نشریه یافته های نوین کشاورزی
سال سوم شماره 1 (پیاپی 9، پاییز 1387)

This experiment was conducted to evaluate the effects of sowing date on yield and its components of 8 sweet corn hybrids in Jiroft area in 2007 at Agricultural Research Center of Jiroft and Kahnouj, Iran. The design was laid out as a split plot design based on RCBD with three Replications. The main factor had two levels of sowing date (August 22ed, September 6th) and subplots were 8 hybrids (EXO8716636, Obsession, Harvest Gold, Chase, Temptation, Challenger, Basin and Power House). The result showed that highest economical yield (ear fresh weight at economical harvest) were obtained in August 22ed with 27.54 ton/ha and ear fresh yield was 24.05 ton/ha in September 6. The highest and lowest ear fresh yield were obtained about from cultivar Basin 30.73 ton/ha hybrid temptation 20.42 ton/ha respectively. Maximum ear fresh yield with 32.42 ton/ha and 31.87 ton/ha were obtained from hybrid Basin and Power house in planting date August 22. Finally, sweet corn cultivars, Harvest Gold, Power House and Basin with August 22ed are recommended for the Jiroft region.

In order to study of drought stress in different growth stages on yield and yield components of corn hybrid S.C. 704 in different plant density, this research was conducted in Ahvaz, during the summer 2008, in split-plot using RCBD with three replications. Water holding were applied in main plot in four levels (water holding at eight leaves stage, twelve leaves stage, tasseling growth stages and optimum irrigation was as the control). Plant density were as three sub plots in three levels (7.5, 8.5, 9.5 plant per square meter). Results showed that grain yield, biological yield and harvest index affected by water holding and plant population. Grain yield and harvest index was more affected in water holding in tasseling stage compare with other treatments. Maximum grain yield (890 gr/m2) was belonged to control water treatment with 75000 plant productions while minimum grain yield was obtained in tasseling stage with production 95000 plants with change in density of 75000 to 95000. Grain yield and harvest index decreased in response to plant population from 75000 to 95000 plants per hectare, while biological yield increased to plant density increment. In interaction treatment S4D2 yielded the highest grain yield (934 gr/m2) while the lowest grain yield was belonged to S3D3 with 152 gr/m2.

In order to investigate the effects of terminal drought stress on yield, yield components and assimilate remobilization in 8 wheat cultivars and lines for introducing of drought tolerance and susceptible ones, two experimental separated designs were occur using randomized complete blocks with three replications. A field study was conducted in 2009 in Agriculture and Natural Resources Experiment Station of Markazi province. The first experiment was water stress in post flowering stage and second experiment was irrigation with normal regime. The yield and yield components, plant height, day to flowering, harvest index and peduncle length were measured in this study. Response of cultivars and lines under optimum irrigation and water stress conditions were different. Water stress reduced most traits a well as yield and yield components. Results showed that some cultivars at water stress condition, showed tolerance and had relatively high yield For example, lines C-84-4 and C-82-12 showed high more tolerance under optimum and water stress, condition lines C-78-14 and Shariar cultivar showed high yield at optimum irrigation and lines C-81-14 and C-83-7 showed high yield at water stress condition. In order to evaluate stress indices among cultivars and lines we used 6 indices such as harmonic mean (Harm), stress tolerance index (STI), tolerance index (TOL), Mean productivity (MP), stress susceptibility index (SSI) and Geometric mean productivity (GMP). Results showed that all of these indices were the best, because there were the greatest correlations between yield and harvest index under water stress and optimum irrigation.

In order to comparison of the best seed vigor test for predicting of seedling emergence as well as their relationship with grain yield in rapeseed, a study was conducted using 9 rapeseed cultivars (Option500, Excell, PF7045.91, Peace, Cyclone, Quantum, Q2, Golliath and Hyola401). Laboratorial tests such as germination, seed deterioration and seedling growth tests were carried out using completely randomized design and field experiment as randomized complete blocks in Agricultural Science and Natural Resources at Gorgan University in 2004–2005. The results showed that germination velocity (germination test) had the highest relationship with seedling emergence in field and the equation estimated 84% of variation in prediction of seedling emergence using linear regression. The results obtained from variable option in the mode of stepwise procedure showed that only germination velocity at germination test had significant effect in prediction of seedling emergence in field. Thus this factor can be used for prediction of rapeseed seedling emergence in field. The results also showed that the correlation between seed vigor (rapid, uniformity and germination percentage) with grain yield was not significant when optimum plant density was present in the field.

This research was done in order to find the symbiotic mycorrhiza funguses and Azospirillum bacteria as biologic fertilizer in different levels of chemical fertilizers phosphor and nitrogen on yield and yield component of corn. Experiments were done in factorial design based on RCBD with three replications when soil control condition. The treatments were selected as using chemical phosphor and nitrogen fertilizer in 3 levels (without nitrogen and phosphorus fertilizers), (nitrogen 100 kg/ha and phosphor 50 kg/ha) and (nitrogen 200 kg/ha and phosphor 100 kg/ha). The Azospirillum treatments were settled in 2 levels (The usage and non usage) and Mycorrhiza treatments in 2 levels (The usage and non usage). The results showed that yield and yield component of corn was effected by fertilizers treatment so that the Azospirillum can significantly effect on grain yield and kernel numbers of the corn. It didn’t have any effect on 1000 kernel weight but Mycorrhiza could have a positive effect on grain yield and 1000 kernel weight (sig. 1%). It has no meaningful effect on the kernel number. Results showed that by using average of chemical fertilizers, microorganism activities increases but with increased consumption of chemical fertilizers microorganism activities were faint. In this research any negative affect and Antagonism between microorganism was not observed so that it can be used both microorganism until range of 100 kg/ha nitrogen fertilizer and 50 kg/ha phosphor fertilizer without any effect on each other.

In order to investigate the effect of drought stress on agriculturetraits in four safflower genotypes (Carthamus tinctorius L.), this experiment was conducted in field research station of Islamic Azad University of Arak, Iran during 2008-2009. The experimental design was split plot based on RCBD with four replications. The treatments composed of irrigation levels 100%, 75% and 50% crop water requirement as main plot and four safflower genotypes included Esfahan native, Esfahan-14, PI-537598 and IL-111 as sub plot. Results showed that drought stress reduced grain yield and oil yield. Grain yield reduced from 1198.2 Kgha-1 in irrigation equal 100% crop water requirement to 936.5 Kg/ha in irrigation equal 50% crop water requirement. The highest oil yield 407.2 Kg/ha was related to irrigation equal 100% crop water requirement and lowest oil yield 297.7 Kg/ha was found in irrigation equal 50% crop water requirement were obtained. Among genotypes, the highest magnitude of grain yield and oil yield were obtained from Esfahan native genotype. Interaction effects of drought stress and genotypes showed that highest grain and oil yield were obtained from treatment of 100% crop water requirement and Esfahan native genotype by 1583.05 kg/ha and 605.6 kg/ha respectively. The highest grain yield and oil yield were obtained in optimum condition and stress condition from Esfahan native genotype.

In order to study density of crucible and application of various levels of nitrogen on yield and yield components and some physiological characteristics of speed feed cultivar of forage sorghum, this research was done in the research farm of the Islamic Azad University of Arak, Iran in 2008. The experiment was conducted as a factorial design based on CRDB with four replications. Factors were selected as rates of nitrogen application in three levels (150, 250 and 350 kg/ha) and different planting densities (200, 300 and 400 thousands crucible/ha). Results showed that the effect of different nitrogen application levels on panicle height were significant (sig. %1). Also, interactions of traits on wet forage, number of tiller per pinnacle and dry to wet weight were significant. The highest yield of wet forage was 49.5 ton/ha in 400 thousands crucible/ha and 350 kg/ha nitrogen application when maximum level of factors were obtained.

In this study the yield and yield component ofCowpea and Tepary local beans germplasme in various plant densities were evaluated. Experiments were done in 2009 in research farm of Jiroft Islamic Azad University, Iran. The farm experiment was performed in form of split plot based on RCBD with four replications. The treatments were consist three plant density levels as the main factor and three tropical bean genotypes (The Jiroft local cowpea, the cream colour tepary bean mass and the black colour tepary bean mass) as sub factors. The various plant densities performed by regularization distance between plants on rows (5, 10,15 cm) after than plants complete establishment. Results indicated that the factor of change in plant density couldn’t affect the grain yield and the straw yield but the grain yield and the straw yield have significant difference at 1% and 5% statistical probability levels among the genotypes respectively. In this study the cream colour tepary bean with 2.1ton/ha and the black colour tepary bean with 1.37 ton/ha produced the highest and least grain yield respectively. The highest straw yield was related to cowpea genotype with 2.47 ton/ha and the least straw yield was related to black colour tepary bean with 1.71 ton/ha. also, the number of pod per plant, the number of grain per pod, the number of grain per plant were effected of planting density and were significant at 1%, 5% and 1% statistical probability level respectively. Different genotype of tropical bean from aspect traits of the number of pod per plant, the number of grain per pod, the number of grain per plant, the length of pod, the 1000 grain weight indicated significant effect at 1% probability level.