مجله علوم گیاهان زراعی ایران
سال چهل و هفتم شماره 1 (بهار 1395)

This study was conducted to investigate the effects of different temperatures on seed germination of Plantago ovata and also to evaluate cardinal temperatures. Various constant temperatures (5, 10, 15, 20, 25, 30 and 35ºC) were conducted in a completely randomized design with four replications. The germinated seeds were counted every day and the rate of germination percentage, cumulative germination and cardinal temperatures of Plantago ovata seed germination based on two regression models including Intersected-lines Model and Quadratic Polynomial Model were calculated. The effects of temperatures on rate and percentage of germination was significant. The highest germination rates were in 20ºC (R50=0.067). Based on the two regression models, Intersected-lines Model and Quadratic Polynomial Model, the cardinal temperatures (Tbase, Topt and Tmax) of Plantago ovata seeds were: (3.9-4.5), (18.8-21.1) and (33.7-34.1)°C, respectively. With increasing temperature, the more suitable conditions in terms of temperature, is created for Plantago ovata seed germination and germination rate is increased.

This study was conducted to evaluate the effect of mandatory of self-fertilization on morphological and agronomic traits of orchad grass. Three populations including self-fertilization, open pollination and parental genotypes (each consisted of 25 genotype of orchad grass) were evaluated using a split plot experiment according to a randomized complete block design. Significant differences were found among populations for day to ear emergence, day to pollination, spread, fresh yield, dry matter yield, plant height, leaf to stem ratio and percentages of dry matter yield. For most of the traits, means of self-pollinated population was less than parents and open pollinated population. Forage yield of self-population was 44% less than parents indicating the probably of inbreeding depression. However, days to ear emergence and days to pollination in self population was higher than parental genotype. Negative correlation was found between forage yield with day to ear emergence and day to pollination. Biplot of principle component analysis clearly differentiate three populations confirmed by cluster analysis. In conclusion, the result showed that orchad grass has ability for self-fertilization and therefor it is possible to develop inbred line from this plant in future breeding programs.

In view of the importance of terpene in human’s life, analyzing the relationship between them and the involved genes are of crucial necessity. The necessity is for exploring influential genes. Among different plants containing terpene, Artemisia is included. In this study, several genes Farnesyl diphosphate synthase (fds), Hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (hdr) and Isopentenyl diphosphate isomerase (idi) in pathways 2-c-methyl-erythritol 4- phosphate (MEP) and Mevalonate (MVA) were analyzed in comparison to some monoterpene and sesquiterpene content in three tissues namely leaf, bud and flower of Artemisia diffusa. This study was conducted to compare RT-PCR data of genes with data from terpene GC-MS results. Results showed that it seemed for certain terpenes production in certain tissues, the above genes had limiting function (as idi in bud for 1,8- cineole and germacrene-D). These genes play important roles in terpene production and for some other terpenes, probably, other downstream genes such as terpene synthase had this limiting role (about beta-farnescene, for example, genes idi and fds had no limiting role in none of tissues mentioned above). Another point which casts doubt on fds, hdr and idi functions in terpene production is post-transcriptional regulation of these genes, the factor which was not evaluated in this study.

Terminal heat stress is the most widespread heat stress in the world. In order to evaluate the effect of heat stress on yield, yield component, and mopho-phenological traits of barley, 10 barley genotypes including the 2-row genotypes: Mahour, Khoram, Nimrooz, Abidar and 6-row genotypes: Yousef, Rihan 03, Izeh, Zahak, Nosrat, Jonoub were tested under normal (optimum sowing date) and heat stress (late sowing date) conditions in experimental field of Shahid Chamran University of Ahvaz. The experiment in each condition was arranged in a randomized complete block design. Terminal heat stress caused significant reduction in days from sowing to heading (38%), days from sowing to maturity (34%), plant height (47%), peduncle length (36%), biological yield (52%), spike length without awn (21%), number of spikelet per spike (31%), number of kernels per spike (36%), 1000 kernel weight (7%), harvest index (7%) and grain yield (42%). According to the results, in normal condition Yousef with 5.4 t/ha and in stress condition Rihan 03 and Jonoub with 3.4 t/ha have the maximum grain yield. Abider in both conditions showed the minimum yield. Based on the results, the maximum correlation coefficient was observed between harvest index and grain yield in both conditions, heat stress (r=0.77, p ≤0.01) and normal (r=0.91, p ≤0.01), suggesting the considerable role of this trait for evaluating the barley genotypes in heat stress experiments. 6-row barley genotype had superiority for most of traits in compare to 2-row genotypes and finally gave more grain yield in both conditions.

In order to study of water deficit effects on yield and some vegetative aspects of cotton, 30 cotton genotypes evaluated in 2014 summer at Garmsar Agricultural Research Station in greenhouse and field conditions. The experimental design was split plot based on a completely randomized blocks with three replications. Six superior genotypes including K8801, K8802, Avengard, Varamin, Khordad and Qum red boll selected for field experiment. Main plot was stress levels including control, mild and sever water deficit and subplots designated to genotypes. In greenhouse, the results showed that vegetative indices of genotypes significantly affected by water deficit stress. Based on the result of field experiment, vegetative traits, yield and yield components of genotypes were significantly different. In general, traits such as dry matter of root and shoot, number of root branches, crown diameter and chlorophyll content (spad value) had positive and significant correlation with yield in filed, so could be used in evaluation of cotton drought tolerance. Also, K8801 had higher yield than other genotypes in water deficit condition and could be introduced as a superior genotype for the region of study.

To study the effects of phosphate and zinc sulfate fertilizers application methods on the yield and yield components of maize under water stress a randomized complete block with split plot factorial arrangement with three replications at research farm of the Bu Ali Sina University was conducted in 2014. Three levels of irrigation after 60, 90 and 120 mm evaporation from evaporation A pan was assigned in main plot and two factors including phosphate fertilizer application methods (broadcasting and placement) and zinc sulfate (non, foliar and soil application) were assigned in sub plots. The results showed that with increasing water stress from 60 to 90 mm evaporation of pan grain yield decreased by 28 percent, but in condition of severe water stress, (irrigation after 120 mm evaporation), grain yield decreased by 54 percent. In no stress conditions, foliar application of zinc sulfate, compared to soil application and no application increased significantly the number of grains row per ear, biological yield, corn length and its diameter. According to the results phosphate placement treatment in sever water stress and no zinc sulfate application conditions caused a significant increase in the number of grain per row and 100 grains weight. In this study the highest harvest index was obtained in no water stress plus zinc sulfate foliar application (47.56%).

The Iranian Thymus daenensis subsp. daenensis is rich in monoterpene phenols (especially thymol and carvacrol). This research was conducted to isolate and characterize the plant growth promoting rhizobacteria (PGPRs) from rhizosphere of T. daenensis. PGPRs were screened based on some physiological traits including IAA production, phosphate solubilization, and siderophore compounds production abilities, and also seed germination and vigor tests. Twenty one rhizobacteria were isolated from the rhizosphere samples of T. daenensis which grow widely in Iran, and their effect on seed germination properties was studied in a completely randomized block design with three replications. We could characterize four isolates for PGPRs activity based on physiological and germination assays. TDE3, TDE16 and TDE20 isolates had the phosphate solubilization and siderophores production abilities. TDE4 (Achromobacter spiritinus) was the only isolated bacteria which significantly improved the SGR and VI of T. daenensis seeds. These four isolates have the potential to be used as PGPRs in cultivation of T. daenensis.

Fusarium head blight (FHB) disease caused by Fusarium graminearum is one of the most destructive diseases of wheat that in addition to the loss of product quality and quantity is able to produce the dangerous carcinogenic toxins in human and animals. In this study, the effects of different fertilizer treatments (Vermicompost, Chemical fertilizer and Mycorrhiza) on performance components and expression of several genes involved in disease resistance pathway was investigated. For this reason, Falat wheat cultivar was used in a completely randomized design with four repetitions in greenhouse conditions. The analysis of variance showed that the effects of different fertilizer treatments on 100-seed weight, plant height, weight per plant, seed performance, biological performance and the harvest index were significant at 1% probability level. The analysis of gene expression data showed that beta Glucanase and Oxalate Oxidase genes had a significant increase in all treatments but the highest increase was observed in vermicompost and chemical fertilizers mixture. The results indicated that the mix application of biologic and non-biologic fertilizers could be induce systemic acquire resistance in infected plants.

Salinity stress is one of the most important abiotic stresses which threaten plants. In order to study the effect of salinity stress on yield and yield components of sunflower and also genetic analysis of these traits in relation with salt tolerance, a factorial experiment based on a completely randomized design with three replications was conducted. Pots were arranged outside the greenhouse in an open air area under natural environmental conditions. The studied factors were 2 salinity stress levels (normal and 6 dS/m) and sunflower recombinant inbred lines (102 lines derived from the cross PAC2 ×RHA266 together with parental lines). Results showed the significant effect of salinity stress on all of studied traits except petiole length, leaf width, leaf length, head diameter and seed weight, meanwhile, the effect of genotype was significant on all of the studied traits. Genetic analysis of measured traits was done using a linkage map with 221 molecular markers (210SSR/11SNP) with an average distance of 7.44 cM between markers via composite interval mapping (CIM). 14 and 17 QTLs were detected for studied traits under normal and salt stress conditions, respectively. The maximum amount of R2 (39.7%) was detected for QTL identified for days to flowering in salinity stress conditions. The results showed the existence of co-localized QTLs for some of the studied traits under normal and salt stress conditions. Using co-localized QTLs improve the efficiency of marker-assisted selection in plant breeding programs.

To study the response of pinto-bean yield and yield components in intercropping with maize and naked-pumpkin under weed competition, two similar experiments were conducted in Rasht and Roudsar separately each in a randomized complete block design with 3 replications on factorial arrangements experiment in 2013. The treatments of first factor consisted of pinto bean (100 and 75%) sole cropping, maize – pinto bean (100-100 and 75-75%) double cropping and maize- pinto bean- naked pumpkin triple cropping (100-100-75 and 75-75-75%). The treatments of second factor include twice hand weeding and no weeding. The results showed that nine weed species were found in Rasht and six weed species were in Roudsar experimental stations. The broadleaf pigweed in Rousdsar and grassy weeds of Bermudagrass and hairy crabgrass were dominant in Rasht. In Roudsar area, the hand weeding treatments had outstanding role in weeds control, while, in Rasht experiments was not clear, due to presence of perennial weed. Double and triple cropping systems suppressed weeds more than sole cropping systems. In Roudsar, the highest number of pods per plant, number of grain per pod, 100 grain weight and grain yield of pinto bean were observed in sole cropping in hand weeding and the lowest amount of them were observed in sole cropping system in no weeding. In Rasht, the highest grain yield was observed in sole cropping with high planting density. Finally, double and triple cropping systems due to better weed control produced the highest yield and yield components in comparison with sole cropping systems in no weeding treatment.

The development of seminal and lateral root system plays a major role in plant access to water and nutrients under abiotic stress, especially salinity. In order to understand the relation between root growth responsesand shoot physiological indices oftwo bread wheat cultivars contrasting in salt tolerance (Kavir and Shiraz), a greenhouse experiment was conducted with two salinity levels (0 and 150 mM NaCl), growing in PVC tubes. Salinity decreases seminal root length, total root length, stomatal conductance, relative water content, chlorophyll index, shoot and root dry weight when compared to control. Although, the values for most traits in salt-tolerant cultivar were more, but seminal root length, total root length and relative water content were less than susceptible ones under salt stress. A significant correlation was observed between root growth characteristics and physiological responses under salt stress. Thus, given the similar effects of salinity on growth characteristics of roots and shoots, it seems that root growth responses can be used as a valuable index for screening salinity tolerance. Because, salinity is caused to reduce the plant's ability to absorb water, resulting in a rapid decline in growth rates associated with a series of physiological changes and finally leads to osmotic stress effects.

In order to study the effects of irrigation regimes, planting season and seed priming on grain yield and components of Hashem genotype of chickpea in Nurabad, northern Lorestan, two 3-replicate split-plot field experiments, one autumn- and the other spring-sown, were conducted. The primed and non-primed seeds (subplots) of this chickpea genotype were sown in autumn and spring and subjected to four irrigation levels (i.e. irrigation after 75, 100 and 150 mm evaporation from a Class-A Pan and no irrigation). Autumn-sown chickpea out-performed the spring-sown chickpea by 41.9, 7.4, 3.4, 32.5, 43.6, 62.9, and 13.7% in terms of pods/plant, plant height, 100-seed weight, seed weight/plant, dry matter and grain yield and harvest index, respectively. Irrigation after 75 (2296 kg/ha), 100 (2044 kg/ha) and 150 mm evaporation (1775 kg/ha) led to 75.4, 56.1 and 35.5% increases in grain yield, respectively, relative to the no irrigation condition (1309 kg/ha). Seed priming led to 8.5% increase in grain yield, averaged over planting seasons and irrigation levels. It could be concluded that while seed priming enhances grain yield, planting genotype Hashem in autumn along with irrigation after 75 mm evaporation may lead to notable increase in its grain yield in the northern regions of Lorestan.

Safflower is a crop native to Iran and could be improved in plant breeding programs by inter-specific crosses. This study was conducted to evaluate genotypes of safflower derived from interspecific hybridization for the relationships between some agronomic traits and yield components. The genotypes were planted according to a randomized complete block design with three replications at the research farm of Isfahan University of Technology in 2011. Seed yield per plant ranged from 41.6 to 49.14 gr. The hybrid genotype 4 (F6) had the highest mean of seed yield per plant. The results of the correlation analysis showed that 1000-seed weight and head diameter were the most correlated with the seed yield per plant. Stepwise regression results showed that the 1000-seed weight and head diameter were the most important factors determinants of grain yield per plant and justified 61 percent of yield variation. The path coefficients analysis also showed that, 1000-seed weight, head diameter and number of heads per plant were considered as the first order variables and accounted for 56% of total variation of yield. The results also indicated that both traits of 1000-seed weight and head diameter could be considered as selection criteria for increasing safflower yield in breeding programs.

The complexity of the genetic control of drought tolerance makes inevitable using of molecular methods with biometric approaches to its improvement in plants. Present study was conducted by 121 advanced lines and varieties of soybean under two moisture levels, normal and drought stress with 21 microsatellite markers linked to drought tolerance in two regions, namely, Rasht and Gonbad-Kavous. Grouping of genotypes using cluster analysis based on stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), yield index (YI) and plant yield in normal and stress condition allocated them to three clusters sensitive, semi-sensitive and tolerant in both of regions. According to the results, genotypes 8, 9, 11, 25, 34, 37, 42, 44, 49, 63, 66 and 86 identified as tolerant genotypes in both regions. In addition, cluster analysis based on microsatellite markers divided lines and varieties to three groups. Comparison of three dendrograms represented a high conformity among clustering. In addition, the stepwise regression analysis revealed Satt454, Satt142, Satt648 and Satt345 had a significant relationship to tolerant indices and explained between 4-15 percent of variation variably. The results could be a conformation to importance of these microsatellites in association with genomic regions related to drought tolerance in present genetic background. It is expected to use of these validated markers to improve of soybean against to drought stress.

The present investigation was carried out to study the variability, heritability, correlations and path coefficient analysis in 14 Kabuli type chickpea genotypes during three successive cropping seasons (2011-14), in a randomized complete block design with four replications. Combined analysis suggested significant differences between genotypes for most of characteristics. The highest phenotypic coefficients of variation (PCV) were obtained for seed yield, number of pods per plant, and number of seeds per plant, respectively. Furthermore, the highest genotypic coefficients of variation (GCV) were determined for seed yield, biomass yield and plant height, respectively. These results revealed that these traits could be improved via selection. High heritability coupled with high genetic advance as percentage of mean was observed for seed yield, number of seeds per pod and 100 seeds weight showed that phenotypic selection for these traits might be effective. Seed yield had positive and significant correlations with biomass yield and number of primary branches, thus selection for these traits could improve seed yield in chickpea. Number of seeds per plant, followed by number of primary branches, 100 seeds weight and biomass yield had positive high direct effects on seed yield. Meanwhile, number of primary branches, number of secondary branches and number of days to flowering could be used as an indirect selection criterion for higher seed yield.