جستجوی مقالات مرتبط با کلیدواژه « cultivars » در نشریات گروه « زراعت »

Due to the trend of population growth, the need to produce more potatoes by improving agricultural management is inevitable. One of the important challenges in agriculture is the management of weeds that, if not controlled, can lead to the destruction of agricultural products and decrease the productivity of agricultural lands. The use of chemical pesticides in agriculture in addition to being able to harm human and animal health, but also lead to environmental pollution and weed resistance to pesticides. For this reason, searching for non-chemical methods of weed management is of particular importance. Today, many believe that the key to successful weed control, especially in sustainable agricultural systems, is the use of cultivars with high competitive ability. This experiment was carried out in 1400-1401 and 1401-1402 on potato plant as a split plot in 3 replications. The first factor was the cultivation of three different potato varieties (Agria, Jely and Lady Rosetta) and the second factor included 5 types of management (complete weeding, rye cover crop, clover cover crop, paraquat herbicide and control). In total, rye, paraquat and clover treatments reduced the dry weight of weeds by 53.63%, 2.40% and 48.36%, respectively. Potato tuber yield increased by 63.75%, 53.21%, 47% and 1.72% in weeding, rye, clover and paraquat treatments compared to the control. According to the results, it was said that cover plants appeared effectively in reducing the density of weeds. The speed of height increase and the percentage of cover were also different in all three cultivars. In the trait of height Agria > Jeli > Lady Rosetta and in the percentage of cover Lady Rosetta > Agria > Jeli appeared.

This research was carried out in order to investigate the effect of irrigation regimes on morphological traits of root and shoot of safflower genotypes.

A field experiment has been conducted via polyvinyl chloride (PVC) pipes at research field of Seed and Plant Improvement Institute in Karaj, during 2019-2020. A factorial experiment has been laid out in a randomized complete block design with three replications. This study deals with six genotypes of safflower (Varamin landrace, Hamand landrace, Kazakhstan genotype and Amir, Goldasht and Pernian cultivars) in two irrigation regimes, including full irrigation (control) and drought stress (Irrigation after depletion of 40% and 80% of soil available moisture respectively) treatments.

The results showed that under drought stress conditions, root length and root diameter have increased by 28.6% and 13.6%, respectively and root dry weight, leaf relative water content (RWC), number of bolls, number of seeds per plant and seed yield per plot and was decreased by 23.6%, 15.2%, 25.4%, 63.3%, and 74.9%, respectively. Under full irrigation conditions, Amir with suitable root system (root dry weight 7.7 g and root length 71 cm) and maximum number of seeds had the highest seed yield (5.03 g per plot). In addition, under drought stress conditions, Amir cultivar had early flowering, maximum root dry weight and length, highest activity of catalase and peroxidase enzymes, and the highest seed yield per plot (1.67 g).

Generally, Amir cultivar had more seed yield due to having a suitable root system and superior agronomic characteristics and was selected as the superior genotype.

This study was conducted to investigate the effects of different levels of cut irrigation on yield and quantitative and qualitative characteristics of cultivars wheat in the crop year 2017-18 in Shahriar region. This research was carried out as split plots design a randomized complete block with two cut irrigation and cultivars factors in 63 treatments and three replications. The main factor of irrigation treatment in three levels including: normal irrigation I0, cut irrigation in flowering stage I1 and cut irrigation in grain filling stage I2 and cultivars in 21 levels as a sub-factor including; Chamran, star, Sirvan, Sivand ,Arg, Parsi, Barat, Narin, Heidary, Ofogh, Rakhshan, Baharan, Sepahan, Aflak, Mihan, Zare, Gonhad, Orum, Saison, Gascogen and Mehregan. The results of analysis of variance showed that 1000-seed weight, grain yield, total yield, stomatal conductance, canopy temperature, leaf proline, cell membrane stability, grain gluten, SOD antioxidant enzyme and MDA degradation biomarker were affected by the main effects of irrigation levels and cultivarsand interactions were significant at the level of 5% and 1%. The highest grain yield (10857.2 kg.ha-1), total yield (44092.8 kg.ha-1) and stomatal conductance (236.08 molH2o. m2.s-1) were allocated to Normal irrigation and Rakhshan cultivar treatment. The lowest grain yield (1467.9 kg.ha-1), total yield (11496.7 kg.ha-1) and stomatal conductance (44.81 mmolH2o.m2.s) were obtained from cut irrigation at flowering stage and Ofogh cultivar treatment. However cut irrigation treatment at flowering stage and Ofogh cultivar obtained the highest canopy temperature (19.827 C), proline leaf (0.994 µg.gFw-1) and the lowest canopy temperature (13.126 C), leaf proline (0.416 µg.gFw-1) and cell membrane stability (171.14 µmos.cm) was observed from normal irrigation and Rakhshan cultivar treatment. The highest antioxidant enzyme superoxide dismutase SOD (19.06 U.mgprotein) and MDA (40.68 Ƞmol. gFw-1) were achieved from cut irrigation at flowering stage and Gasgogen cultivar treatment. The results showed that the tolerant cultivars were less affected by drought stress. And by less producing organic matter such as proline and degrading enzymes and biomarkers, they maintained their yield at an acceptable level.

Sugar beet (Beta vulgaris L.) is one of the important commercial crops that supply approximately 35% of the world’s sugar and is widely cultivated in arid and semi-arid regions. Drought is one of the most important growth restricting environmental factors for crop species in arid and semi-arid regions of the world. Crop losses resulting from abiotic stresses such as drought or salinity can reduce crop yield by as much as 50%.

to investigate the evaluation of different genotypes of sugar beet (Beta vulgaris l.) in terms of biochemical and antioxidant properties under normal conditions and water deficit conditions excrement was conducted in split-plot design based on complete random blocks with three replications in Miandoab Agricultural and Natural Resources Research Station at 2017-18 Crop seasons. Irrigation regimes at two levels, (normal Irrigation after 90 mm of evaporation and drought stress after the 10-leaf stage of sugar beet based on 200 mm of evaporation from the Class A evaporation pan) signed to the main plot, and 18 sugar beet genotypes were assigned to sub-plots. In this research root yield, coefficient of sugar extraction, Guaiacol peroxidase, Polyphenol oxidase, Superoxide dismutase, and proline content were measured. After collecting the data, the data were analyzed using SAS software version 9.1 and the comparison of the average of the studied characteristics was performed using LSD test at the probability level of five percent.

In the present study, the effect of the irrigation regime on all studied traits was significant except for the sugar extraction coefficient at the level of probability of 1%. Among the genotypes studied significant difference was observed in terms of all the studied traits, at the probability level of 1% Interaction of irrigation regime with genotypes on root yield, sugar extraction coefficient, guaiacol peroxidase, polyphenol oxidase, and proline content at 1% probability level and superoxide dismutase at 5% probability level was significant. The results showed that water deficit stress reduced root yield by 17.38% compared to normal irrigation conditions, while the content of glycol peroxidase, polyphenol oxidase, superoxide dismutase, and proline under water deficit conditions was an increase compared to normal irrigation conditions by 118.86, 82.1, 103.61 and 113.92 percent respectively. genotypes Mean comparison in terms of root yield showed that genotype No. 10 with an average of 85.77 t / ha under normal irrigation and 72.14 t / ha under water deficit stress had the highest root yield. Under normal irrigation conditions, the highest guaiacol peroxidase, polyphenol oxidase, superoxide dismutase activity, and proline content were belonged to genotypes 21, 15, 4, and 13, respectively. While underwater stress conditions, the highest values of these traits were recorded in cultivars 10, 20, 19, and 3, respectively. Based on the results of regression analysis under normal irrigation conditions, the Sugar Extraction Coefficient and proline content with the explanation of 80 percent of root yield variation were identified as the most important traits. Based on the results of path analysis, the two traits, directly and indirectly, showed a positive effect on root yield. Underwater deficit stress proline content, guaiacol peroxidase, and superoxide dismutase with 66.3% explanation of changes in root yield Were identified as the most effective traits on root yield. Besides, the mentioned traits had a positive effect on root yield based on the results of path analysis both directly and indirectly.

Among the studied genotypes, cultivar F-20851 had the highest root yield in both irrigation conditions compared to other cultivars, so it can be concluded that the genotype has a high genetic potential for root yield production in different environmental conditions. Among Iranian cultivars, except for Paya cultivar, other cultivars had low ranks of root yield in both environmental conditions. It can be concluded that in addition to root yield, other enzymatic and biochemical properties of Iranian cultivars should be worked on to be competitive with foreign cultivars. In this study, proline content had a positive effect on root yield in both environmental conditions, so improving proline content could be a way to increase root yield in different environmental conditions.

In order to evaluate the effect of row spacing and seed rate on yield and yield components of safflower cultivars, a field experiment was conducted in research field of Seed and Plant Improvement Institute, Karaj, in 2015-2016 and 2016-2017 cropping seasons. A factorial experiment based on a randomized complete block design with three replications was conducted in the field experiments. Factors of the experiment consisted of two row intervals of 30 and 60 cm, two plant distances of 40 and 60 plants per square meter, and three safflower cultivars namely Padideh, Golmehr and Goldasht. In this study, the simple effect of row spacing on yield and yield components, simple effect of density on yield, oil yield, and number of grain per boll, and the interaction effect of row spacing × plant density on number of grains per boll were significant. Also, three safflower cultivars had significant differences for plant height, grain yield and oil yield. The results of this study showed that the highest grain yield was obtained at 30 cm row spacing (2312 kgha-1) and density of 60 plants per square meter (2263 kgha-1). Also, Goldasht and Golmehr had the higher grain yield compared to Padideh. Thus, the best recommendation for planting pattern of safflower cultivars in moderately cold areas is row spacing of 30 cm (two rows on stack) and density of 60 plants per square meter.

One of the problems faced by Phoenix dactylifera L growers in different parts of the country is the lack of a favorable fruit set for tissue culture seedlings of some cultivars recently. This study is conducted to investigate the effects of pollen of different cultivars on the fruit set of Phoenix dactylifera L tissue culture and offshoot palms of Barhi, Piaroom, and Mazafati cultivars in the garden of Jahrom Agricultural Research Station. During the years 2018 - 2019, in a factorial experiment, three factors have been performed in three replications with a randomized complete block design. The first factor involves different pollen with five levels (i.e., codes 7001 (control), 7005, 7013, 7030, and Boyer 11 obtained from tissue culture (B11)) with the second factor being the cultivar type in three levels (Barhi, Pyaram, and Mazafati), and  the third one, the type of seedlings, all applied on 90 ten-year-old trees in two levels (tissue culture and offshoot). Results show that the highest percentage of natural fruit set has been observed in Mazafati cultivar with 7013 and 7030 pollens and 7013 pollen in Barhi cultivar. The lowest percentage of natural fruit set belongs to tissue culture method in Barhi cultivar with pollen 7001 (control). In general, 7013 and 7030 pollens have been identified as the most suitable pollinator base to increase the percentage of normal fruit set and reduce parthenocarpic and fallen fruits of Barhi, Piaroom, and Mazafati cultivars obtained from tissue culture and offshoot.

The findings of previous investigations show that the best density to achieve high yields with most of the beans (Phaseolus vulgaris L.), including the local Khomein cultivar, stands roughly at 40 plants m2 (Mehrpooyan et al., 2010). There is no comprehensive information available on bean yield performance under drip tape irrigation. Common bean is widely cultivated in Chaharmahal and Bakhtiari province, however, given its high water consumption and due to drought spells in the region in recent years, its production has sharply declined. While common bean requires 7000 to 8000 m3 of water per hectare during the growing season (Alizadeh, 2003), farmers use more than 15000 m3 of water per hectare for beans throughout the growing season. The use of drip tape irrigation can reduce water consumption in beans. The use of this irrigation method requires changing the planting method and proper arrangement of cropping systems. The objective of the present study was to determine optimum plant arrangement in common bean varieties under drip tape irrigation conditions.

In this study, a factorial experiment was conducted in a randomized complete block design with three replications in spring and summer of 2016 and 2017 at Chahartakhte Research Station in Shahrekord region. The first factor was cultivar (Koosha chitti bean, Yaghut red bean and Dorsa white bean), and the second factor was the planting arrangement (row spacing of 75 cm with 2, 3 and 4 planting lines per row, and the row spacing of 60 cm with 2 planting lines on each row). Different traits at vegetative and reproductive stages of bean plants were recorded and at the end of the growing season, yield and yield components of the cultivars and water productivity were determined. The experimental data were analyzed by using SAS statistical program and the means were compared by Tukey test (p < 0.05).

The combined analysis of variance showed that plant height, number of seeds per pod, number of pods per plant, 100 seed weight, grain yield and water productivity were affected by bean cultivars and planting arrangement. The interaction effect of cultivar and planting arrangement was significant on 100 seed weight, grain yield and water productivity. The grain yield components were significantly difference among different cultivars. The highest number of pods, seeds per pod, 100-seed weight and grain yield were respectively recorded with Yaghut red bean, Koosha chitti bean, Koosha chitti bean, and Koosha chitti bean. The traits such as number of pods and weight of 100 seeds are controlled and affected by genetic and non-genetic factors such as environment. The number of seeds per pod is the most stable trait of beans and is mostly influenced by genotype (Salehi, 2015). The cultivars studied in this experiment exhibited differences in plant height, grain yield components, grain yield, and water use efficiency. Among crops, bean has the highest diversity in growth habit, seed size and maturity. There are a wide variety of genetic variations in bean pool genus. Therefore, due to genetic differences, under the same climatic conditions, the occurrence of different phenotypes (grain yield, number of pods per plant, 100 seed weight, etc.) is inevitable, and the difference between them is the result of genetic differences and their different response to the environment. Drip tape irrigation produced the highest water use efficiency when three or four lines of beans were planted on a 75 cm row, while plant density was constant for all treatments. The highest water use efficiency was obtained from Koosha chitti bean, which can be explained by the highest grain yield.

The highest grain yield and water productivity were obtained from Koosha chitti bean cultivar. Although the four lines per row arrangement on the 75 cm row gave the highest seed yield and water productivity, it did not differ significantly with the three lines per row on the 75 cm row. Therefore, if the goal is to reduce water consumption and increase water productivity, planting three or four lines per row can be considered on 75 cm row, but because of the ease of planting three lines per row on 75 cm row, it can be recommended to farmers.

In studying the phenological stages of crops, the growing degree-days (GDD) gradients is considered as an alternative to counting the calendar days. Genetic diversity of 86 Iranian cultivars and 184 Iranian wheat landraces were studied based on the phenological stages (day to booting, day to flowering, day to maturity and GDD of these stages) along with grain filling period, thousand grain weight and grain yield during the 2013-14 and 2014-15 growing seasons. The results revealed that there is a significant difference between cultivars and landraces and studied traits were able to effectively distinguish between cultivars and landraces. On the other hand, the results indicated that genotypes with different growth habits have a significant difference in terms of most of the phenological traits. That is implied that either directly or indirectly has been occurred on increasing the length of the grain filling period along with grain yield. Since the diversity of phenological traits was higher in landraces, they can be a valuable source of choice for improving these traits. Finally, due to the importance of the phenological stages, it is recommended that these traits be taken into account in terms of yield and yield components and GDD index can be used to obtain more accurate results.

Increasing the world's population and improving living standards is one of the reasons for increasing the production of oily crops for arable consumption. In this regard, rapeseed is superior to other oilseed crops in the country due to its positive traits such as resistant to cold weather and drought stress, salt tolerance and higher yield per unit area. The factors affecting the yield of plants are the use of suitable cultivars adapted to the climatic conditions of each area in appropriate planting density, in such a way that there is at least a destructive competition between the plants. Regarding the fact that each plant, or, in a better way, indicates a specific reaction to environmental factors, and also due to the high capacity of rapeseed for improving the yield as a result of environmental factors, this study aimed to determine the most suitable plant density and variety for improving yield and yield components of rapeseed.

In order to investigate the effect of different densities on yield and yield components of different rapeseed varieties, a factorial experiment was conducted in a randomized complete block design in a research farm of Gharakhil Agricultural Research Center in Ghaemshahr in 2017-2018, The treatments consisted of five intervals on rows of 3, 3.5, 4.5, 6 and 9.5 cm, respectively, with densities of 66.67, 57.14, 44.44, 33.33 and 21.05 plant, respectively. Second factor for this experiment was included four canola cultivars: Hayola 401, Agamaks, Hayola 4815 and Terrap, which were performed in three replications.

The results showed that the highest biological yield and seed yield (11150 and 2942 kg ha-1) were related to Hyola 401 cultivar with 44.44 plant m-2. The main effect of density and variety on harvest index, 1000 seed weight, number of pods, number of seeds per pod and number of branches were significant. The density of 44.44 plants per square meter was the highest in pod (21.58), 1000 grain weight (4.24 gr) and harvest index (59.16 percent). The results also showed that the highest number of branches and pods per plant was related to density with density 33.33 plant / m2. In all studied traits in this study, except for the number of branches, the Hyola 401 cultivar showed better performance than other cultivars.

The results showed that there is a significant difference between plant densities and different cultivars for all measured traits. The results of this study showed that Hyola 401 cultivar with 44.44 plants m-2 had the best result in terms of biological yield and grain yield. Therefore, according to the results, Hyola 401 cultivar and 44.44 plants m-2are recommended for achieving high yield in rapeseed.

To study the response of dryland wheat (Triticum aestivum L.) cultivars to the exogenous application of glycine betaine, a field experiment was conducted as a factorial based on randomized complete block design with four replications at Field Research at Islamic Azad University, Kermanshah,Iran in 2015-2016. Treatmens included four wheat cultivars, Sardari and Azar 2(drought resistant, Rasad and Owhadi(drought susceptible), and four levels of glycinebetaine application (zero or distillate water as control, 50 mM, 100 mM and 150 mM) were sprayed in two growth stages; early heading and early grain filling. The results showed that in most traits there was a significant differences between the cultivars, and Sardari cultivar was superior to other cultivars in most traits, with the highest grain yield and proline content 3571.88 kg/ha and 29.94 μmol/g respectively. Glycinebetaine spraying at 100 mM had significant increase in spike length, 1000 seeds weight, grain yield, harvest index and proline content. Interaction between cultivars and glycinebetaine concentrations showed that in 100 mM glycine betaine , only two drought resistant cultivars ,Sardari and Azar2, it was the highest and significantly different from other levels of spraying, but in the drought susceptible cultivars, Rasad and Owhadi, there was no significant difference in proline content for different levels of glycinebetaine concentrations, which may be due to the lack of changes in the incidence of related genes in response to osmotic stress. Overall,it can be concluded that there is a positive relationship between proline content and grain yield in drought resistant wheat cultivars.

It is of great importance in breeding strategies to know the relationship between grain yield and main agronomic traits and understand the trend of changes in traits during breeding history. To meet these objectives, 313 Iranian wheat genotypes including 203 Iranian landraces and 110 Iranian cultivars were planted in an augmented design along with three check cultivars repeated in seven blocks in 2014 on the research field of Agronomy and Plant Breeding, University of Tehran. In order to increase accuracy and decrease environmental variation, the experiment has been replicated in three different location. Linear regression analysis between investigated characteristics and year of cultivar release and year of collection of landraces showed that the grain yield and thousand grain weight were significantly increased in both cultivars and landraces while spike weight was only significantly increased in the cultivars. Plant height and spike length were significantly decreased only in the cultivars during 74 years of breeding programs. No significant changes, however, was observed in the landraces. Although the number of grain/spike was known as the most important and effective traits on grain yield based on the results of correlation and path analyses, there was no any significant change for this trait during breeding programs. Since there were high phenotypic and genetic coefficient of variation for this trait, it could be one the most important traits in future breeding programs.

Cereal Cyst nematode is one of the most important damaging nematodes of wheat and barley in the world. Cereal cyst nematode Heterodera filipjevi has wider distribution in cereal fields in the country. In this study, the effect of mentioned nematode was evaluated on 13 wheat rainfed cultivars and root micro-morphological in greenhouse and field condition. H. filipjevi were identified based on morphometric and molecular characters. The number of cysts, second stage juveniles (J2) and eggs, reproductive factors and anatomical aspects of the root were analyzed. The results indicated that at greenhouse conditions, the lowest milky cyst was related to Zagros cultivar with 1.75 number and the lowest number of cereal cyst nematode eggs and larvae and reproductive factors were related to the Kohdasht cultivar with 1.32 and 0.26 number per gram of soil. Obtained results classified cultivars in two ranges of resistant and sensitive to cyst nematode. In the field, the lowest number of cyst was related to Zagros with 185.33 per 200 g of soil. The lowest number of CCN eggs and larvae and reproductive factors were related to Kohdasht with 3.76 and 0.68 per g of soil. Root components studies, the highest thickness of cuticle, periderm and parenchyma was observed for the Rasad, Karim and Rasad cultivars with an average of 12, 33 and 41.33 micrometers and the lowest was recorded for Karim, Rizhav and Aftab with an average of 6.67, 19.33 and 23 μm, respectively. Cluster analysis was also divided the studied cultivars in two different categories, which this results had a remarkable similarities with Duncan's test results.

To study yield and different traits and select the suitable apple cultivar for Golestan province, some vegetative traits and fruit quantitative and qualitative characteristics of five commercial apple cultivars Golden delicious, Red delicious, Braeburn, Red spur and Fuji grafted on MM106 were evaluated in Shahkoh during 2013-2015 using a completely randomized design with three replications and three trees in each replication. The highest yield efficiency was 0.49 kg per cm2 of trunk cross area in Red spur cultivar followed by Braeburn, Fuji, Golden delicious and Red delicious. Maximum firmness (5.74 kgcm-2) was in Fuji cultivar and minimum (4.82 kgcm-2) in Braeburn.The highest amount of total soluble solids and acidity were in Golden delicious cultivar (13.37 and 1.45, respectively). Results of simple correlation analysis indicated the existence of significant, positive or negative correlations between some characteristics such as fruit dimensions and skin thickness and cultivar. Based on the obtained results and due to short season growth period in shahkoh mountains, early to medium season ripening cultivars and semi-standard to standard rootstocks can be recommended for cultivation in this region.

Bread wheat is known as the staple food crop and its quality properties are variable because of diffrences among cultivars, climatic conditions and farming systems. Due to the lack of adequate information about the quality of different bread wheat cultivars in the farmers’ fields, in this research quality and bakery properties (thousand grain weight, protein content, wet gluten and SDS) of grain samples of four different cultivars of bread wheat (irrigated and rainfed), collected from the farmers’ fields during two growing seasons 2013-14 and 2014-15, which grown on large areas in the country were evaluated. The results showed cv. Azar 2 had better quality than cv. Sardari cultivar by 11.46% protein, 26.3 wet gluten and 55.2 ml SDS in two growing seasons. On the other hand, the quality characteristics of Chamran and Pishgam irrigated bread wheat cultivars were notsignificantly different in different provinces. Also the lowest quality of wheat was observed in Kurdistan, Hamadan and Kohgiluyeh and Boyerahmad. This may be due to nutrient shortage in the soil of those provinces that are largely under rainfed production of wheat.

Due to the extension of olive cultivation in Fars province, in the recent years some cultivars cultivated by the gardeners have encountered with the problem of low productivity. This study was carried out in Fasa, Fars province for two years to examine the adaptability of eighteen imported and local oil cultivars, using a randomized complete block design with three replications. Various olive fruit characteristics such as fruit set, ripening index, oil contents in fresh and dry fruit weight, fruit weight and pulp/stone ratio were assessed in five years old trees. The results indicated that in two years Leccino and I-77 cultivars produced the highest percentages of fruit set. Crolea and Moraielo cultivars with 49.81% and 49.6% in 2011, and Nechara and Leccino with 49.81 % and 49.52% in 2012, respectively, had higher oil contents in dry fruit weight compared to the other cultivars. Based on the results of this study, some cultivars such as Hojiblanca, I-79, Rya Sebibna, Nechara, Pendolino, Ceratinia, Leccino and Corolea showing better characteristics, can be recommended for cultivation and be replaced by low yielding cultivars in these areas after complimentary investigation.

In order to evaluate the biological nitrogen fixation among the commercial cultivars of common bean (Phaseolus vulgaris L.), an experiment was carried out at Chahartakhteh Station (Shahrekord) of Agricultural and Natural Resources Research and Education Center of Chaharmahal and Bakhtiari province in 2012-2013. The experiment was arranged as randomized complete block design with twenty lines and cultivars of all types of common bean with three replications. Lolium (Lolium multiflorum L.) was used as non-fixation nitrogen check. During the growing season, samples from plants were taken at peak of flowering to determine the amount of nitrogen. The combined analysis of variance indicated that the bean genotypes had significant differences in biological nitrogen fixation. The highest rate of biological nitrogen fixation (104 kgha-1) belonged to Pak cultivar which had not significant difference with Daneshkadeh and Goli cultivars, but was significantly different from other genotypes. The highest number of pods per plant belonged to KS31169, the highest 100-seed weight was obtained from KS21191 and the highest seed yield was produced by Akhtar cv. with no significant difference with Dorsa, Dehghan and D81083 cultivars. In general, the results of this experiment showed that lines and cultivars of common bean have different biological nitrogen fixation ability which can be used in fertilizer management of bean cultivars in field.

In interspecific and intraspecific crosses, pre-zygotic barriers like pollen-pistil incompatibility may exist, and in the case that a parent is selected as male or female, this incompatibility may disappear. In this investigation seven high yielding commercial cultivars of potato (Agria, Savalan, Picasso, Caesar, Daifla, Luca and Satina) were reciprocally crossed with eleven promising potato clones in Ardebil Agricultural and Natural Resources Research Station during the summer of 2014 to obtain cheep TPS hybrids. The best cultivars and clones were appointed when they were as male and female. Results of two pollen fertility tests showed that cultivars Agria and Luca and clones AS10 and AS72 were sterile and did not produce fruit when participated as mate parents in crosses. Generally, when commercial cultivars were as female, the number of fruit and seed, seed weight, cross efficiency, strength and uniformity of germination and seedling growth were better.When commercial cultivars were considered as female parent and clones as male parent, Savalan, Caesar and Luca cultivars showed better traits than other cultivars. When clones were mate and commercial cultivars female, HS Clone and UT42 had higher percentages of fruit and seed set, crossing efficiency, percentage of seed germination and 100-seed weight. In crossing, when the commercial cultivars were male and clones were female parents, clones AS72 and AS10 had better traits than the other Clones.

This experiment was carried out to determine the effects of heat stress, due to different planting dates, on the peduncle anatomy of rice cultivars and their grain yields. It was performed in a split-plot experiment using randomized complete blocks design with three replications in 2006 and 2007 cropping seasons at the Shavoor Agricultural and Natural Resources Research Center of Khuzestan. Three planting dates (May 5th. with 20 days intervals), to expose rice cultivars to different tempratures, were assigned to main plots and cultivars (Hoveizeh, Hamar, heat tolerant, Ghermez Anbori, Champa, heat sensitive, and Danial, relatively heat tolerant) to sub-plots. The results of combined analysis showed that the effects of planting date× variety interactions were significant for all of traits, including air channel surface, large vascular bundles surface, xylem and phloem. This indicates that cultivars reacted differently to planting dates. Lowest and highest airchannels surface levels were related to 1st and 2nd planting dates (15492.23 and 21144.38 µm2) and to Hoveizeh and Champa cultivars (15492.23 and 23411.18 µm2) respectively. Lowest and highest xylem surface obtained in 3rd and 1st planting dates (741.37 and 898.03 µm2) respectively. But, lowest and highest level of large vascular bundles were optained in 2nd and 3rd planting dates (15514.20 and 15983.93 µm2)and for phloem (3121.68 and 3437.55 µm2)respectively. Based on these results it can be said that the reduction of large vascular bundles surface and phloem in 1st and 2nd planting date are mechanisms of water conservation and maintaining cell turgor pressure. Increasing xylem vascular bundle surface also, would facilitate availability of water to plant under drought stress conditions.

Ascochyta blight caused by Ascochyta rabiei (Pass.) Lab. is an important disease of chickpea in Iran and worldwide. Information about the races of the pathogen in different areas is necessary for improvement of resistant cultivars. In the present study physiologic races of 28 isolates of A. rabiei collected from five areas of Kermanshah province of Iran during 2013 and 2014, were determined using seven chickpea standard differential cultivars. Six different races were identified. Race 1 with seven isolates(25%), race 2 with five isolates (17.8%), race 3 with seven isolates (25%), race 4 with four isolates( 14.4%), race 5 with two isolates (7.2%) and race 6 with three isolates (10.6%) were the prevatent races in Kermanshah province. Races 1, 2, 3 and 4 with 23 isolates (82.1%) were distributed all over areas of the province, while race 6, the highly virulent isolate, was detected only in a restricted area in Sararood. Response of 48 genotypes of including improved cultivars, advanced chickpea lines and landraces were evaluated against the six identified races in greenhouse. The results showed that most of the genotypes were susceptible or highly susceptible to different races. Recently released cultivars, Adel and Azad, were moderately resistant to the highly virulent race 6 and resistant to the other races. The remaining genotypes were susceptible or highly susceptible to this race. Based on the results of this study, in addition to Adel and Azad cultivars, lines Flio 51-87-3c, ILC-3274 and LMR-165 which were resistant or moderately resistant to the most prevalent races 1, 2, 3 and 4, can be also recommended as resistant sources for the region.