, followed by B73 xK18 and KSC700, respectively. The highest grain yield obtained from KSC700 co-inoculated with all bacteria.

To study the effect of potassium fertilizer under different irrigation levels on grain yield and water use efficiency of two rapeseed (Brassica napus L.) and Indian mustard (Brassicajuncea L.) a field experiment was conducted in a factorial experiment using randomized complete block with three replications at Zahak field station, Agricultural and Natural Resources Research Center of Sistan in 2007-2008 cropping season. Three irrigation levels including (S1=irrigation after 50 percentage depletion of soil water (control), S2=irrigation after 70 percentage depletion of soil water and S3 =irrigation after 90 percentage depletion of soil water), two Brassica species (Hyola401 Hybrid and a landrace of Indian mustard) and three levels of potassium fertilizer (K0=0 , K1=150 and K2= 250 kg.ha-1 K2SO4) comprised the experimental factors. Results showed that the effects of irrigation levels, Brassica species and potassium fertilizer on grain yield, number of silique.plant-1, number of grain.silique-1, number of aborted silique. Plant-1, 1000 grain weight and water use efficiency was significant. Considering grain yield and water use efficiency Hyola401 performed better than Indian mustard landrace by 17% and 15%, respectively. Production efficiency of rapeseed was higher in this experimental condition. With increasing stress intensity, grain yield reduced and water use efficiency increased significantly. Grain yield in severe water stress treatment (S3) was 27% lower than the control (S1), however, water use efficiency increased by 16%. Increasing water use efficiency reduced water used in S2 and S3 treatments by 7% and 39% as compared with control (S1). With increasing potassium application rate, negative effect of water stress on grain yield was ameliorated and grain yield improved. Application of 250 kg.ha-1 of potassium increased grain yield and water use efficiency by 21% and 22%, respectively. Interaction of irrigation x potassium application was significant for grain yield, water use efficiency and number of aborted silique.planrl, but not for the other traits. The results also showed that in S3 treatment differences between lowest grain yield at K0 and highest grain yield at K2 was 779 kg.ha-1 which was 52% greater than the control. Results of this study showed that potassium application can positively affect grain yield and water use efficiency of rapeseed in severe and mild stress conditions. It is concluded that potassium application was effective on plant growth and formation of economic yield in conditions of Sistan region by ameliorating damages caused due to water stress.

To study the response of 180 genotypes of hexaploid wheat to terminal drought stress for grain yield and baking quality properties, a field experiment was conducted at reasearch field station of Seed and Plant Improvement Institute (SPII), Karaj, Iran in 2005-2006 cropping season. Genotypes were planted in two separated experiments simulating nonstress and stress (applied trom anthesis to physiologic maturity) conditions using an unreplicated systematic experimental design. FollowingIdentification and classification of genotypes in three groups: tolerant genotypes with reasonable yield potential (group A of Fernandez), genotypes with reasonable yield potential and susceptible to drought stress (group B of Fernandez) and moderately tolerant genotypes, genotypes of these three groups were evaluated for baking quality properties. Results of this experiments showed the theory of "improving bread quality properties of bread wheat under stress conditions" is only applicable to susceptible genotypes and to some extents to moderately tolerant genotypes, due mainly to increased grain protein content followed by reduction of 1000 grain weight in stress conditions. This theory is not relevant to drought tolerant genotypes, because in these genotypes no considerable change in proportion of protein content 10 carbohydrates was observed, under stress conditions. The results of this study suggested that identification and selection of genotypess with high grain yield and desirable baking quality properties under non- stress and stress conditions practicable. In this study 7 drought tolerant genotypes with good baking quality were identified in both non-stress and stress conditions. Although susceptible genotypes may gain better baking quality properties under stress conditions, but this is usually compensated by yield penalty.