مجله تولید و فرآوری محصولات زراعی و باغی
سال ششم شماره 2 (تابستان 1395)

Cold stress is one of the most important environmental stresses for rice especially in temperate and high elevation areas. In present study, the effect of different temperatures, as the main plot, including 25 (control), 10 and 5°C on 12 rice cultivars (including Champa Yasouj, Gerde, Lenjan Askari, Kaamfirouz, Kohsar, Shafagh, Domsiya Mamassani, Dular, Gharib, Hasan saraei, Mosa Tarom and 304) as the sub plot, was investigated using a split plot experiment based on a completely randomized design with 3 replications. According to the results of ANOVA, the effects of temperature, cultivar and their interaction were significant for all measured traits, indicating that there was high genetic diversity among the studied cultivars. Means of all studied morphological traits decreased in cold stress condition relative to non-stress condition. Genotypic and phenotypic correlation coefficients showed that shoot (seedling) related traits such as shoot fresh and dry weights and shoot length could be used for indirect selection for chilling tolerance in cold stress conditions at seedling stage. Based on cultivar grouping using the 3-dimensional plot of STI, YS and YP, Gharib and Champa Yasouj cultivars were identified as the most suitable cultivars in both cold stress and non stress conditions. Most of the studied cultivars including Gerde, Lenjan Askari, Kaamfirouz, Kohsar, Domsiya Mamassani, 304, Mosa Tarom and Hasan Saraei were found to be chilling sensitive cultivars at the seedling stage. Therefore, crosses between chilling resistant (Gharib and Champa Yasouj) and chilling sensitive cultivars will be useful for detecting transgressive segregation and improving cold stress tolerance in rice breeding programs.

Identification and evaluation of indigenous genotypes of fruit trees are matter of consideration at the first step of the breeding programs. In order to study genetic diversity and to identify promising genotypes, 14 different genotypes of walnut in Minoodasht region in Golestan province (north of Iran) were evaluated. Traits such as nut shape, kernel color, ease of removal of kernel halves, kernel weight, nut length, and nut widths were measured. Correlations between traits were significant at 1% and 5% percent statistical levels in most cases. Application of principal component analysis indicated that 7 main principle components (PCs) explained 91% of the total variance. Cluster analysis based on all traits was drawn; genotypes were divided into 3 groups. Presence of a great degree of variability in fruit characteristics of the studied traits is suggestive of a notable potential of these trees for breeding walnut cultivars

To investigate the effect of on-farm seed priming and bio-fertilizers at different phosphorus levels on some physiological indices of chickpea (Cicer arietinum L.) a factorial experiment was conducted in spring 2013 in a randomized complete block design with 3 replications at the Agricultural Research Station of Bu Ali Sina University in Hamedan, Iran. The factors consisted of phosphorus fertilizer (0, 50 and 100 percent of recommended phosphorus fertilizer) bio-fertilizer (mycorrhizae, Barvar2, both of them and no-application) and on-farm seed priming (priming with conventional water and no-priming). The results showed that priming increased all growth parameters especially maximum leaf area index, colonization percent and seed yield, by 44, 7 and 27%, respectively. Priming increased the mycorrhizal symbiosis percent by 6.8%. Application of bio-fertilizers, especially the simultaneous application of mycorrhiza and Barvar2 at 50 percent phosphorus, compared with the control treatment resulted in 27.4, 13.8, 8.2 and 29.5% increases in maximums of leaf area index, crop growth rate, total dry matter and seed yield, respectively. Mycorrhizal symbiosis with chickpea roots could reduce phosphate fertilizer application without reducing the physiological indices of chickpea.

This experiment was conducted to evaluate the effects of salt stress on some agro-physiological traits in ten varieties of bread (Triticum aestivum L.) and durum (Triticum turgidum L.) wheats in seedling stage. A greenhouse experiment was carried out as a split plot experiment based on a completely randomized design with four replications in hydroponic condition. Different agronomic and physiological traits (such as Na, K, Ca contents and relative water content (RWC)) were studied. Salinity showed significant effect on all of the studied traits, except for root dry weight and the ratio of Naﰦ. Increase in NaCl level led to significant reductions in all studied traits. The studied genotypes showed significant difference for radicle length, leaf length, seedling dry weight, leaf dry weight, root dry weight, RWC and Na, K, Ca concentrations and Naﲯ and Naﰦ ratios. The genotype × salinity interaction was significant for RWC, Na, Ca and Naﰦ. The salt stress increased the leaf Na while it decreased the K and Ca2 concentrations. The greatest shoot dry weight (0.035 g), root dry weight (0.024 g) and Naﰦ ratio (1.71) were found in genotype Alamot (bread wheat) and the greatest plantlet length (12 cm) was observed in genotype Verinak. The greatest rootlet length (14.63 cm), dry weight of seedlings (0.057 g), RWC (82.20%), membrane stability (0.59), K (3.38 mg/g dry weight) and the smallest Naﲯ ratio (0.17) were detected in genotype Toos (bread wheat). The genotype Toos was identified as the most tolerant genotype to salt stress.

Application of organic manure in organic farming and long-term mineralization may lead to residual effects on the succeeding crop. So, residual effects of combined cattle manure and urea fertilizer of previous crop (black cumin) on growth and yield of pea were examined in a randomized complete block design. Treatments included of cattle manure (CM), urea (U), three ratios of CM full dose application (2:1; 1:1; 1:2) and three ratios of CM split application (2:1; 1:1; 1:2), and unfertilized control to previous crop (black cumin) in 2012. Pea planted without any fertilizer in 2013. There was no significant difference between control and residual of urea treatment for some parameters including dry matter in flowering stage, plant nitrogen and phosphorus concentration, plant height, yield components, grain yield and biological yield of pea. Biological and grain yields were greater under both residual of cattle manure treatment and integrated treatments compared to residual of urea treatment. The highest grain yield (4000 kg ha-1) was observed in residual of CM:U full dosed application treatment, to the extent that grain yield in this treatment indicated a 1.5-fold increase in comparison with residual of urea treatment. The highest biological yield (8325 kg ha-1) was obtained in residual of CM treatment, though it was not significant different from that of residual of CM:U (1:2) treatments. In general, although residual of urea fertilizer did not leave a notable effect on pea production, but production of this crop relying on residual of cattle manure deems effective to lowering of fertilization cost and ameliorating environmental contaminations.

To examine the response of three rapeseed varieties to salinity stress, a pot experiment was conducted in a glasshouse using a factorial experiment based on a randomized complete block design with three replications. Three levels of NaCl (0, 100 and 200 mM NaCl) were imposed as the salinity treatments at root establishment (leaf 4) stage. In this study, sodium (Na) and potassium (K) concentrations and Kﳖ ratio were compared in different tissues in three varieties of rapeseed (PP-401-15E, Hyola401 and Hyola60) known to differ in salt tolerance, 30 days after salt treatment commencement. Effect of salinity was significant on all measured characters. The decline in shoot and root biomass and grain yield of salt sensitive genotype (PP-401-15E), were higher than those of the salt tolerants (Hyola401 and Hyola602) in response to salt stress. It seemed that the decrease in shoot biomass was primarily due to the osmotic effect of the salt, rather than the Na+specific effects. The salt tolerant genotypes accumulated smaller quantities of Na in the shoot and root, indicating that the degree of salt tolerance in these genotypes depend upon the degree of salt exclusion from the plants. The salt sensitive genotype maintained a smaller Kﳖ ratios in youngest fully expanded leaf than the salt tolerant genotypes. The ion partitioning capability in rape, thus, can considerably improve its salt tolerance. Relative membrane permeability was more notably increased in 200 mM NaCl in sensitive genotype (PP-401-15E) than the tolerant ones, and hence, can be used as selection criteria for improving salt tolerance.

Information about combining ability of inbred lines and genetic variance components of different agronomic traits is a prerequisite for improving the productivity of sunflower hybrids. For this purpose, 20 hybrids obtained from the crosses between five cytoplasmic male sterile lines with four fertility restorer lines were evaluated in a randomized complete blocks design with three replications in the Agricultural Research Station, University of Tabriz, Tabriz, Iran in 2009. Analysis of variance indicated significant differences between the hybrids for most traits and therefore it was possible to estimate genetic variance components through line × tester method. Results showed that plant height, head diameter, 1000-seeds weight and oil content were under the control of additive gene effects. Over dominance gene effects were observed for time of flower initiation, stem diameter and grain yield. This justifies the production of hybrid varieties. Male sterile line 52 and R50 restorer line had a better general combining ability for seed yield. Hybrids 52 × R26 and 222 × R50 had the highest specific combining ability. The results of this study indicated that due to existence of genetic variability for agronomic traits in genetic materials and presence of combinations with suitable combining ability, production of superior sunflower hybrids is feasible by selection and hybridization.

Chlormequat chloride (CCC) as one of the most important growth retardants has been used for manipulation of growth and yield of cereal crops; however, the effect of CCC has not yet been well understood under drought stress conditions. Therefore, one greenhouse and a field experiment were conducted to examine the effects of CCC on yield and yield components of wheat in drought conditions at College of Agriculture, Shiraz University during 2012-2014 growing seasons. The treatments in greenhouse were application and no-application of CCC, wheat cultivar (Marvdasht, Shiraz and Chamran) and irrigation regimes (100%, 75% and 50% of FC); while the treatments in filed were different CCC concentrations (0, 3 and 5 g L-1) and drought stress levels (no-, light-, moderate- and severe-drought). The results showed that under both greenhouse and field conditions, drought stress at different levels decreased yield and yield components of wheat cultivars. However, CCC improved drought tolerance in wheat with increasing yield and yield components; under field conditions, positive effects of CCC were enhanced with increasing its concentration up to 5 g L-1. The positive effect of CCC was greater under control and light stress compared to under severe stress conditions. In the greenhouse study where Marvdasht, Shiraz, and Chamran cultivars were evaluated, Chamran cultivar produced the highest grain yield under both normal and drought conditions; although Shiraz cultivar was found more responsive to CCC. Overall; drought stress reduced growth and grain yield of wheat crop; however, CCC could compensate, at least in part (i.e. 30% to 60%) for the latter reductions.

Citrus species are classified as a sensitive group of trees to salt stress, but the levels of their sensitivity or tolerance to salt are different among cultivars. In order to evaluate the effects of salinity stress on pollen germination of some citrus cultivars, an experiment was performed in factorial, based on completely randomized design in three replications with Cleopatra mandarin (Citrus reshni) and Poncirus trifoliata as tolerant and sensitive controls along with 13 genotypes. Pollen grains of these genotypes were cultured in media containing different levels of sodium chloride (0, 0.87, 1.6, 2.4, 3.1 dS/m) along with 15% sucrose, 0.7% agar and 100 mg/L boric acid. In order to understand the biochemical responses of pollen grains to salt stress, they were cultured in liquid media with three levels of salinity (i.e. 0, 0.87 and 1.6 dS/m) and then the amounts of total protein and enzyme activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) were evaluated. Significant differences of pollen germination (P ≤ 0.01) were observed in different salinity levels, but there were no significant differences in pollen tube growth. Pollen germination in Cleopatra was greater in comparison to Poncirus trifoliate, indicating that Cleopatra is a tolerant cultivar. The amounts of total protein and enzyme activities of SOD and APX were influenced by genotypes, salinity levels and their interactions (P ≤ 0.01). Considering the fastness and accuracy of this type of experiment, the evaluation of citrus pollen responses may, potentially, be hired as an initial screening criteria for detecting salt-sensitive varieties from the tolerant citrus ones.

In order to grow strawberry in Chaharmahal and Bakhtiari, growth, yield and fruit quality was evaluated among eight commercial strawberry cultivars including: Selva, Camarosa, Pajaro, Paros, Queen eliza, Kurdestan and Merak. This experiment was conducted in Agriculture and Natural Resources Research Center of Shahrekord through a RCBD design with three replications for four years (2008-2011). Vegetative and phenologic traits, yield components and fruit quality were recorded. Significant difference was observed among cultivars in all of the measured traits. These differences showed that ecological requirements in strawberry are cultivar-specific. Genotype by year interaction was significant for most of the traits, indicating that genotypes respond differently to climatic conditions of different years. Among cultivars studied, Queen eliza was found superior to other cultivars in terms of fruit yield, size and weight. A greater number of crown and inflorescence per plant and a larger berry contributed to higher yield in Queen eliza. Since cultivar Kurdestan indicated adaptability to climatic conditions of cold regions and it has a unique aroma and flavor, it could be recommended for local markets.

Drought is a climatic anomaly that associates with a significant decrease (lack) of precipitation and water resources availability, which spreads on vast temporal and spatial scales, and significantly affects various aspects of life and environment. One of the most common methods of drought assessing and monitoring is calculating drought indices (DIs). Drought areal and temporal extent and its severity are determined by these indices. In this study, an aggregate drought index (Hydro-Meteorological) has been developed for the assessment of hydrological and meteorological droughts in Sarbaz river basin located in southeastern of Iran. The Aggregate Drought Index (ADI) comprehensively considers all physical forms of drought (meteorological, hydrological, and agricultural) through selection of variables that are related to each drought type. In this case, monthly values of Stream flow Drought Index (SDI) and Standardized Precipitation Index (SPI) indicators were used for four similar reference periods with principle component analysis and aggregate hydro-meteorological index was defined based on its first component. The study time span was set between 1981-82 to 2010-11, which begins of October in Iran. Results based on the aggregate drought index (ADI) revealed that a long period of hydro-meteorological drought occurred from 1999-2000 to 2005/06 in southeast of Iran, in which, 2003/04 water year has been extremely a drought year. The ADI methodology provides a clear, objective approach for describing the intensity of drought. This index is appropriately able to represent the behavior of Hydro-Meteorological droughts and recommended as an integrated index for assessing and monitoring of regional droughts. Finally, different states of hydro-meteorological drought have been extracted based on conventional regional thresholds, and have been modeled by Markov chain. This made the estimation of drought state transition frequency possible, and made the prediction of next drought state time more real. State transition frequency matrices, are the main instruments for predicting drought states in real time. Results of validation tests and conforming the predicted results with real data indicate that predicting hydrological drought state transitions in the study area using Markov chain method is valid.

This research was conducted to evaluate genetic variation and estimate genetic parameters of forage yield and related traits in Dactylis glomerata. Twenty five half sib families derived from poly cross of 25 parental genotypes were evaluated under two moisture environments (normal and drought conditions) according to a randomized complete block design in Research Farm of Isfahan University of Technology. Results indicated that there are significant statistical differences and high genetic variation among the families for most of the studied traits. Drought stress significantly affected all forage related traits (except for leaf to stem ratio), leading to decreases in a majority of them. Mean of forage yield was decreased by 53.48 percent due to drought stress. Genotypic coefficient of variation under non-stress condition ranged from 1.78 to 45.1 and under drought condition ranged from 1.7 to 30.4, indicating a high genetic variation in this germplasm. The highest narrow sense heritability was related to crown diameter in both moisture environments. Narrow sense heritability for dry forage yield was 52% at non-stress and 45% at stress conditions. Based on dry forage yield, genotypes 2, 5, 8, 13 and 15 showed a higher general combining ability in both moisture conditions and, therefore, are potent to be used for developing synthetic varieties.

Plant growth promoting rhizobacteria (PGPR) have been proposed as a useful tool for enhancing plant growth. However, only few studies have examined the application of PGPR in in-vitro plant micropropagation. This study was aimed at evaluating the effects of plant growth promoting rhizobacteria (PGPR) and hormone levels on in-vitro micropropagation of Peperomia. The experiment was conducted in a factorial design based on completely randomized design with three replications. Factors comprised of plant growth promoting rhizobacteria (including 0=control (without bacteria), 1=Azospirillum lipoferum, 2=Pseudomonas fluorescent) and hormone levels (including 0=control (without hormone), 1=1.5 mg/l IAA 1 mg/l 2ip and 2=double the treatment 1). Before planting, medium surface was inoculated with 0.08 ml of liquid culture of bacteria and then sterilized axillary buds were cultured. Growth characteristics were measured at two and four weeks after planting. Bacteria and hormone interaction effect was significant in terms of total root length and mean root length. Treating with Azospirillum (without hormone) led to a greater root number, compared to other treatments. Bacteria inoculation had a significant effect on shoot length and leaf number. Inoculation with both bacteria resulted in a greater shoot length compared to control, i.e. it led to a 1.5-fold increase in shoot length. Concomitant application of bacteria and hormone led to a decreased leaf number. In general, bacterial inoculation appeared to be more beneficial to the rooting attributes.

In order to evaluate the effect of drought stress and nitrogen (N) fertilizer levels on yield, yield components and protein content of two barley cultivars (Yousef: six-rowed and Nimrouz: two-rowed), field experiments were conducted at the Fars Agricultural Research Center – Zarghan Station, during 2010-11 and 2011-12 growing seasons. The experiment was carried out as split-split plot based on randomized complete blocks design, with 3 replications. Irrigation regimes (full irrigation (W), 75% W; as mild drought stress and 50% W; as severe drought stress) were considered as main plots, nitrogen levels (0, 60 and 120 kg N ha-1) as sub plots, and the barley cultivars as sub-sub plots. In 2011-2012, rainfed treatment was included in the study; however, the other treatments were similar between two years. Results showed that the effect of irrigation regime, N rate and barley cultivar were statistically significant on grain yield, yield components, protein percent and protein yield in both years. Averaged over all treatments, grain and protein yield of the Nimrouz cultivar were higher than the Yousef under severe deficit irrigation and rainfed conditions. In the first year (with year – round 209 mm rainfall), mild drought stress significantly decreased the grain yield of both cultivars (8% and 12% in Nimrouz and Yousef cultivars, respectively). However, in the second year (with year – round 300 mm rainfall), grain yield of the Nimrouz cultivar was not significantly decreased by mild drought stress. There was a significant irrigation × N interaction effect on grain yield in both years. At full irrigation condition, grain yield was increased due to the application of up to 120 kg N ha-1 (28% and 26% as compared to control in the first and second years, respectively), however, at the other irrigation regimes, grain yield was increased due only to the application of up to 60 kg N ha-1. Overall, the Nimrouz cultivar could be recommended for severe drought stress and rainfed conditions. Furthermore, this genotype may receive 60 kg N ha-1 when grown under moderate drought in the years with 300 mm rainfall (such as the second year of this study).