Multivariate analysis and determination of the best indirect selection criteria to genetic improvement the biological nitrogen fixation ability in common bean genotypes (Phaseolus vulgaris L.)

In order to determine the best indirect selection criteria for genetic improvement of biological nitrogen fixation, sixty four common bean genotypes were cultivated in two randomized complete block design. Genotypes were inoculated with bacteria Rhizobium legominosarum biovar Phaseoli isolate L-109 only in one of the experiments. The second experiment was considered as check for the first. Correlation analysis showed positive and highly significant correlation of majority of the traits with percent of nitrogen fixation. Step-wise regression designated that traits percent of total nitrogen of shoot, number of nodule per plant and biological yield accounted for 92.3 percent of variation exist in percent of nitrogen fixation. Path analysis indicated that these traits have direct and positive effect on percent of nitrogen fixation. Hence, these traits are promising indirect selection criteria for genetic improvement of nitrogen fixation capability in common bean genotypes especially in early generations

Genetic control and combining ability of flag leaf area and relative water content traits of bread wheat cultivars under drought stress condition

In order to compare mode of inheritance, combining ability, heterosis and gene action in genetic control of traits flag leaf area, relative water content and grain filling rate of bread wheat under drought stress, a study was conducted on 8 cultivars using of Griffing’s method2 in fixed model. Mean square of general combining ability was significant also for all traits and mean square of specific combining ability was significant also for all traits except relative water content of leaf which show importance of both additive and dominant effects of genes in heredity of these traits under stress. GCA to SCA mean square ratio was significant for none of traits. Results of this study showed that non additive effects of genes were more important than additive effect for all traits. According to results we can understand that genetic improvement of mentioned traits will have low genetic efficiency by selection from the best crosses of early generations. Then it is better to delay selection until advanced generations and increase in heritability of these traits

Genetic Improvement of Biological Nitrogen Fixation in Common Bean Genotypes (Phaseolus vulgaris L.)

Fifty common bean genotypes were cultivated in two separately field trials at the research station of Islamic Azad University, Khorasgan Branch during 2008-2009. The experimental design was randomized complete block. Bean seeds were inoculated by Rhizobium legominosarum biovar Phaseoli isolate L-109 in one of the experiments before sowing. The dose of Rhizobium for seed inoculation was 7 miligrams of bacteria for 1 kilogram of seed. The second experiment was control. The second experiment was analyzed in the same way as the first except for biological nitrogen fixation. The results showed definite positive and significant correlation in percentage of nitrogen fixation with some other been characters. Step-wise regression designated that total nitrogen percentage in shoot, number of nodules per plant and biomass yield accounted for 93.8% of variation expect for nitrogen fixation percent. Path analysis indicated that total nitrogen percentage in shoot, number of nodules per plant and biomass yield have direct and positive effect on nitrogen fixation index. Hence, total nitrogen percentage in shoot, number of nodules per plant and biomass yield are promising indirect selection criteria for genetic improvement of nitrogen fixation capability in common bean genotypes

Genetic Improvement of Biological Nitrogen Fixation in Common Bean Genotypes (Phaseolus vulgaris L.)

Fifty common bean genotypes were cultivated in two separately field trials at the research station of Islamic Azad University, Khorasgan Branch during 2008-2009. The experimental design was randomized complete block. Bean seeds were inoculated by Rhizobium legominosarum biovar Phaseoli isolate L-109 in one of the experiments before sowing. The dose of Rhizobium for seed inoculation was 7 miligrams of bacteria for 1 kilogram of seed. The second experiment was control. The second experiment was analyzed in the same way as the first except for biological nitrogen fixation. The results showed definite positive and significant correlation in percentage of nitrogen fixation with some other been characters. Step-wise regression designated that total nitrogen percentage in shoot, number of nodules per plant and biomass yield accounted for 93.8% of variation expect for nitrogen fixation percent. Path analysis indicated that total nitrogen percentage in shoot, number of nodules per plant and biomass yield have direct and positive effect on nitrogen fixation index. Hence, total nitrogen percentage in shoot, number of nodules per plant and biomass yield are promising indirect selection criteria for genetic improvement of nitrogen fixation capability in common bean genotypes

Effect of Ecological Factors on Plant Properties of Thymus daenensis Celak in Different Regions in Southwest and Central Iran

Thymus daenensis Celak. (Lamiaceae) is an aromatic medicinal plant endemic to Iran, intensively utilized because of its wide ranging medicinal and culinary properties. The aerial parts of wild populations of T. daenensis were collected from different populations in Isfahan and Chaharmahal and Bakhtiari provinces, Southwest and Central Iran. The thymol and carvacrol amounts ranged between 13.89 to 35.89 mg g-1 and 6.88 to 23.54 mg g-1 respectively, for populations collected from various elevations. Also, our investigation showed that plant height and date of flowering between populations of T. daenensis had significant difference. The cluster analysis showed that the amount of thymol and carvacrol, and plant height of T. daenensis could be grouped into two distinctive clusters. The results indicate that the amount of thymol and carvacrol of T. daenensis are strongly affected by environmental conditions. Since secondary metabolites are the product of a predominantly biological process further studies are needed to evaluate if the reported characteristics of each population are maintained at the level of individual plants and along the breeding and selection program when grown under different soil and climatic conditions

Effect of Harvest Time on Yield and Quality of Thymus vulgaris L. Essential Oil in Isfahan Province, Iran

Thyme (Thymus vulgaris L.) is a perennial sub shrub belonging to family Lamiaceae. Thyme essential oils have been used for many thousands of years, especially in food preservation, pharmaceuticals, alternative medicine and natural therapies. In order to determine the effect of harvest time on quality and quantity of essential oil in thyme, this experiment was done in a randomized complete block design with three replications at research station of Islamic Azad University, Khorasgan (Isfahan) during 2010-2011. Plants were harvested in five stages: before blooming, beginning of blooming, 50% blooming, full blooming and fruit set. The essential oils obtained from the phenological stages of thyme were analyzed by using GC/MS. The results obtained in our study showed that the phenological stages had very significant effects (P < 0.01) on essential oil yield and percentage as well as thymol percentage and yield. The highest essential oil content of thyme (2.42%) was extracted at the beginning of blooming stage. Analysis and identification of components showed that thymol is the main compound in all samples. The highest thymol content of thyme (74.8%) was extracted at the full blooming stage. According to the results of this research, harvesting the thyme at 50% blooming stage have maximum essential oil quality and quantity in Isfahan province

Determination of the Best Indirect Selection Criteria for Genetic Improvement of Seed Yield in Sunflower (Helianthus annus L.) Genotypes

Correlation and path coefficient analyses were studied on three diverse genotypes of sunflower in order to understand the relationship and contribution on eight characters towards the seed yield. The seed yield exhibits highly significant and positive correlation with plant height, oil yield and total number of seeds per head. Days to full flowering and head diameter showed significant and negative relation with seed yield. Path coefficient analysis revealed that total number of seeds per head had the highest and positive direct effect on seed yield. On the other hand, days to full flowering and head diameter showed the highest and negative direct effect on seed yield. Hence, the study revealed the importance of total number of seeds per head, days to full flowering and head diameter as indirect selection criteria for genetic improvement of seed yield in sunflower breeding programs especially in early generations

Improving postharvest vase-life and quality of cut gerbera flowers using natural and chemical preservatives

Gerbera is one of ten popular cut flowers in the world which occupies the forth place according to the global trends in floriculture. Hence, this study aimed to investigate the effects of chemical, hormonal and essential oil substances in preservative solutions to improve its postharvest qualitative characteristics. Two pulse treatments including distilled water (pulse1) and 4% CaCl2 + 3% sucrose (pulse2) for 24 hour were applied before long-time treatments. Long-time treatments were comprised of (1) Hormonal treatments: 0, 25, 30 mg*l-1 Gibberellic acid, 0, 150, 250 mg*l-1 Benzyl adenine and 0, 100, 200 mg*l-1 5-Sulfosalicylic acid (2) Chemical treatments: 0, 0.4, 0.8 mM Silver thiosulphate, 0, 5, 10 mg*l-1 Nano-silver particles, 0, 4, 6 mM Aminooxy acetic acid and 0, 200 and 400 mg*l-1 8-hydroxyquinoline sulphate (3) Essential oils: Thymus essential oil and Stevia essential oils (0, 0.1 and 0.2 mg*l-1). Data were subjected to analysis of variance based on the factorial experiment model in the layout completely randomized design. Mean comparison was performed using the Duncan’s multiple range test. Parameters of fresh weight, stem bending, capitulum diameter, carotenoid pigments of petal and vase-life longevity were evaluated during 12 days. The highest fresh weight was obtained when cut flowers were held in a solution containing pulse1 + 250 mg*l-1 BA. Among all treatments, 8-HQS treatment showed the best effects on preventing stem bending, increasing capitulum diameter and also on prolonging of vase-life, but nonetheless, the effects of pulse treatments and 8-HQS concentrations were insignificant. To conclude, 200 mg*l-1 8-HQS without pulse treatment has the potential to be used as a commercial preservative solution to improve the keeping quality and vase-life of this important cut flower

Effect of Harvest Time on Yield and Quality of Thymus vulgaris L. Essential Oil in Isfahan Province, Iran

Thyme (Thymus vulgaris L.) is a perennial sub shrub belonging to family Lamiaceae. Thyme essential oils have been used for many thousands of years, especially in food preservation, pharmaceuticals, alternative medicine and natural therapies. In order to determine the effect of harvest time on quality and quantity of essential oil in thyme, this experiment was done in a randomized complete block design with three replications at research station of Islamic Azad University, Khorasgan (Isfahan) during 2010-2011. Plants were harvested in five stages: before blooming, beginning of blooming, 50% blooming, full blooming and fruit set. The essential oils obtained from the phenological stages of thyme were analyzed by using GC/MS. The results obtained in our study showed that the phenological stages had very significant effects (P < 0.01) on essential oil yield and percentage as well as thymol percentage and yield. The highest essential oil content of thyme (2.42%) was extracted at the beginning of blooming stage. Analysis and identification of components showed that thymol is the main compound in all samples. The highest thymol content of thyme (74.8%) was extracted at the full blooming stage. According to the results of this research, harvesting the thyme at 50% blooming stage have maximum essential oil quality and quantity in Isfahan province

Combining Ability of Biological Yield and Harvest Index in Diallel Cross of Wheat Cultivars under Drought and Non-drought Stress Conditions

In order to determine the mode of inheritance, genes action, general and specific combining abilities and effect of various environmental conditions on genetic parameters of harvest index and biological yield in bread wheat, diallel crosses design with eight parents was used. Parents and F1 progenies were sown in a randomized complete block design with three replications under drought stress and non-stress conditions in experimental field of Shahrekord Agricultural Research Center during 2011-2013 growing season. The data were analyzed according to method of Hallauer and Miranda as well as fixed model of Griffing’s method II. Jinks-Hayman model was used to estimate broad and narrow-sense heritabilities and mean degree of dominance. There were significant differences between genotypes for mentioned traits in both conditions. Studying mean square of general combining ability (GCA) and specific combining ability (SCA), the ratio of GCA to SCA mean square and portion of additive and dominance variances showed importance of both additive and non-additive genes effects for harvest index in both conditions, but in biological yield heredity, additive effect was more important. Estimating broad-sense and narrow-sense heritabilities showed low efficiency of harvest index and high efficiency of biological yield for selection programs in both conditions