جستجوی مقالات مرتبط با کلیدواژه "اثر متقابل" در نشریات گروه "زراعت"

The evaluation of the genotype × environment interaction effect provides valuable information regarding the yield of plant cultivars in different environments and plays an important role in evaluating the stability of the yield of breeding cultivars. Genotype × environment interaction effect, especially in stressful environments, are important limiting factors in the introduction of new cultivars; therefore, it is very important to know the type and nature of the interaction effect and reach the verities that have the least role in creating interaction effects. Various methods have been introduced to evaluate the interaction effect, each of which examines the nature of the interaction effect from a specific point of view. The results of different methods may not be the same, but the best result is obtained when a genotype with different evaluation methods shows similar results in terms of stability. The purpose of this research was to evaluate the genotype × environment interaction effect in experiments conducted in different environments, to determine the relationships between genotypes and environments and to introduce the most stable red bean genotypes.

In this research, 14 red bean lines along with Yakut, Ofog and Dadfar control cultivars were cultivated in the form of a randomized complete block design with three replications in Khomein, Borujerd, Shahrekord and Zanjan research stations for 2 crop years under the same conditions. After combined variance analysis, according to the significance of genotype × environment interaction, AMMI and GGE-Biplot analysis methods were used to determine the compatibility and stability of genotypes. After AMMI Analysis, the stability parameters of AMMI were calculated. In addition to the AMMI stability parameters, the simultaneous selection index was also calculated for each of the indices, which was the sum of the rank of the genotypes based on each of the AMMI stability indices and the average seed yield rank of the genotypes in all environments.

The significance of the double and triple interaction effects of genotype with year and place (environment) in this study showed that genotypes showed different responses in different environments, and in other words, the difference between genotypes is not the same from one environment to another, and in these conditions, the stability of grain yield can be evaluated. The contribution of about 2.5 times the interaction effect of genotype × environment from the total sum of squares, compared to the effect of genotype, indicated the possibility of the existence of mega-environmental groups in which some genotypes show their maximum performance potential in those environmental groups. Genotypes G12, G5 and G17 had the highest seed yield among the genotypes with yields of 3288, 3136 and 3111 kg per hectare, respectively. AMMI analysis showed that the first to seventh main components were significant at the 1% probability level, and despite the significance of all model components, the first and second main components had the largest contribution to the expression of genotype × environment interaction (66.5%). Based on AMMI1 biplot Genotypes G4, G5, G16, G17 and G12 had the highest values (positive and negative) of IPCA1. In contrast, genotypes G8, G3, G2, G7 and G11 had IPCA1 values close to zero. However, only the genotype G11 showed a performance higher than the average total yield and therefore it can be introduced as a stable genotype with high general compatibility. Based on AMMI2 biplot, genotypes G2, G7, G3 and to some extent G8 and G13 were introduced as stable genotypes, but only G13 genotype had a higher yield in all environments, so this genotype can be introduced as a stable genotype with good yield.; also, every two years, the same place under investigation had a high correlation with each other, so that Bro1 and Bro2 environments on the one hand and Kho1 and Kho2 environments and finally Zan1 and Zan2 showed a high positive correlation (the same effect) to create a mutual effect. In total of the simultaneous selection indices calculated based on AMMI analysis, genotypes G11, G17, G7, G13 and G12 were introduced as stable genotypes with high yield. GGE-Biplot analysis based on average yield and stability showed that genotypes G1, G2, G3, G8 and G7 had the highest general stability compared to other genotypes despite having the lowest yield. On the other hand, G12, G5 and G17 genotypes had the highest yield with less stability. No ideal environment was observed. But Kho1, Kho2 and Sha1 environments are closer to the ideal environment than other environments and they can be used to distinguish the studied genotypes to some extent. On the other hand, G12 genotype can be considered as a desirable genotype that has high average yield and high yield stability. In the same way, G17, G5 and G11 genotypes were in the next stage compared to the ideal genotype and to some extent they can also be considered as desirable genotypes.

According to all the results, G12 genotype can be considered as a desirable genotype that has a high average yield and also has yield stability, and G17, G5 and G11 genotypes were in the next stage.

Studying the nature of the genotype×environment interaction provides the possibility of identifying stable and compatible genotypes for breeders, and it has always been one of the important issues in the production and release of new stable and high-yield cultivars in breeding projects. The current research was conducted with the aim of identifying the response of genotypes in each of the studied areas, based on AMMI and GGE biplot models and better understanding of the genotype×environment interaction and determining the level of public and private stability of cultivars. Twenty facultative and winter wheat genotypes were cultivated and evaluated in nine regions (18 environments) during the two crop years of 2017 to 2019 in a randomized complete block design with three replications. In order to analyze the compatibility and stability of genotypes, AMMI and GGE biplot models were used. The results of AMMI analysis showed that the main effect of genotype, genotype×environment interaction effect and the first six principal components were significant at the 1% probability level. The first and second principal components explained about 51% of the sum of squares of the genotype×environment interaction effect. Based on SSiASV and SSiWAAS simultaneous selection indices, genotypes G13, G1, G3, G2, G6, G16, and G7 were identified as the best genotypes. Biplot analysis showed that the genotypes G1, G3, and G6 with average yield had the highest general stability compared to other genotypes. None of the genotypes can be considered as desirable genotypes that have high average yield and high yield stability, but genotype G16 and in the next stage the genotypes G1 and G13 were close to the ideal genotype. Polygon biplot model divided environments into two environmental groups (macro environment) and genotypes into four groups. The first environmental group included Kar1, Kar2, Qaz1, Qaz2, Ham1, Ham2, Mia2, Egl1, Jol2, Ard2, and Ara1 environments, with G16, G17, and G4 genotypes having the highest yield. The second environmental group included Mas1, Mas2, Mia1, Ard1, Jol1, Ara1, and Egl2 environments, and in this macro environment G2, G11, G7, and G12 genotypes had the highest yield. Finally, the examination of the relationships among the environments showed a very high correlation among the investigated environments, which indicated the similar behavior of the genotypes in the most of the tested environments.

Due to the increase in population and unfavorable environmental conditions, especially various stresses and the problem of water scarcity, evaluation of plant genotypes in various environments is inevitable. The interaction effect of the genotype and environment can be used as a mean by plant breeders to select the best genotypes/cultivars in plant growth environments (in one or more years).

In order to evaluate the stability of grain yield, this experiment was performed on 108 chickpea genotypes in the cropping years 2017-2018, 2018-2019 and 2019-2020 in the form of a randomized complete block design. By carefully planting, holding and harvesting operations, during the growing season and postharvest, seed yield, 100-seed weight, plant height, number of days to 50% flowering, number of days to maturity, number of pods per plant, number of main branches was recorded.

The results of combined analysis of variance showed that there was a significant difference between the genotypes in terms of plant height, grain yield, number of pods per plant, number of main branches. Comparison of mean grain yield showed that genotype number 10 had the highest yield (54.038 gram).significancy of GE interaction effect showed the response of genotypes within various environments so then it is possible to perform the stability analysis of genotypes and for this reason, the GGE biplot was used in parallel with some findings of AMMI model and mixed AMMI model (AMMI in conjunction with BLUP) which GGE biplot resulted that first 2 components accounted for 76.3 percent of total variation of grain yield and in this context varieties 1, 26, 60 and 101 acconted as ideal ones and so genotypes 32, 69, 76, 89, 90, 94, 98 and 108 mentioned as suitable genotypes compared to other genotypes and that 4th enfironment (year 3-Kermanshah) mentioned as ideal environment.

Considering the superiority of some chickpea cultivars in this study in terms of both grain yield and yield stability, in 2 temperate and cold regions in terms of stability and high grain yield, these cultivars can be candidates to introduce the cultivar or be used as parents of crosses in future breeding programs of this plant.

Considering the requirement of the country to meet the nutritional needs of the society and the nutritional needs of the existing livestock in order to meet the nutritional needs, it is necessary to introduce cultivars that can be superior to the existing cultivars in terms of adaptability and stability in arid and semi-arid regions. The use of forage plants such as Grass pea can play an important role in crop rotation, soil protection, reducing weeds and diseases due to high adaptability to dry and semi-arid climates and high yield potential, nitrogen fixation, tolerance to drought and salinity. This research was carried out with the aim of evaluating the interaction effect of genotype × environment and the stability of forage and grain yield of Grass pea genotypes in different regions of the country.

This study was carried out with 16 advanced Grass pea lines in Gachsaran, Mehran, Shirvan Cherdavel and Kohdasht stations for three crop years in the form of a randomized complete block design with three replications. Each genotype was cultivated in 6 lines with a length of 7.03 meters and a distance of 0.25 cm from each other. After analyzing the composite variance for different years in different regions, mean comparison was done using the minimum significant difference method at 5% and 1% probability levels. To analys the stability and compatibility of lines, were used the stability methods of Francis and Kanenberg, Eberhut and Russell, Rick's equivalence, Shokla's stability variance, Plasted and Patterson's stability parameter, Finley and Wilkinson, Perkins and Jinks, Gang's total ranking, and the single-variable, non-parametric method, Nassar- Han and Tanazaro.

The results of composite variance analysis of forage yield and grain yield showed that the simple effect of year, genotype, location and the genotype × location interaction effect for both traits were statistically non-significant, and the interaction effect of year × genotype was significant for forage yield and non-significant for grain yield. It was meaningful. The three-way effect of year × location × genotype was not significant at statistical probability levels for forage; but it was significant for grain yield. The forage yield for kholer lines from 12839 kg ha-1 for line number 5 to 16680 kg ha-1 for genotype number 10 with 11.5% drop and 15% superiority compared to Naghadeh, respectively. Also, in terms of grain yield, Grass pea lines fluctuated from 1239 kg ha-1 for line No. 7 to 1723 kg ha-1 for Line No. 10 with a 2% drop and 36.3% superiority compared to Naghadeh. The results of the stability analysis of forage yield showed that in terms of the Coefficient of variation parameter, genotypes 16, 5 and 10, in terms of Phenyl Wilkinson genotypes 15, 2, 13, in terms of Shokla genotypes 14, 9, 6, and in terms of Rick's equivalence, genotypes 14, 9, 6, and 13 were the most stable genotypes. The analysis of grain yield stability by univariate method showed that in terms of Coefficient of variation, genotypes 11, 12, 3, in terms of Phenyl Wilkinson, genotypes 13, 12, 4, 5, 6, in terms of Shukla's, genotypes 7, 12, 5, 6, and in terms of Rick's equivalence, genotypes 7, 12, 5, 6, and 8 were determined to be the most stable Grass pea genotypes.

Based on the obtained results, in terms of forage yield lines No. 1, 10, 3, 9 and 15 and in terms of grain yield genotypes No. 12, 15, 8, 10 and 7 had high stability and yield compared to other genotypes. In general, considering all parameters of stability and compatibility, lines number 1, 10, 12, 15, 8, 7 and 9 were selected as the most stable lines, and genotypes No. 10 and 15 were suitable for both forage and seed.

Medicinal plants are a rich source of bioactive compounds, and these plants are thought to be safe to human beings and the environment compared to the synthetic medicines for the treatment of many diseases. The active principles of the plants are generally secondary metabolites. Cumin (Cuminum cyminum L.) is an herbaceous and annual medicinal plant belonging to Apiaceae family which is planted in arid and semi-arid regions of Iran. Persian shallot (Allium altissimum Regel.) is another medicinal, industrial and perennial plant that has underground bulbs. It is one of the most important Allium species in Iran, which normally grows in semi-cold to very cold highlands. In the last decade, agricultural production, which is mainly based on the application of chemical inputs, is causing environmental impacts. The use of ecological farming approaches, enhancing yield and quality, they will be effective. Intercropping allows for improved resource use efficiency such as light, water and nutrients and beneficial interactions between the companion plants. It works to decrease the spread of plant diseases by reducing the quantity of susceptible host plants. Other benefits of intercropping include optimal use of resources, stabilization of yield, weed control, improved soil fertility, and higher economic returns. This study has evaluated the effect of intercropping ratios as replacement series of cumin and Persian shallot on agronomic criteria such as yield components, yield, harvest index, dry matter accumulation and land equivalent ratio.

This experiment was conducted based on a randomized complete block design with three replications at the Agricultural Research Station, College of Agriculture, Ferdowsi University of Mashhad during growing season of 2014-2015. Intercropping ratios as replacement series such as 80% cumin+20% Persian shallot, 60% cumin+40% Persian shallot, 50% cumin+50% Persian shallot, 40% cumin+60% Persian shallot, 20% cumin+80% Persian shallot and their pure culture were considered as treatments. Plant density for Persian shallot bulbs and cumin seeds were considered as 10 bulbs.m-2 and 120 plants.m-2, respectively. Studied traits were umbel numbers per plant, seed numbers per umbel, 1000-seed weight, biological yield and seed yield of cumin and daughter bulb diameter, mother bulb diameter, fresh weight of daughter bulb, fresh weight of mother bulb, biological yield, fresh yield of bulb, dry weight of bulb of Persian shallot and land equivalent ratio (LER).The LER was computed through the following equation:Where, Yij: Yield of cumin under intercropping conditions, Yji: Yield of Persian shallot under intercropping conditions, Yii: Yield of cumin under sole crop conditions and Yjj: Yield of Persian shallot under sole crop conditions. The treatments were run as an analysis of variance (ANOVA) to determine if significant differences existed among means. Multiple comparison tests were conducted for significant effects using the LSD test.

The results showed that the effect of intercropping ratios was significant (p≤0.05) on yield and yield components of cumin and Persian shallot. By decreasing intercropping ratios of Persian shallot improved its criteria. Diameter of mother bulb and production of daughter bulb in intercropping ratios were increased up to 52 and 68% compared to sole culture, respectively. Studied traits of cumin were improved by changing in planting ratios from intercropping to its pure culture. The maximum amounts of dry bulb weight were related to pure culture (82.9 g.m-2) and 20% cumin+80% Persian shallot (85.3 g.m-2). The highest seed yield of cumin was observed in pure culture with 115 g.m-2. The highest and the lowest LER were computed in 50% cumin+50% Persian shallot (1.49) and 80% cumin+20% Persian shallot (1.15).

Intercropping of Persian shallot and cumin had significantly effect on their yield and yield components. The results confirmed the better use of resources especially for radiation and water of these plants in intercropping ratios. In general, it seems that intercropping may be suitable cropping approach for sustainable production of medicinal plants. Acknowledgement This research was funded by Vice Chancellor for Research of Ferdowsi University of Mashhad, which is hereby acknowledged.

Due to the high importance of fenugreek in terms of nutritional and medicine, improvement of genotypes with high yield seems to be essential. Yield is a quantitative trait that is affected by the genotype-environment interaction. In order to evaluate stability and adaptation for seed yield in fenugreek ecotypes, the experiment was carried out during growing season for three consecutive years 2011-2013 in Jiroft Station of Research and Technology Institute of Plant Production (RTIPP) of Shahid Bahonar University of Kerman. Fenugreek ecotypes including Kerman, Kordestan, Mazandaran, Ilam, Kohgiluyeh and Esfahan were studied in different environments which a number of variables iron, zinc and three different irrigation intervals in randomized complete block design with three replications were considered. Combined Analysis of Variance (ANOVA) revealed genotype × environment interaction was significant for seed yield. Stability parameters including environmental variance (S2i), genotypic variation coefficient (CVi), Wricke's ecovalence, Shukla's stability variance and Eberhart-Russel Regression parameters were applied to study stability for yield. According to the results of Eberhart-Russel based on linear regression coefficients and deviation from linear regression, Kordestan ecotype with higher seed yield than the average, linear regression coefficient equal one (bi=1), as well as lowest deviation from the regression was identified as the most stable high performance genotype, while Kerman ecotype with higher regression coefficient than one (bi>1) and the highest yield was categorized as the most unstable genotype. Moreover, based on the other parameters, Kordestan and Mazandaran ecotypes were introduced as the most stable genotypes and Kerman ecotype as the most unstable genotype. Ilam ecotype was identified with general adaptation and low performance while Esfahan ecotype showed specific adaptation for the unfavorable environments.

Evaluation of varieties and soybean lines under drought stress helps to breeders for detecting of stable and high-yielding genotypes. In this regard an experiment was conducted in randomized complete block design with three replications under normal and drought stress conditions across two locations (four environments). The results of combined analysis of grain yield/plant revealed effects of stress, location and genotype, interaction of stress × location, genotype × stress, genotype × location and genotype × stress × location were significant. In the present study was used GGE biplot method for assessment of 121 varieties and advanced lines of soybean across four environments. The results of biplot method showed that first and second components explained 66 and 22 percent (in total 88 percent) of total variation respectively. That is showing relatively good reliability in explanation of G variation. The results of graphical method showed Gonbad environments (normal and stress) and Rasht environments (normal and stress) were different each other in ranking and determine of adaption. In investigation of polygon biplot was observed in Rasht location under drought stress condition (RD), Gonbad location under normal condition (GN) and Gonbad location under drought condition (GD) genotypes 37 and 34 had the highest yield. In addition these three environments can be considered as one Mega-Environment. Several genotypes were located in sectors that no environments were placed. These genotypes had low yield in most environments. In stability ranking graph, genotypes 8, 9, 49, 63, 42, 86, 39 and 46 had moderate yield and high adaption and those had suitable combination of stability (adaptation) and yield.

Genotype ´ environment interaction is one of the most important concepts in plant breeding which can be estimated using diffrerent statistical procedures. In this study, seed yield stability of 22 oilseed rape genotypes under normal and late sowing dates was evaluated during three cropping seasons (2011-14) in West-Islammabad filed station, Kermanshah, Iran. Results of combined analysis of variance showed significant differences between environments, among genotype, as well as genotype ´ environment interaction. Results also indicated that genotypes such as Hyola308, Zarfam, Shiralee, MHA01/18, Elite, Parade and Opera produced higher seed yield with 4487, 4475, 4442, 4408, 4350, 4333 and 4257 kg.ha-1, respectively. Results of AMMI analysis showed that four principal components of genotype ´ environment were significant at the 1% probability level. Proportional of sum of squares for the four principal components genotype ´ environment were 40.7, 28.5, 17.1 and 12.1 percent, respectively. Based on the first two principal components of genotype ´ environment, Parade, Kimberly, Elect, Goliath, Elite and Shiralee were positioned next to the center of biplot which implies high wide-adaptation. Simultaneous selection for stability and seed yield identified Shiralee, Hyola308, Zarfam, Parade, MHA01/18 and Kristina as high yielding and stable genotypes.

In order to decrease effect of genotype × environment interaction, yield and yield stability should be considered simultaneously. In present study, 24 bread wheat genotypes were evaluated in Gorgan and Gonbad agricultural stations in 2012-13 and 2013-14 cropping seasons. Experiments were conducted based on complete block designs with three replications at 6th December and February. Combined analyses of variance confirmed that the effects of year, location, genotype, year × genotype, location × genotype and year × location × genotype interactions were statistically significant (P

Vascular wilt fungus, Verticillium dahliae, and root knot nematode, Meloidogyne incognita, are the most common and destructive pathogen factors in cotton. In order to study interactions between these two factors, their interaction effect on 4 cotton cultivars (Sahel, N200, Mehr and Varamin) was done in a completely randomized block design in 4 iterctions and 6 treatments in a greenhouse. Treatments including, control, just fungus, just nematode with concentration of 2300, just nematode with concentration of 7000, both fungus and nematode with concentration of 2300 and both fungus and nematode with concentration of 7000. 12×104 Microsclerote for each fungus treatment and 7000 and 2300 nematode eggs and second stage juvenile for the nematode treatments respectively (depending on the desired treatment) were inoculated to 60 days old cotton seedling. Meloidogyne incognita nematode was isolated from the host plant and then its species and race were determined and at last it was reproduced by inoculation to tomato transplants. After that the Verticillium dahliae fungus was isolated from infected cotton plants and after cultivation and identification steps, it was transfered to the Tajan wheat seed cultivar (three times been autoclaved) for reproducing.The results of this review after 2 months showed that the interactions between Verticillium dahliae fungus and Meloidogyne incognita nematode in cotton was resonator. As a combination of fungus and nematode simultaneously leads to a significant increase (P =%1) in the wiltdejection. With increment in nematode concentration, root rot, the number of nodes and egg mass increased and shoot and root length, fresh and dry weight decreased vice versa.

In order to determine of potential forage productivity of cold – region alfalfa ecotypes and introduce superior ecotype for each location، this experiment was conducted with 17 ecotypes in Randomized Complete Block Design (RCBD) with three replication in 5 locations include Karaj، Esfahan، Tabriz، Mashad and Hamedan for 4 years during 2004-2008. Significant differences were found among total mean of fresh، dry forage yield، plant height in harvesting and leaf to stem ratio among tested locations. However، ecotypes have significant differences for fresh and dry forage yield. Also for all traits except dry forage yield، significant differences were found among three years. Interaction effects were significant especially for yields. Regarding to results، Esfahan with 124. 76 and 27. 25T/ha for fresh and dry forage yield was the best location corresponding to forage productivity. Three superior ecotypes corresponding to fresh and dry forage yield، plant height and leaf to stem ratio in all locations and years were as follows: Silvana، Galebani and Rahnani with 67. 63، 67. 22 and 66. 98 T/ha for fresh forage yield، Ghahavand، Kozareh and Silvana with 18. 69، 18. 47 and 18. 44 T/ ha for dry forage yield، Galebani، Silvana and Sahandava with 72. 06، 70. 00 and 69. 70 centimeter for plant height in harvesting and Silvana، Sahandava and Malek-kandi with 1. 04، 1. 02 and 1. 02 for leaf to stem ratio respectively.

In order to study effect of G×E interaction on yield of genotypes in three environment. These genotypes were planted using RCB design with 3 replications in Esfahan, Kermanshah and Varamin. The results of combined analysis of variance for yield showed significant difference for genotype, location and G×E interaction effects. Because of significant G×E interaction stability analysis methods AMMI were used for determination of desirable genotypes for yield. Based on AMMI method, genotypes No. 5, 6, 11, 15, 16 and Marvdasht variety showed general adaptability and genotypes 17 and 18 recognized to have specific adaptability to Varamin and genotypes No. 4, 19 and 20 had specific adaptability to Kermanshah. Overall, based on stability analysis on yield genotypes No. 15, 16 and Marvdasht with having good adaptability were determined as desirable genotypes.

To evaluate the competition between wheat and wild mustard (Sinapis arvensis) in nitrogen and herbicide levels, an experiment was conducted in Ramin Agriculture and Natural Resources University, at 2007-8. A split-plots design in RCBD (Randomized Complete Blocks Design) with three replications was used for this experiment. The nitrogen levels (0, 60, 120 and 180kg/ha) arranged in main plots. Each main plot was be splitted to five sub-plots, and herbicide levels (0, 15, 20 and 25g three benoron methyl/ha) with hand-weeding as a control treatments were arranged in sub-plots. The results showed that the interaction effect between nitrogen and herbicide levels on grain yield (GY) of wheat and dry matter (DM) production of wild mustard was significant. With increase of nitrogen, while herbicide levels were low or no control was be done, GY of wheat and DM of wild mustard decreased and increased, respectively. It can be said that in high levels of nitrogen, more herbicide will be required for weed management. In low levels of nitrogen, difference between herbicide levels was little and DM of wild mustard decreased significantly. Generally, increase of nitrogen caused to decrease of wheat competition ability against wild mustard and also caused to requirement more herbicide. Highest DM of mustard was produced with 180kg N/ha without weed control. In the other hand, highest GY of wheat was gained by 180kg N/ha and 20g three benoron methyl/ha.

This research was conducted to investigate genotyp×environment interaction for grain yield of ten wheat cultivars in 8 environments (combinations of two nitrogen fertilizer treatment and four irrigation regimes). Analysis of additive main effects (analysis of variance) and multiplicative interaction effects (principal component analysis) revealed that the effects of genotype, environment and genotype ×environment interaction were highly significant. three first principal components explained 89% of the interaction sum squares. Biplot of the first principal component and mean grain yields for genotypes and environments revealed that high yielding genotypes of Pishtaz and Moghan1 were more stable cultivars. Pattern analysis of two first significant principal components for genotypes and environments and also cluster analysis based on stability statistics of AMMI3 model (SIPC3 and EV3) showed that Pishtaz genotype had general stability. The grain yield of this cultivar was higher than the average of all genotypes, it was implied that this cultivar had general adaptability. Khazar cultivar was ranked as the second stable cultivar with having grain yield of approximately as much as the average of all genotypes; thus it was considered as a genotype with moderate general adaptability. Cultivars of Alvand, Sabalan, Moghan1, Darab and Falat showed very low stability. Sardary and Omid with lower yield were recognized as unstable cultivars. Also, it was found that all environments had contribution in the interaction effects.

This study was conducted to investigate the genotype¬×¬environment interaction effects on yield and yield components of wheat. Ten cultivars of wheat were evaluated in 8 environments (combinations of two levels of nitrogen and four irrigation regimes) in growing season of 2006-2007 at the Research Farm of Isfahan University of Technology. Based on the stability parameters of Eberhart and Russel, Pishtaz and Moghan1 that had higher yield than the average and regression coefficient of 1 (approximately), were more adapted cultivars. However, Khazar and Alvand cultivars showed specific adaptation to better and Falat, Darab and Roshan cultivars to poor environments. Path analysis of genotype¬×¬environment interaction (Tai's method) showed v1 component that indicated the correlation of fertile panicles/m2 with grain yield, was high and significant only for unstable cultivars, therefore, this component is not a suitable criterion for selection of stability. The environmental components showed that fertility and grain filling periods were the most sensitive growth stages of cultivars to the environmental conditions, therefore, it seems that selection for stability based on this component (v2) may not be effective. Genotypic component of v3 (seed weight) was the most effective component of yield stability and based on this component, Pishtaz was the highest yielding and stable cultivar. In general, according to the results of this study, Pishtaz with grain yields of 9.27 t/ha and with the highest stability was determined as the suitable cultivar.

Cucurbit wilt caused by Phytophthora drechsleri is one of the most important diseases in Varamin and Garmsar areas. Reduction of yield of cucurbit by this disease has been reported about 25%. Soil salinity which can cause the important damage to the plant metabolism and nutrition, is common in these regions. Cucumber is susceptible to salinity stress. Therefore salinity stress may increase the susceptibility of cucumber to Phytophthora drechsleri. Different levels of salinity (control, 0, 10, 25 and 50 mM NaCl) on three current cultivars (Tezier, Super 2000 and U. S. A.) of cucumber were investigated at the presence of P. drechsleri in greenhouse conditions. A factorial analysis for completely randomized design with 3 replications, was used for these experiments. Significant differences were observed among the different levels of salinity. Increasing stress due to salinity increased the susceptibility to the disease. Cucumber cultivars had different responses to salinity. The effects of different levels of salinity (0, 10, 25, 50 and 75 mM NaCl/l) were also investigated on growth of P. drechsleri on CMA culture at a completely randomized design with 3 replications. Variance analysis of growth area of fungus on CMA culture showed significant differences among different levels of salinity. Growth area of fungus was 6359 mm2 for control and 4725 and 4797 mm2 for 50 and 75mM NaCl, respectively.