نشریه پژوهشهای زراعی ایران
سال دهم شماره 4 (پیاپی 28، زمستان 1391)

One of the main constraints in predicting a crop yield mostly under rainfed conditions is the final yield temporal and spatial variability. This is mainly due to considering a constant value for a parameter within a model while in reality it usually changes at both time and location. In this study we used the Markov Chain Monte Carlo (MCMC) approach together with a simple crop model for chickpea yield prediction under both rainfed and irrigated conditions to see if there is any possibility to simulate the chickpea production when there are sparse and not enough available data. The crop model was run for the great Khorasan province and simulation results were compared with historical observed crop yield data (21 years) obtained by Ministry of Agriculture and various field experiments on chickpea within Khorasan. For model results verification Root Mean Square Difference (RMSD) was employed. Model results were acceptable at both irrigated and rainfed conditions which in turn indicated the high capability of the very simple crop model when linked with MCMC technique. Such a package would be able to analyze the chickpea production throughout the Khorasan chickpea production systems.

Ranunculus ficaria is an invasive perennial and tuberous root weed. Tubers are the most important reproduction and dispersion means for this weed. In order to study Cardinal Temperature and effect of fluctuation temperature on Germination of Lesser ceandine tuberous root two separated experiments were conducted at Weed Science Laboratory of Faculty of Agriculture Ferdowsi University of Mashhad in 2008. The experiments were a completely randomized design with four replications، In first experiment، temperatures included 1، 5، 10، 15، 20 and 25 ◦C for cardinal temperature. In second experiment fluctuation temperature، included 5/10، 7/12، 10/15 and 15/25 ◦C (13 H night/11 H day). Results indicated that optimum temperature was different for big and small tuberous roots. But between base and maximum temperature were not difference. Base and maximum temperatures were about 0 ◦C and 25◦C for both big and small tuberous roots. The optimum temperature for big tubers and small tubers were 8◦C and 14◦C، respectively. The result of fluctuation temperature showed that the highest germination occurred in low temperatures. Percent and rate of germination were highest at fluctuation temperatures of 5/10، 7/12 ◦C.

In order to study the effects of manure and biofertilizers application that were applied on parent plants، on the germination and emergence indices of produced seeds of fennel، two laboratory and greenhouse experiments based on completely randomized design with four replications were conducted in Ferdowsi University of Mashhad، Iran. Treatments were consisted of 11 different seed types that were produced on parent plants fed by: Compost (C)، Vermicompost (V)، Azotobacter (A)، Pseudomonas (P)، A+C، C+P، C+V، P+A، P+V، V+A and Control. Results of greenhouse study revealed that most studied treatments were effective on the height of fennel. Moreover، V and C+P treatments were superior in terms of emergence percentage and aerial dry weight، respectively. Results of laboratory experiment showed that C+V treatment were superior to other treatments in terms of germination percentage، germination rate، germination index and mean germination time. Overall، the experimental findings revealed that seed producing by manure and biofertilizers utilization on parent plants is a suitable method for production of organic seeds that have optimal germination and early seedling growth indices.

This study was carried out to evaluate the genetic diversity of the breeding lines isolated from the sesame landraces. Seventy genotypes were evaluated in randomized complete block design with two replications in 2008. The results showed that there were significant differences among the genotypes for all of the studied traits such as days to maturity، plant height and seed yield. There was no difference between the phenotypic and genetic coefficients of variations for most of the traits، thus it was concluded that the majority of their observed variations was due to the genetic factors. The grain yield of the genotypes ranged from 1089 to 4650 kg/ha. One of the breeding line isolated from Birjand landrace had the highest mean of days to maturity (170 days) and Yekta genotype had the lowest mean for this trait (118 days). The range of plant height among genotypes was 123 to 179 cm and the mean of capsule per plant was ranged from 46 to 181. Branches per plant had the highest broad-sense heritability (81. 1 %) and the estimated broad-sense heritability for grain yield was 75. 5%. Cluster analysis classified the genotypes in three distinct groups and there were significant differences among these groups for all of the traits، except days to maturity. Genotypes classified in the second group had the most capsule per plant and grain yield and they can be used for genetic improvement of this trait. Meanwhile genotypes of the first group can be used for genetic improvement of plant height and branches per plant.

Seed yield of the crops is a quantitatively inheritated trait and much affected by environemtal conditions; therefore، selection for genetic improvement of seed yield may have low efficiency because of the environment effectes. Selection indices can be more effective for simultaneous improvement of seed yield components and finally the seed yield. In order to investigate selection indices for seed yield improvement in sesame، 15 breeding lines along with five local populations of this crop were evaluated in a randomized complete block design with three replications at the research farm of Isfahan University of Technology in 2009. In this study، the traits of capsules/plant، seed weight، seeds/capsule، seed yield/plant and seed yield/plot were evaluated. The Smith-Hazel 1، Smith-Hazel 2 and Pesek-Baker indices were identified based on seed yield components of capsules/plant، seeds/capsule and seed weight. The results showed that seed yield was highly correlated with each of these indices and the estimated efficiency of indirect selection via these indices was relatively high. Thus، it seems that these selection indices can be effectively used for seed yield improvement. The estimated selection efficiency for improvement of seed yield/plot via selection for Pesek-Baker index was slightly more than that of Smith-Hazel ones. However، the efficiency of the Smith-Hazel indices for simultaneous improvement of capsules/plant، seeds/capsule and seed weight was a little higher than that of Pesek-Baker index

Cotton is one of the most important world crops and is considered as a major cash crop in the North East of Iran. All selections in plant breeding are based on diversity and an increase in genetic diversity determines the range of selection. In the present study، 24 cultivars of cotton available at the research station for cotton in the East of Iran -Kashmar- were studied using the ISSR marker. A total number of 13 primers، with repeated simple sequences، were used for the amplification of genomic DNA. Overall، 128 bands were obtained، 109 of which showed polymorphism. To evaluate genetic similarity between cultivars، cluster analysis accompanied by the similarity coefficient developed by Jaccard and Nee (1972)، were applied using the UPGMA method. Dendrogram analysis showed a high diversity in the cotton cultivars and two main groups with 70 percent genetic similarity dividing the cotton cultivars into two main groups; namely، tetraploid and diploid. The highest polymorphism percentage was related to 5'' (CT) 8RC3'' (100%) and the lowest belonged to 5'' (AG) 8YA3'' and 5'' (TC) 8G3'' (25%) primers. Based on the similarity matrix، the highest genetic similarity was found in Varamin and Khordad and the lowest in Avangard and Bakhtegan cultivars. Based on the obtained results، ISSR markers can be efficiently used for the investigation of genetic diversity among cotton cultivars.

In order to evaluate the effect of plant growth promoting rhizobacteria (PGPR) and phosphate solubilizing microorganism (PSM) on yield and yield components of wheat a pot experiment was conducted at Sari Agricultural Sciences and Natural Resources University during 2009. Experiment was arranged in factorial based on completely randomized design in three replicates. Treatments were included bio-fertilizer in four levels (non-inoculation control، Phosphate Barvare 2 (Pseudomonas fluorescens+Bacillus subtilis)، Supernitroplus (Azotobacter brasilense+Azospirillum lipoferum) and Nitroxine (Azospirillum + Pseudomona + Bacillus))، three levels of chemical nitrogen fertilizer (0، 75 and 150 kg urea/ha) and three levels of phosphorus fertilizer (0، 60 and 120 kg super phosphate triple/ha). Results showed that the studied treatments (biofertilizer، nitrogen and phosphate inorganic fertilizers) had significant effect on grain number per spike، 1000 grain weight، grain yield، straw yield، biological yield and harvest index. Interaction effect between biofertilizer and chemical fertilizers was significant in terms of grain yield. The maximum grain yield was resulted from simultaneously applying of Nitroxine and 75 kg ha-1 nitrogen fertilizer. By contrast، the highest straw yield was obtained when 150 kg nitrogen fertilizer was used. Grain yield had the maximum correlation with biological yield (r=0. 85**). Grain yield positively and significantly correlated with grain number per spike (r=0. 73**)، 1000 grain weight (r=0. 68**)، straw yield (r=0. 56**) and harvest index (r=0. 69**). In conclusion biofertilizer inoculations could reduce application of nitrogen and phosphorus chemical fertilizers and increase plant performance.

In order to evaluate the weeding time on yield and yield components of sesame، an experiment carried out in a split plot complete randomized blocks design with three replications in the Faculty of Agriculture، Ferdowsi University of Mashhad، in 2009. Treatments included sesame varieties (Kalat genotype and Oltan cultivar) as main plot، and weeding from the emergence up to 20، 30، 40، 55 and 70 days after emergence and weeding afterwards the 20، 30، 40، 55 and 70 days after emergence alongside the no weeding in whole growing season and also weeding in whole growing season as allocated as sub plots. The results showed that with increasing interfering period at the beginning or at the end of growing season، yield and yield components of sesame were decreased significantly (p≤ 0. 01). Therefore، grain yield increased in the longer periods of weeding. The number of capsules per plant was the most important yield component that had high correlation (r = 0. 70**) with the yield. Interference of weeds up to 30 and 40 days after emergence reduced yield in Kalat and Oltan respectively، though interference after that period reduced the yield of both genotypes.

In order to determine the effects of seed burial and flooding depths on the emergence and seedling growth of watergrass (Echinochloa oryzoides) and barnyardgrass (E. crus-galli)، this experiment was conducted in a covered free air condition، at the Rice Research Institute of Iran، Rasht in summer of 2009. The treatments included four seeding depths (0. 1 (seeds were mixed with the top soil)، 2، 4 and 6 cm)، and four flooding depths (0. 1 (saturated soil with no standing water)، 3، 6، and 9 cm) arranged as a factorial arrangement in a randomized complete block design with three replications. After 28 days، number of emergent seedlings، weed seedlings height، root and shoot fresh weight، leaf and root area were measured، and emergence percentage and root/shoot ratio were calculated. Since no germination of seeds was observed at the 6 cm sowing depth، this treatment wasn’t presented in results. Measured or calculated variable per unit was significantly different between two species and between various levels of seed burial and flooding depths. These variables also influenced by the interactions of the mentioned factors with an exception of emergence percentage. Emergence percentage and growth characteristics except for plant height were higher in E. oryzoides than E. crus-galli when weed seeds were located in the depth of 0. 1 centimeter. In seeds located in the depth of 2 centimeters، all variables were higher in E. oryzoides than E. crus-galli. In both species، the higher values for mentioned variables was observed in the saturated condition of soil، when weed seeds were located at the depth of 0. 1 centimeter and reduced with increasing flooding and seed burial depth. Results indicated that flooding condition with adequate height caused major limiting effects on emergence، establishment and growth of two Echinochloa species، especially when the seeds were deeply buried; but at decreased height specially saturated soils، emergence and growth of E. oryzoides were significantly more than E. crus-galli.

This research in order to study of tolerance ability of wheat cultivates yield and yield components to salinity of irrigation water at sensitive stages of growth، was carried out as a factorial based on a randomized complete block design with 3 replications at greenhouse of Agricultural Faculty of Bu-Ali Sina University، in 2009. Treatments were included wheat cultivars of Alvand، Tous، Sayson and Navid and salinity of irrigation water induced by sodium chloride at five levels of 0، 4، 8، 12 and 16 dS m-1. The results showed that percentage and rate of emergence، plant height، 1000-grain weight، number of seed per spike، number of spike per pot، biological and grain yield reduced by increasing salinity level. At all stress levels Navid cv. had highest emergence percentage. In non-stress and 4 dS m-1، Alvand cv. and at higher levels of stress، Tous cv. had high height in reproductive phase. At control and 4 dS m-1، Sayson cv. and at 8، 12 and 16 dS m-1، Tous cv. in majority of yield and yield components traits had significant superior than other cultivars. Tolerance index of Sayson cv. at 4 and 8 dS m-1 was more than other cultivars but at 12 and 16 dS m-1، maximum value of this index was belonged to Tous cv. At all salinity levels، Alvand cv. had least tolerance index to stress. Number of spike per pot had maximum direct effect on grain yield of wheat cultivars in stress condition. Also indirect effect of biological yield via number of spike per pot than other its indirect effects، had maximum share in wheat seed yield.

Salicylic acid is one of the phenol groups that play an important role in abiotic stress tolerance. This study evaluated germination characteristics of black seed (Nigella sativa L.) under six levels of priming with salicylic acid (0، 0. 1، 0. 5، 1، 2 and 4 mM) and five levels of water potential (0، -5، -10، -15 and -20 bar) using a 5×6 factorial experiment based on a completely randomized design with three replications. The results showed that the simple and interaction effects of water potential and salicylic acid were significant on germination percentage، radicle and plumule lengths، radicle and plumule weights، radicle/plumule dry weight ratio and consumed endosperm weight. With decreasing water potential، germination percentage، germination rate، radicle and plumule lengths، radicle and plumule weights and consumed endosperm weight of black seed were decreased and 50% germination time and mean germination time were increased. The highest and the lowest amounts of germination percentage were obtained in control and -20 bar by 81 and 15 percentage، respectively. Maximum amount of germination percentage، radicle and plumule lengths، radicle and plumule weights and consumed endosperm weight were achieved in 1 mM salicylic acid concentration. Also، the minimum of 50% germination time and mean germination time were observed in 1 mM salicylic acid concentration. In control، pretreatment with salicylic acid didn''t increase the germination characteristics of black seed، but in stress conditions it improved these traits. Therefore، it seems that pretreatment of black seed with salicylic acid could be improved germination characteristics in drought conditions and increase black seed drought resistance to water stress at germination stage.

The effect of drought stress on growth، photosynthesis، essential oil yield and chamazulene percentage of three chamomile (Matricaria recutita L.) cultivars in Islamic Azad University، Shoshtar Branch was studied. The experimental design was split-plot based on randomized complete blocke design (RCBD) with 4 replications. Main plots consisted of drought stress levels including control (90% field capacity)، medium stress (75% field capacity) and hard stress (55%field capacity) and sub-plots included 3 chamomile cultivars (Presov، Bodgold and Sherazi). Results showed that drought stress had significant effect on photosynthesis، plant height، organic solute concentration، flower yield، essential oil and chamazulene percentage of chamomile cultivars. Medium stress level did not impose significant effect on essential oil yield of chamomile cultivars compared to control. Under highest drought stress level، Presov and Bodgold cultivars had highest flower yield (123. 4 and 121 g/m2)، essential oil yield (0. 159 and 0. 163 g/m2) and chamazulene percentage (4. 81 and 5. 71).

To investigate the effect of different levels of nitrogen fertilizer and biofertilizers Azotobacter sp. and Azosprillum sp. on seed yield، oil yield and its percent and fatty acid composition in three sesame (Sesamum indicum L.) cultivars an experiment was conducted using splite plot factorial arrangement based on randomized complete block design with three replications at Agricultural and Natural Resources Reasearch Center of Yazd in 2009 cropping season. The treatments included: cultivars (Darab-14، Jiroft and Yazdi) assigned to main plots، nitrogen fertilizer (0، 25 and 50 kg ha-1) and biofertilizer (inoculation and no-inoculation) as factorial were randomized in sub-plots. Oil percent was measured using the Soxhlet method and fatty acid composition was measured using GC method. Results showed the significant differenc among three varieties concerning seed yield، oil yield and four fatty acids (oleic، linoleic، palmetic and stearis acid). Seed yield، oil yield، Oleic، Linolenic and Arasshidic acid significantly increased with applying N fertilizer. Seed yield، oil yield and linolenic acid percent significantly increased with applying biofertilizer. Oleic acid percent had negative and significant correlation with Linoleic acid (r = -0. 759**) and stearic acid (r=-0. 774**) percent. Generally، results showed the importance of applying biofertilizers against chemical fertilizers to protect the environment from harmful chemical pollution.

In searching for new strategies of medicinal plant production with high yield but without undesirable compounds or effects، it is important to investigate unconventional alternatives such as application of PGPR and cover crops cultivation. This experiment was conducted in a split plots arrangement with two factors based on randomized complete block design with three replications during years 2009-10، at Research Farm of Ferdowsi University of Mashhad. Cultivation and no cultivation of cover crops in autumn assigned to the main plots. The sub factor was biofertilizer application with four levels، included 1-Nitroxin (containing Azotobacter spp. and Azospirillum spp.)، 2-Biophosphorous (Bacillus sp. and Pseudomonas sp.)، 3-Nitroxin + Biophosphorous and 4-Control. During growing season plants were harvested by three cuts. Results showed that total shoots dry weight، leaves yield and LAI in plants under no cover crop cultivation had a significant advantage. Biofertilizers increased most characteristics e. g. fresh and dry total shoot yield، dry leaves and LAI. The interaction between fertilizer and cover crop was significant، as the highest yield of fresh shoots was observed in mix of nitroxin and biophosphorous with no cover crop، the highest and the lowest of leaf and green area index were obtained in plants treated by nitroxin without cover crop and biophosphorous with cover crop، respectively. Plants harvested in cut 3 had the lowest LAI and other two cuts had no significant difference concerning this trait. The highest and the lowest fresh and dry shoot yield were observed in cut 2 and 1، respectively. The most essential oil yield was in cut 2 and 3 (without significant difference) and cut 1 was the lowest. The results showed that the interaction between biofertilizers and no cover crop cultivation was significant، as use of the biofertilizers especially nitroxin and biophosphorous in no cover crop condition enhanced the most characteristics of basil in an ecological production system framework.

Salvia genus has 58 annual and perennial herbaceous species in Iran that 17 species are endemic and Salvia sahendica Boiss & Buhse is one of them. In order to investigate the effects of drought stress caused by PEG 6000 and salinity stress induced by NaCl on germination factors of Salvia sahendica، two experiments were carried out based on a completely randomized design with 3 replications. In the first experiment، the effects of drought levels (0 as control، -2، -4، -6، -8 and -10 bar) and in the second one، the effects of salinity levels (0 as control، 50، 100، 150، 200 and 250 mMol) on percentage and rate of germination، vigor index، radicle and plumule length were studied. According to the results، different levels of drought and salt stress had significant effects on all measured characteristics. In drought stress test، the highest and lowest percentage of germination was observed in -2 and -10 bar (respectively، 60. 11 and 41. 55 %) and highest vigor index was measured in -4 bar (62. 07). Study of salinity stress test showed that the highest and lowest percentage of germination was in 50 and 250 mM treatments (55. 61 and 12. 43 %، respectively) and highest vigor index was observed in control (54. 07). Radicle length was affected less than plumule length in these stress conditions. It seems that S. sahendica is well tolerance to drought and salt stress in germination stage.

In order to evaluate the effect of water stress and plant density on growth and seed yield of safflower، a study was conducted during 2009 growing season at Agricultural College of Shiraz University. The experimental design was split plot based on Randomized Complete Block Design with three replications. The treatments were deficit irrigation (100، 75، and 50% of field capacity-FC) as main plot and safflower density cultivar Sina in four levels (5، 10، 15 and 20 cm plant spacing) as sub plot. Results indicated that by increased plant spacing، seed yield decreased significantly. Maximum (351. 03 g m-2) and minimum (222. 95 gm-2) seed yields were recorded at 5 and 20 cm plant spacing، respectively. With reduction of irrigation from 75 to 50% FC، seed yield was significantly reduced up to 63% (from 368. 83 to 134. 10 g m-2). Among yield components، number of head seeds number per head and seed weight were significantly decreased. Plant height and seed oil percentage was also significantly reduced as a result of water stress and reduction of plant density. It is concluded the optimal safflower seed yield can be achieved by applying 75%FC deficit irrigation and 10 cm plant spacing that were (33 plant m-2).

In order to determine the effect of different levels of sulfur bentonite on yield and yield components of canola a factorial experiment was conducted on the basis of randomized complete block design with three replications in Mashhad in 2009-2010 growing season. Factors included four levels of sulfur bentonite (0، 300، 400 and 500 kg. h-1) and two varieties of canola (Modena and Zarfam). The result showed that the increase in sulfur increased some vegetative traits such as leaf area index and plant height. Using sulfur caused increased pod number، seed weight، in addition of oil and protein content and seed yield. Grain yield increase was due to seed weight and LAI. Two varieties were different to responses the sulfur. While in no sulfur application there was no significant difference in seed yield، in 500 Kg sulfur application yield of Zarfam compared to Modena increased about 29. 63. According to the results there are significant differences between cultivars in terms of response to the sulfur fertilizer. Therefore it is necessary to evaluate effect of sulfur application of canola productivity in different climate conditions of Iran.