جستجوی مقالات مرتبط با کلیدواژه « تجزیه چند متغیره » در نشریات گروه « زراعت »

Rapeseed is a main oilseed crop in the world. Water deficiency is the main cause of reduced crop yield under drought stress. The highest rapeseed yield reduce was resulted when water deficit occurred at flowering and pod developmental stages (Kahrizi and Allahvarand, 2012). Knowing about the traits that affect grain yield, so that by improving these traits, grain yield can be increased, plays an important role for being successful breeding programs. Factor analysis of multivariate statistical methods is for a deeper understanding of the relationships between traits and is an effective statistical method in reducing data volume (Cooper, 1983). The aim of this study was to study the effect of late-season drought stress on some traits affecting the yield of studied rapeseed genotypes and to identify genotypes compatible with normal and drought stress conditions using some stress tolerance indices.

This experiment was carried out at the research field of Seed and Plant Improvement Institute, Karaj, Iran, on 2016-2018 growing seasons under full irrigation conditions and late-season drought stress (from beginning pod setting stage) on new winter rapeseed genotypes in a randomized complete block design with three replications. Some of morphological, physiological, phenological traits, yield and yield components were measured. Factor analysis was performed to determine the most influential variables. To identify drought tolerance genotypes, drought tolerance indices such as tolerance index (TOL), stress susceptibility index (SSI), mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HMP), stress tolerance index (STI), Yield index (YI), Sensitivity drought index (SDI) and yield stability index (YSI) were used.

The combined analysis of variance showed that the effect of drought stress on all evaluation traits was significant except for height of the first branch, days to end of flowering, flowering period and oil percentage. The results showed that drought stress decreased Grain yeald, Pods per plant, Seeds per pod, 1000 Seed weight, plant height, Chlorophyll a and b, Cartenoid, Relative water content and Days to maturity; while it increased Chlorophyll Index (SPAD).The results of factor analysis exhibited three factors in normal and drought stress conditions, which explained 79.7% and 82.51% of the variation, respectively. This factors in normal conditions were named "Yield", "Plant pigment", "Phenological traits" respectively, and in stress conditions were named " productivity", "Plant pigment" and " sink" , respectively. It seems that its seams possible to use these traits as selection criteria in breeding programs for improve grain yield of winter rapeseed genotypes results showed that GMP, MP, HMP and STI indices were positively correlated with grain yield under both stress and non-stress conditions. Therefore, they can be exploited not only to screen drought tolerance but also to identify superior genotypes for both stress and non-stress field conditions (Fernandez, 1992). Principal component analysis using grain yield under both conditions and drought tolerance indices showed that the genotypes Nafis, Vesuvio, Medea, HL3721 and HL2012 were the most tolerant genotypes to drought conditions, while the genotypes Extorm, Excalibur, Danube and Expower were the most sensitive genotypes. With cluster analysis using WARD procedure based on drought tolerance, the studied genotypes were grouped in 3 separate clusters. The first group consisted of genotypes that have high yield and drought tolerant and had appropriate and reliable values of indices such as STI, MP, GMP, HMP. Therefore, this group (genotypes Nafis, Vesuvio, Medea, HL3721 and HL2012) are drought tolerant group. The second group had genotypes with low values of STI, MP, GMP, HMP as well as Ys and Yp and higher values of SSI. Therefore, genotypes Danube, Excalibur, Expower, Harnus and Extorm with low yield and drought sensitivity were placed in this cluster. The next group (Okapi, Ahmadi, Nima, Natalie, SLM046, Artist) with average yield in both non-stress and stress conditions, and less sensitivity to drought stress condition, were stable in yield, and therefore considered as semi-resistant cultivars.

Barley is one of the most important crops in the world and ranks fourth in terms of nutritional importance and area under cultivation among cereals after wheat, corn and rice, but it has ranks first in terms of the extent of cultivation in a variety of climates. The world's food production is severely limited by environmental stresses. One way to sustain production for the world's growing population is to minimize the reduction in production caused by these tensions. Given that heat stress, in particular late season heat is the most widespread type of heat stress in the world, especially in the subtropical regions, and as a major constraint in the production of sustainable crop yields, including barley. Therefore, identifying heat-tolerant genotypes can be a valuable solution to this problem. The present experiment was undertaken to understand the impact of high temperature on yield and its attributing traits and to select heat stress tolerant parents and cross combinations for future breeding program.

To fulfill the requirement of this objective, the experiment was conducted in two environments i.e. normal and heat stress. Infact This study was performed to evaluate the heat tolerance at the end of the season and to identify barley tolerant genotypes using stress tolerance indices on experimental farm of the Gonbad Kavous University during the growing season of 2015-2016. The experimental plant materials were 120 barley genotypes which were evaluated in a randomized complete block design with two replications under two conditions without stress and heat stress. In addition, seeds of each genotype were grown in two meter rows with 20cm distance between the rows and the plant density was 270 plants per m-2.

The results of this experiment showed that the highest yield mean in non-stress conditions was related to genotype Torsh and in stress conditions was related to genotype Line143-2. The results of analysis of variance for yield trait showed that the differences between genotypes and the interactions of genotype and environment were significant at the level of one percent for the trait, which indicates high diversity and different reactions of cultivars and lines in different environments. Comparison of indices also showed that YI, STI, GMP and MP indices had the highest significant correlation with yield under non-stress and stress conditions and the superior indices of this experiment were for screening heat tolerant genotypes. Cluster analysis based on indices and yield under stress and non-stress conditions divided the studied genotypes into three groups.

Overall, the results of cluster analysis and principal component analysis showed that genotypes Torsh, Zarjo and 4Shori had the highest tolerance and genotypes Line105, Nosrat, Line98-2 and Fajr30 had the lowest tolerance to heat stress. Obviously, it is necessary to repeat the experiment in other places to be surer of these results and to obtain definitive results. On the other hand, to obtain heat-tolerant cultivars, it is recommended to cross the Torsh, Zarjo and 4Shori genotypes, and to locate heat-tolerant control genes, tolerant genotypes (Torsh and Zarjo) cross with sensitive genotypes (Line105 and Nosrat) can be used as two parents.

Improving knowledge on the relationships between agro-morphological traits in Chitti bean (Phaseolus vulgaris L.) will contribute to identifying key traits affecting grain yield for use in bean breeding programs. A field experiment was conducted using an augmented design consisting of 116 breeding lines and three checks (Sadri, Kousha, Khomein local). Statistical analysis showed that grain yield and seeds per plant had the largest variations. Regression analysis showed that days to emergence of the first trifoliate leaf (V3), seeds per pod, and plant height, explained more than 39 percent of the variation in grain yield. Path analysis indicated a high negative direct effect of V3 and a positive direct effect of seeds per pod on grain yield. Cluster analysis helped to classify all genotypes into four distinct groups. From the genotypes studied, 38 superior genotypes were selected, which can be used in the breeding programs of Chitti bean Also, number of days to emergence of the first trifoliate leaf and the number of seeds per pod were identified as traits useful to consider in bean breeding programs aiming at improving the grain yield of Chitti beans.

In this research, the genetic diversity of some oriental and water pipe’s tobacco genotypes was investigated under normal (without Orobanche) and Orobanche stress conditions during 2007-2008 and 2008-2009 at Urmia Tobacco Research Centre with randomized complete block design with three replications. Combined analysis of variance revealed extent genetic variability among the genotypes for most of the studied traits. This suggests that there is high genetic variability among tobacco genotypes for resistance to Orobanche which can be effectively used in biotic resistance breeding programs. A high genotypic coefficient of variation was seen for studied traits especially for FWL and DLYP in normal and Orobanche stress conditions. The highest broad-sense heritability was estimated for FD, NL and PH in both normal and Orobanche stress conditions. The results of the genetic advance calculation showed that the highest genetic advance was related to LAI, APFW, PH and FWL traits. Based on the results of genetic correlation coefficients of traits, positive and significant genetic correlations were observed between DLYP with all studied traits in both normal and Orobanche stress conditions. Cluster analysis classified all tobacco genotypes into four clusters under normal and stress conditions. In Orobanche stress condition, ratings the clusters in view of traits average showed that the second and fourth clusters contain genotypes that are resistant and sensitive to Orobanche stress, respectively. Therefore, by selecting suitable parents from these groups and crossing them, it will be possible to produce segregated populations in Orobanche resistance breeding programs and to make desirable changes in tobacco yield. Results of cluster analysis were confirmed by results of canonical discriminant function results. The principal component analysis identified two components in each condition which explained more than 75 and 73 percent of the total variation in normal and stress conditions, respectively. Genotypes classified in the second cluster can be potentially used in the Orobanche infested areas.

To evaluate genetic diversity of Kabuli chickpea genotypes under rainfed conditions in Entezary planting, an experiment was carried out in a randomized complete block design with two replications, in innovation platform of Iran-ICARDA Food Security Project located in Kamyaran city (Kurdistan province) during the year of 2016-2017. Based on the factor analysis, four factors were selected which 85.7 percent of the total variation were explained. The first factor was explained 29 percent of variation which include plant height, the first pod height, the last pod height and 100 grain weight. The second factor was explained 28.5 percent of variation which include number of pod per plant, number of seed per plant and grain yield. Therefor these two factors used to identify genotypes with high yield and yield components and genotypes 3, 4, 14, 15 and 16 were selected as high yield and yield component genotypes in Entezari planting. According to the result of cluster analysis based on morphological traits, the genotypes were classified into three groups. The genotypes of the first and the third clusters in most of agronomic traits and grain yield per plant had high average, compared to other clusters and genotypes average. According to the results of cluster analysis, we can use from genotypes of the first and the third clusters for producing hybrids with early maturity and high grain yield.

Salinity is one of the most important environmental stresses that can affect crop production. The research aimed to study the genetic diversity of 20 wheat varieties at Islamic Azad university, Ahvaz branch in 2015 in factorial experiment in basis randomized completely blocks design with 3 replications of 20 varieties as the first factor and salinity stress with NaCl at 4 levels of zero (distilled water), 4, 8 and 12 ds/m as the second factor was implemented. The principal components analysis, 11 studied traits is divided into 2 components on the basis of 57% of the data changes can be justified. The first and second components respectively 39.7% and 16.9% of the total variation stated and respectively are tolerant and sensitive to salinity were named. Using cluster analysis of 20 varieties located in three clusters. Varieties of Arg, Listan, Bahar, Maron and Hirmand were in the second cluster and the percent of emergence, length of seedling, dry weight of seedling, seed vigor index, leaf relative water content, K concentration, K/Na ratio, STI based dry weight of seedling and length of seedling were higher than the overall mean and it is worth noting that these characteristics in high salinity conditions are favorable. As well as the ionic leakage and Na concentration less than the overall mean that it is desirable in terms of salinity tolerance. According to this study, the use of this varieties for future breeding programs are recommended for salinity tolerance.

The research aimed to study the genetic diversity of 26 rice genotypes in 2013 at the Research Center for Agriculture and Natural Resources Khuzestan province factorial experiment in basis completely randomized design with 3 replications of 24 lines and 2 hybrid as the first factor and salinity stress with NaCl at 4 levels of zero (distilled water), 4, 8 and 12 mmoh/cm as the second factor was implemented. Traits of germination percent, mean germination time, germination rate, radicle length, plumule length, seedling length, ratio of radicle length to plumule, wet weight of seedling, dry weight of seedling, ratio of dry weight to wet and index seed vigor were studied. The principal components analysis, 11 studied traits is divided into 2 components on the basis of 64% of the data changes can be justified. Using cluster analysis were 26 genotypes in three clusters. Lines 15, 19, 20, 48 and 53, according to the results of cluster analysis and biplot rate germination, plumule length, radicle length, seedling length, weight and vigor index lower were. The third cluster lines do not have the tolerance to salinity. Lines 2, 4, 7, 10, 13, 16, 21, 23, 25, 28, 31, 34, 35, 36, 41, 42, 44, 55, with hybrids and Hb2 in the cluster were Hb1 according to principal component analysis and biplot half are salt tolerant. Line 40 was alone in the cluster according to the results of cluster analysis and biplot all traits germination, plumule length, radicle length, seedling length, radicle to plumule ratio, wet weight, dry weight, dry weight and seed vigor was higher than the overall mean and so is salt tolerant.

Confectionery sunflower (Helianthus annuus L.) is one of the valuable crops which less is known about its variability. Fifty sunflower populations have been gathered from different regions of Iran and evaluated for agro-morphological traits in completely randomized design with 10 repetitions under pot conditions. The twenty traits including days from planting to flowering¡ days from planting to physiological maturity¡ number of leaves¡ leaf length¡ petiole length¡ leaf width¡ plant height¡ stem diameter¡ head diameter¡ shoot dried weight¡ head dried weight¡ aerial part dried weight¡ harvest index¡ 100-seed weight¡ single seed weight¡ dehulled kernel weight¡ dehulled kernel weight to whole kernel¡ seed length¡ seed width¡ and seed dried weight per plant were evaluated. Analysis of variance showed that there is a meaningful difference between all traits except for single seed weight and stem diameter. The highest positive correlation (0.95) was observed between single seed weight and dehulled kernel weight and the highest negative one (-0.61) was observed between number of leaves and harvest index. Principal component analysis decreased the studied variables to six components with the cumulative variance of 81%. Cluster analysis with Ward method classified them into four different groups. The maximum distance was observed between genotypes of groups 1 and 4 as well as 3 and 4. The comparison of trait means in groups resulted from cluster analysis by Tukey’s test demonstrated that the populations in the first group have the maximum values for most of the studied traits and populations in the fourth group have the minimum values and therefore they can be used for choosing appropriate parents in crossing programs.

Sunflower as an annual crop is being cultivated for nut and oil usages. Having different morphological and physiological traits، the yield of different cultivars and genotypes are varied. The selection of favorable genotypes using morphological markers for the aim of increasing yield have been effective and achieved to the trade benefit of sunflower. In present work، morphological characteristics effective on the yield of 22 genotypes of oil sunflowers، were studied in a randomized complete block design in four replications. The comparison of treatment means showed that cultivar Record had the highest yield of seed and oil. Simple correlation between characteristics coefficients confirmed the direct relationship of seed yield with oil yield and the number of seeds per cap. Stepwise regression analysis followed by path analysis exhibited the number of seeds and weight of thousand seeds as important traits effective on seed and oil yield، and revealed their direct and indirect effects. In factor analysis based on maximum likelihood، five factors were extracted. Cluster analysis categorized the genotypes to five groups based on the yield mean of the studied traits using Ward method.

To study relationships between effective traits on wheat grain yield، the varieties Zarrin and Alvand، and some promising lines i. e. C-81-4، C-81-10، C-81-14 and C-82-12 were investigated at three sowing dates including 10 October، 1 November and 21 November. The experiment was carried out using strip plot in RCBD with three replications under two different water conditions including full-irrigation and terminal water stress at Miyandoab Agricultural Research Station in 2005-06 and 2006-07 cropping seasons. The results showed that under both full irrigation and terminal water stress conditions، grain yield had positive and significant correlation with days to heading، days to maturity، plant height، number of spikes/m2 and 1000 grain weight. Stepwise regression analysis revealed that 83 percent of yield variation under non-stressed conditions could be determined by days to maturity and number of spikes/m2 (R2 = 83%) whereas these traits explained 87% of yield variation under stress conditions (R2= 87%). Path analysis indicated that number of spikes/m2 and days to maturity had the greatest positive direct and indirect effect on grain yield، under both conditions. The results of factor analysis under non-stressed condition showed that three factors explained 77% of total variation; these factors were called grain yield components، grain characteristics and plant phonology. Under non-stressed condition two factors (that were called grain yield and phenology، and plant morphology) explained 88% of total variation. Cluster analysis through ward method، classified days to maturity and number of spikes/m2 in the same cluster where the grain yield was put under both conditions. It was concluded that under different sowing dates، selection based on days to maturity and number spikes/m2 could indirectly led to higher yield under both normal and water stress conditions.

Various assessment take place for realize genetic variation identification. In this Experiment 27 lines from common bean (Phaseolus vulgaris L.)، one local 2 Talash and cos-16، cultivars were sown using. randomized complete block design with 3 replications in Farm of university of Zanjan in 2008. Results of analysis of variance showed significant differences among entries for chlorophyll content index، leaf area index (LAI)، biological yield and grain yield (P<0. 01) and trait protein% (P<0. 05). There was agreement in grouping results of cluster analysis and principle component analysis. The first three components determined 65% of the total variation، For the first component، special leaf weight (SLW)، leaf area ratio (LAR) and grain yield justified the most variance. For the second components، leaf area index، chlorophyll content index and for the third components، leaf weight ratio in podding stage and percent protein showed the most variation. It was concluded that lines number 20 and 3 had higher values for boty grain yield and protein% than other entries.

This research was conducted in order to have genetic evaluation of some important agronomic traits as related to seed yield، using 20 soybean varieties in randomized complete block design with three replicates at Agricultural Experiment station، college of Agriculture، karaj.، Iran. A total 20 traits related to vegetative and reproductive growth and yield component were analysied. Analysis of variance showed that there were significant differences among varieties in terms of traits under study، indicating the existence of genetic variation among varieties. Duration of seed filling and pod length had highest and yield had the lowest broad sense. Among the desired traits، 100-seed weight، number of seed / plant and number of seeds/pod، all of which are considered yield component، had the highest correlantion with plant yield. Using multiple linear regression model for 20 traits under study، showed 93% of total variation in yield plants، were attributed to three traits: Namely 100 seed weight، number seed/plant and seed width. Result of path analysis showed the highest and the lowest direct effect، being positive، were related to number of seed/plant and seed width، respectively. Results of factor analysis showed the important factor، called yield component. This factor explained 17/3% of total variation in data.

To study the relationship between some quantitative and qualitative traits in red bean, 15 red bean genotypes were studied in experimental field of Faculty of agriculture, the University of Tehran in 2004 cropping season using a randomized complete block design with three replications. Necessary scores and measurements were made and multivariate statistical analyses were performed for different quantitative and qualitative traits. Analysis of variance of data revealed high genetic variation for concerned traits among red bean genotypes. Seven quantitative traits were used in stepwise regression model which included quantitative attributes of seed and plant morphological traits. Among these attributes pod weight in plant and length of internode with highest correlation coefficients had direct effects of 1.605 and -1.302, respectively. In factor analysis, 89% of total variation was explained by eight factors which were divided in two sets: The primary factors included; seed yield related; quantitative morphological and physiological traits and the secondary factors comprised; cooking quality related traits and plant type. Cluster analysis grouped the 15 red bean genotypes in three distinctive groups. KS31169 genotype had the least similarities with the other genotypes; therefore, it would be expected that crosses made between this genotype and genotypes of the first group will develop desirable variation in segregating populations for breeders.