جستجوی مقالات مرتبط با کلیدواژه "تجزیه رگرسیون" در نشریات گروه "باغبانی"

This study was conducted in order to evaluate the variation of blackberry accession of Iran in terms of antioxidant activity, phenolic components, fruit quantitative traits and photosynthesis pigments. For this regards, four accessions of wild blackberry including Babolsar, Naharkhoran, BandarGaz and NamakAbroud belongs to Rubus sanctus species, which collected from the northern area of Iran and has been kept in Blackberry Collection of Horticulture Department of Shiraz University were selected and subjected to factorial design based on randomized complete block designs with four replications in two consecutive years. Then, the fruit sanmples were collected in three fruit maturity stages (Black, Red and Green). The results indicated significant differences between accessions in terms of half maximal inhibitory concentration (IC50) (range, 46.25-65.50 %), total phenolic content (TPC) (range, 224.67-350.53 mg/100 g DW), flavonoid (range, 531.71-812.37 mg/100 g DW), flavanone (range, 18.47-75.55 mg/100 g DW), anthocyanin (range, 92.23-281.57 mg/100 g FW) along with other traits. Furthermore, the highest quantity of abtioxidant and phenolic compounds were observed in complete fruit maturity stages (Black) compared to other maturity stages. There was a positive and significant association between antioxidant activity and phenolic compounds. Babolsar genotype with highest quantity of phenol (350.53 mg/100 g DW), anthocyanin (281.57 mg/100 g FW), flavanone (75.55 mg/100 g DW), flavonoids (812.37 mg/100 g DW) and lowest amount of IC50 (46.25 %) identified as the best genotype in terms of nutritional value.

The purpose of this study is surveying the genetic diversity between oilseed sunflower genotypes and relationships between traits and grain yield, so 12 genotypes cultivated in a completely randomized block design with three replications. Based on the results of analysis of variance, traits were observed among genotypes at a probability level of 1% for the traits of 100 seeds and at 5% probability for the traits of diameter and grain yield of diversity. The results of simple correlation coefficients of traits showed that the diameter of the plant had the highest correlation with plant height and 100 seed weight. The results of simple correlation coefficients of traits showed that the diameter of the plant had the highest correlation with plant height and 100 seed weight. The results of path analysis showed that the highest direct effect on seed yield was observed on seed width and plant height. Using factor analysis by principal component analysis, four factors justify 82.5% of the data variation. The first factor justified 34.2% of the total variance of the data, that named seed yield, the second factor justifying 21.9% of the variation factor that named length factor ,the third factor, justifying 14.5% of the data changes as the factor of 100-grain weight and the fourth factor justified 11.7% of the total data variance, was named dimeter factor.

The present study was aimed to investigate the response of the growth and physiological parameters of stevia (Stevia rebaudiana Bertoni) medicinal plant to salinity stress using a pot experiment in 2014. Ten levels of salt stress (0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 mM of NaCl) were arranged in randomized complete block design with three replicates. Regression analysis of data indicated that some measured parameters such as stem diameter, plant height, green leaf number in plant, relative water content (RWC), chlorophyll a, b, leaf greening (SPAD value), leaf fresh weight, root and shoot dry weights linearly decreased when NaCl amount increased in the growing media. Green leaf number in plant and leaf greening (SPAD value) were more sensitive than other mentioned parameters. However, the response of some determined parameters such as electrolyte leakage, chlorophyll a/b ratio, stem, root, shoot and total fresh weights along with leaf, stem and shoot fresh weights were described by a segmented model. In conclusion, stevia plant could tolerate salt stress up to 80 mM and then its growth and physiological parameters significantly and adversely affected. Results, also, revealed that physiological parameters were more sensitive to salt stress than morphological parameters.

Stability analysis and genotype by environment interactions for production and release of varieties is very important. For this purpose, twelve genotypes of sunflower in five stations including Arak, Birjand, Shiraz, Kashmar and Karaj base randomized complete block design with three replications during 1394 were planting and evaluated. After analysis of variance and significant yield effects of environment and genotype by environment interaction, for stability analysis from univariate methods based analysis of variance and regression analysis were used. Based on the Shukla stability variance statistics and Rick ecovalance, Favorit and Progress genotypes had higher stability. Francis and Kananberg environmental coefficient variation, the Lin and Binns variance and Romer environmental variance showed that Master and Sor genotypes had higher performance than the average and had the higher stability than other genotypes. According to Eberhart and Russell, Master and Sor genotypes with high yield and nonsignificant regression coefficients were identified as stable genotypes for all areas. Zargol genotypes with high performance and a significant regression coefficient that suggests high genotype-environment interaction in this genotype and were the reason for the specific adaptation of this genotype with adequate environment, and with better conditions shows high performance.

This experiment was conducted to investigate the genetic diversity، relationship between morphological، agronomic and qualitative traits and to identify components of forage yield using some multivariate statistical methods in local sainfoin populations. The experiment was conducted as randomized complete block design with three replications in Agricultural and Natural Resources Research Center of West Azerbaijan. Results indicated that correlation coefficients of forage yield with number of branches per main stem، number of leave and number of stem were significantly positive but with harvest index leaf and degree day emergence was significantly negative. Forage yield had no correlation with plant height but plant height was correlated with number of leave. Principal component analysis revealed six component which justified more than 76 percent of the total variation، and classified as “Yield”، “Dry weight”، “Plant size”، “Harvest index leaf”، “Morphological-phenological traits” and “Flowering rate”، respectively. On the basis of stepwise regression analysis، number of stem، plant height and number of leave justified the majority of hay yield variation. Hence، these characters could be use for selecting high yield cultivars. Thus، direct effect of these three traits on forage yield were calculated 0/726، 0/226 and -0/984 respectively by Path analysis. Finally، on the basis of the current result in this research compared with previous findings، it can be concluded that multivariate statistical methods can be useful to find relationships between quantitative characters in sainfoin.

Wheat (Triticum aestivum L.) is a major staple food crop for more than one third of the world population and is the main staple food of Asia. Over 800 million hectares of land throughout the world are salt affected. Salinity is a major obstacle to food production because it substantially reduces the average yield of major crops. This study was conducted to evaluate the response of 24 cultivars and genotypes of wheat (Triticum aestivum L.) to NaCl salinity at early seedling growth and correlation between affected morphophysiological traits and molecular markers. Genotypes grew in hydroponic nutrient solution, under control (tap water) and salt stress (45 and 90 mM NaCl) conditions. Results of ANOVA analysis showed that there are significant difference (in one percent P-value) between genotypes and all of measured traits in different levels of salinity. A total of 20 RAPD and 34 ISSR primers were tested to investigate genetic diversity in 24 wheat genotypes. Of these, only 15 ISSR and 6 RAPD primers produced polymorphic bands and were further used for genetic diversity and regression analysis. Cluster analysis was performed based on jaccard coefficient and all genotypes were divided into 4 groups. Average genetic distance between genotypes was 0.486, showed that there is considerable variation among these genotypes. Regression analysis, also, revealed that there are significant relations between measured traits and using markers were investigated.

In order to evaluation of the relationship among protein markers and traits such as proline content variation، quantum efficiency of photosystem II and field viability index، 20 genotypes of barely were studied in a randomized complete block design in the greenhouse experiment. Plants were transferred to springhouse at the four leaf stage and were located at the temperature of 4°C for three weeks. The leaves were sampled، before and after the adaptation phase، to measure proline amount and quantum efficiency of photosystem II (Fv/Fm). Then freezing treatments were applied by temperatures of -4، -7، -10، -13 and -16. Also، these genotypes were planted in the field to determine the parameters of LT50 and FSI. According to our findings، some significant relations between protein markers and freezing resistance in hordeum vulgar was determined. According to A-PAGE technique، The obtained results showed decreasing trends in quantum efficiency of photosystem II، respectively، during adaptation phase. It was found significantly negative correlations between FSI and LT50 (-0. 601). Cluster analysis classified by FSI، LT50، proline، Fv/Fm، the genotypes of F-A1-1، F-A1-2، F-A2-11 and F-GRB-85-5 and cultivars of Sahra، Sahand، Dasht and Makooii were located in group that had a high value of FSI and LT50. In this recearch، Makooii knowened as the most resistant veriety because of LT50= -17. 66 and high FSI value. Based on regression analysis، there are relationship among four markers and LT50. Our results showed that we can introduce these markers as selection of the resistant lines.