Yazar "Tiryaki, Iskender" seçeneğine göre listele

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    A novel method to overcome coat-imposed seed dormancy in Lupinus albus L. and Trifolium pratense L.
    (Hindawi Publishing Corporation, 2014) Tiryaki, Iskender; Topu, Mustafa
    We have developed a novel method to overcome coat-imposed seed dormancy in legume plants. Seeds of Lupinus albus L. and Trifolium pratense L. were stored in a freezer at -80°C for a period of time and then immediately treated with or without hot water at 90°C for 5 seconds. Germination tests were carried out in darkness at 20 ± 1.0 °C with four replications in a completely randomized design. Final germination percentage (FGP), germination rate, and synchrony of seeds were evaluated. The results showed that new approach of freeze-thaw scarification provided high percentage of germinations in white lupin (84.16%) and red clover (74.50%) seeds while control seeds had FGPs of 3.3% and 26.0%, respectively. The immediate thawing of frozen seeds in hot water for 5 seconds was found not only an effective and reliable but also the quickest seed treatment method to prevail against coat-imposed seed dormancy in legume species and may become operationally applicable to other plant species. © 2014 Iskender Tiryaki and Mustafa Topu.
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    Adaptation Mechanisms of Some Field Plants Against to Salt Stress
    (Kahramanmaras Sutcu Imam Univ Rektorlugu, 2018) Tiryaki, Iskender
    Soil salinity is one of the most important abiotic stress factors which directly limits plant yield in agricultural production areas around the World. Salt stress also determines plant diversity in agricultural production areas. Development and revealing of plant response against to salt stress depends on physiological changes of plants controlled by complex molecular mechanisms which subsequently lead to development of tolerance. Sometimes, such changes and differences appear to be unique to the type of plant, but some other times, such responses are more common and similar in all plants. In addition, although such complex mechanisms appear to be developed directly related to salt stress per se, they may also be the results of other abiotic stress, like drought, or even biotic stress related responses. Therefore, better understanding of salt tolerance at both plant and mechanism levels will make significant contribution to develop better salt tolerant new plant varieties. The aim of this review was to make contribution on understanding of plant response against to salt stress based on current literature.
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    An Alternative Cereal: Forgotten a New Plant from The Past
    (Kahramanmaras Sutcu Imam Univ, 2018) Sari, Ugur; Tiryaki, Iskender
    Changing lifestyles and eating habits from the past to the present, and increasing availability of ready-to-eat foods in daily diet along with increasing health problems promted consumers to look for alternative herbal nutrients over time. Such ongoing quests have led to the development of new plant varieties and the reconsidering of existing nutrients in terms of healthy nutrition and diet quality criteria. At the same time, such searches have led to the resurgence of plant species and varieties that have been produced using traditional or primitive agricultural methods in very marginal areas of the world, where cultivation has been abandoned for a variety of reasons, or which are still underdeveloped. Since such plants, which can also be called as fashion-plants, are announced to consumers by the press, those plants are demanded by the consumers and such demand creates new markets. The rediscovery of such plant species, which seem to have been completely forgotten in the past, is expected to become even more popular in the near future if they are addressed by different aspects of today's plants, as compared to the basic plant species and varieties that make up a large part of people's daily diet around the worldwide. As a natural plant of Ethiopia, teff [Eragrostis tef (Zucc.) Trotter] is also considered as one of such fashion-plants and takes place very important role in daily diet of people of the region. The plant has recently been shown as an alternative source of carbohydrates in terms of balanced nutrition in different parts of the world. New scientific studies are causing the plant to become more recognized and to increase its importance. This study has been prepared to introduce many aspects of teff plant which may have an important agricultural potential in near future for our country.
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    Determination of salt tolerance levels and genetic relationships of Vicia sativa cultivars using gene targeted functional markers
    (Univ Zagreb, Fac Science, Div Biology, 2022) Tiryaki, Iskender; Isidogru, Nuray
    - The objectives of the present study were to determine salt tolerance levels of 12 different common vetch (Vicia sativa L.) cultivars at germination stage in the presence of 250 mM NaCl and to reveal genetic relationships based on gene targeted functional markers (GTFMs) associated with salt tolerance. The results revealed the presence of a significant genetic variation among the cultivars although salt stress significantly reduced all germination parameters tested. The cultivar Ozveren was the most salt tolerant with 20.1% reduction in final germination percentage compared to control seeds while cultivars Alinoglu, Ayaz and Bakir did not germinate. The maximum delays in germination rate (G50 = 3.78 days) and synchrony (G10-90 = 3.45 days) were obtained from the cultivars Urkmez and Ozveren, respectively. The GTFMs provided a total of 53.1% polymorphism. The primers of MtSOS2 gene gave the highest numbers of alleles per primer pair while the highest polymorphism rate (77.8%) was obtained from the MtP5CS gene. The first three components of principal component analysis explained 57.63% of total variation. This study concluded that the cultivars determined to be salt tolerant and sensitive at germination stage distributed into three main clades determined by UPGMA analysis while the GTFMs associated with salt tolerance successfully determined the genetic relationships of common vetch cultivars.
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    Drought Stress and Tolerance Mechanisms in Alfalfa (Medicago sativa L.)
    (Kahramanmaras Sutcu Imam Univ, 2016) Tiryaki, Iskender
    Drought is one of the major abiotic stresses threatening agricultural productivity all around the world. Alfalfa (Medicago sativa L.) is the most important forage crop in temperate regions whose importance may further increase because of its positive contribution to sustainable agriculture and its productivity on animal feeding. Although 3-4 years old alfalfa is relatively drought tolerant, it is very vulnerable to drought stress at germination and early seedling growth stages as well as at regrowth stage right after grazing. On the other hand, development of drought tolerant alfalfa varieties by selection or classical crossing is very difficult to due to low heritability of drought tolerance traits and longtime requirement. Introduction of foreign drought tolerant varieties comes along with adaptation and royalty payment problems. Although it is possible to develop relatively drought tolerant transgenic varieties by applying biotechnological approaches, the acceptance of such crops are still controversial and planting of those crops is not allowed in our country. Therefore, success for development of drought tolerant new plant genotypes will depend on understanding of stress related morphological, physiological and molecular mechanisms, and collective use of such new breeding approaches. The aim of this study is to help the understanding of drought stress and tolerant mechanisms of plants, specifically alfalfa, under the light of current literature.
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    Enhanced germination performance of dormant seeds of Eragrostis tef in the presence of light
    (Centro Int Agricultura Tropical-Ciat, 2019) Tiryaki, Iskender; Kaplan, Sakir Anil
    Lack of germination or low germination due to seed dormancy prevents successful crop establishment in several important plants. To determine the presence of innate seed dormancy and effects of stress-related plant hormones on germination performance of Teff (Eragrostis tef) seeds, we primed seeds in 1% KNO3 for 24 hours in dark conditions at 21 +/- 0.5 degrees C along with varying concentrations of chemicals known to influence seed germination, including: acetyl salicylic acid (ASA); methyl jasmonate (JA-Me); giberellic acid (GA(3)); and indole acetic acid (IAA). Primed seeds were incubated either in constant light (210 mu M/m(2)/s) or in darkness at 21 +/- 0.5 degrees C. The results indicated that priming significantly improved final germination percentage (FGP) in both light (92.5%) and dark (89.4%) conditions compared with untreated seeds. The inclusion of plant hormones in the priming media generally had limited effects, except for 10 mu M ASA (94.5%) and 100 mu M GA(3) (92.5%). ASA generally provided faster seed germination than seeds primed in 1% KNO3 only, while the other plant hormones had no effect on the time required for 50% of FGP in the dark. Priming had no significant effect on time span of germination in either light or dark incubation conditions. The results demonstrate that E. tef has light-inducible seed germination and about half of freshly harvested seeds can be dormant, which can be eliminated to some extent by priming seeds in 1% KNO3.
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    GABA-mediated modulation of drought stress tolerance and seed morphology during flax (Linum usitatissimum L.) germination via image analysis
    (Nature Portfolio, 2025) Cetin, Selcuk; Tiryaki, Iskender
    Seed coat color, a trait exhibiting significant phenotypic variation, has been reported in previous studies to influence key germination parameters, including germination percentage, germination rate, and mean germination time. Looking into these relationships can help us identify plant varieties that better withstand both living threats and environmental challenges, which would make breeding programs more effective and focused. The objectives of this study were to evaluate the drought tolerance of 20 flax varieties at the germination stage, investigate the effects of gamma-aminobutyric acid (GABA) on seed germination performance under drought stress conditions, and explore potential associations between seed coat color and germination parameters under both stressed and non-stressed conditions using digital image processing. The final germination percentage, germination speed, and span of germination were assessed for seeds germinated under various germination conditions, including 23% PEG (- 0.169 MPa), 10 mM GABA, 23% PEG + 10 mM GABA, and a control treatment at 25 +/- 0.5 degrees C. The results demonstrated substantial genetic variation across all germination parameters measured in the seeds of 20 distinct flax varieties. Genotype-specific responses to drought stress were observed, with 10 mM GABA alleviating the effects of drought. Among the varieties tested, Hermes exhibited the highest drought tolerance, while Lisette and Bonny-Doon were identified as drought-sensitive. Digital image processing analysis revealed significant differences (p < 0.05) in drought tolerance levels among flax varieties based on variations in RGB values of their seed coats. Although no statistically significant correlations were found in direct pairwise correlations between the color parameters converted from RGB (Red, Green, and Blue) to L*a*b* and germination parameters, multivariate PCA-biplot analysis indicated that L* and b* values had a positive influence on germination performance. In contrast, seeds with higher a* values exhibited reduced germination performance. Furthermore, the biplot analysis suggested that varieties with lighter seed coats tended to show better germination compared to those with darker seed coats. These findings highlight the potential of incorporating seed coat color parameters into flax breeding programs, suggesting their role in enhancing seed germination and overall seed quality under various stress conditions.
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    Genetic relationship and nuclear dna content variation in Tef [Eragrostis tef (Zucc.) Trotter] accessions
    (Springer, 2020) Kaya, Caglar; Tiryaki, Iskender; Sari, Ugur; Tuna, Metin
    This study was initiated to reveal genetic relationship of 25 tef (Eragrostis tef (Zucc.) accessions by using 10 SSR markers and to determine DNA content variation by using flow cytometer analysis. Ten markers produced a total of 18 alleles and 11 of those were polymorphic. The mean polymorphism rate was 66.6%. The highest polymorphism information content value was obtained from marker CNLTs370 with 0.69 while markers CNTLs11 and CNTLs133 produced monomorphic bands only. UPGMA analysis divided 25 tef genotypes into three main clades. The accessions PI193511 and PI195934 were distinctly separated from the others. No ploidy differences were determined among the 25 tef accessions. 2C mean nuclear DNA content ranged from 1.406 pg to 1.510 with mean of 1.460 pg. The results of this study indicated that SSR markers successfully determined genetic relationship of 25 tef accession although they had a low rate of polymorphism. This study also revealed that available tef related SSR markers should be optimized before use and their efficiency may vary based on tef genotypes or accessions used.
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    Genetic variation among einkorn genotypes based on gene targeted functional markers and its possible relationship with drought tolerance at seed germination stage
    (Springer, 2022) Yilmaz, Enes Gokhan; Tiryaki, Iskender; Sari, Ugur
    Background Einkorn wheat is one of the first primary genetic resources for discovery of new alleles related to biotic and abiotic stress tolerances for further genetic improvements while it became more popular especially for its native grain status as healthy food resources. Therefore, this study aims to determine germination parameters of 32 local einkorn (Triticum monococcum) genotypes collected from Kastamonu and its vicinity, Turkey under drought stress conditions, and to reveal the genetic relationship of those genotypes based on drought related gene targeted functional markers (GTFMs). Methods and results Germination test was conducted at 20 +/- 0.5 degrees C in darkness with randomized complete block design with 4 replications. Seeds placed on double filter papers in a covered glass petri dishes (80 x 15 mm) were treated with polyethylene glycol (PEG(6000)) with a -0.23 MPa. The final germination percentages (FGPs), speed and span of germination parameters were determined. Drought stress severely worsened all germination parameters measured. The genotypes SG24 and SG12 were the most drought tolerant and sensitive genotypes based on 21.1% and 64.8% of reduction rates in FGPs, respectively. Twelve GTFMs produced a total of 32 bands and 26 of them were polymorphic. The mean polymorphism ratio of the markers and average band per marker were determined as 86.31% and 2.66, respectively. The highest polymorphism information content (PIC) was obtained from AIB1 gene marker (0.875). Conclusions This study revealed that there was a significant genetic variation for drought tolerance levels of local einkorn wheat genotypes at germination stage and drought related GTFMs can be used not only to reveal genetic variation but also to distinguish the drought tolerant genotypes.
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    Improved drought tolerance of EMS mutagenized Alfalfa (Medicago sativa L.) mutants by in vitro screening at germination stage
    (Nature Portfolio, 2022) Tiryaki, Iskender; Sari, Ugur; Cetin, Selcuk; Acar, Okan
    The objectives of this study were to determine drought tolerant novel mutant of alfalfa (Medicago sativa L.) genotypes by screening EMS mutagenized 340675 M-3 seeds at germination stages in the presence of osmotic stress of 35% PEG(6000). Root growth assay provided several drought tolerant candidate mutants. Of those, 4 mutants were further evaluated at water deficit conditions applied for 24 days after the first cutting at flowering bud stage. The results revealed that mutants determined as drought tolerant at germination stage were also tolerant to water deficit conditions. Protein content and superoxide dismutase values were found to be higher in all mutants than controls. Ascorbate peroxides, glutton reductase and lipid peroxidase values varied based on the mutant genotype and duration of drought stress. Drought stress significantly changed transcriptional levels of MtP5CS, MtDehyd, MseIF-2, MtRD2 and MsNAC genes. These results indicated that in vitro screening of alfalfa mutant seeds for osmatic tolerance at germination and early seedling growth stages was successfully able to determine the drought tolerant alfalfa mutants which were also tolerant to water deficit conditions after the first cutting at flowering bud stage.
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    Revealing Seed Coat Colour Variation and Their Possible Association with Seed Yield Parameters in Common Vetch (Vicia sativa L.)
    (Wiley, 2016) Tiryaki, Gulgun Yildiz; Cil, Abdullah; Tiryaki, Iskender
    The seed coat colour variation of 70 common vetch genotypes were determined by using uniform colour scale (L*a*b*) and their possible correlation with seed yield parameters including the number of pods per plant, the number of seeds per pod, pod dimension, and seed yield (kg/da) was determined. The results revealed presence of highly significant (p < 0.01) variations for both the seed yield and the seed coat colour parameters measured. The number of pods per plant, the number of seeds per pod, and seed yield ranged from 5.8 to 16.03, from 5.2 to 7.66, and from 143.37 to 531.1, respectively. The lightness value varied from 19.00 to 40.28 while chromaticity a* and b* values ranged from -0.16 to 8.99 and from 0.79 to 22.11, respectively. The highest correlation coefficients were determined between b* and L* (r = 0.73), and a* and L* (r = 0.55). The seed coat colour traits and seed yield parameters generally showed weak negative correlations. Seed yellowness (b*) and seed yield had correlation coefficient of -0.25, while correlation between L* and seed yield was determined as -0.23. The results indicated that lightness and yellowness of seed coat may be used as an important parameter to prescreen high yield genotypes of common vetch.