جستجوی مقالات مرتبط با کلیدواژه "یونجه یکساله" در نشریات گروه "زیست شناسی"

Genus Medicago belonged to family Fabaceae is one of the most important forage legumes. Annual species of this genus are indigenous to Mediterranean region and used for prevention of soil erosion, green manure and forage. In this research, genetic variability and classification of 14 annual medicago truncatula genotypes using ISSR markers was done. 9 out of 15 ISSR primers which possessed suitable polymorphism and amplification were used for fingerprinting of studied genotypes. Totally, 71 bands were amplified via ISSR primers which 11 bands were monomorphic and 60 bands were polymorphic across genotypes. Based on Jaccard similarity coefficient, minimum similarity (0.25) was seen between TN8.3 (Tunisia) and TN6.18 (Tunisia) and maximum similarity (0.82) was seen between TN8.3 (Tunisia) and SA28064 (Cyprus). Population structure analysis using STRUCTURE software subdivided them into 9 subpopulation. In this study, maximum admixture was occurred in TN1.21 (Tunisia), A10 (Australia), F83005-5 (France), SA22322 (Syria), A20 (Australia), and DZA315-16 (Algeria) genotypes. Results revealed that annual self-pollinated M. truncatula had noticeable genetic variation which Is accurately detectable using ISSR molecular markers.

The objective of the present study was to investigate the effect of electromagnetic field (88 and 128 µT) and exposure times (12 and 24 hours for weed seeds and 10 and 30 minutes for crop seeds) on annual medics (Medicago radiata, Medicago scutellata and Medicago polymorpha), barley (Hordeum vulgare), dodder (Cuscuta monogyna) and barnyard grass (Echinochloa crusgalli) seed germination. There were differences among different treatments (P≤0.01) for root, shoot and seedling dry weight in barnyard grass. Fresh weight and seedling vigor index were different between treatments (P≤0.05). There was no significant difference among treatments for germination percent, index and rate coefficient in barnyard grass. Electromagnetic intensity affected root dry weight of barnyard grass and increased this parameter in comparison with control. There were differences among treatments for germination percentage, shoot length and dry seedling and shoot weight and seedling vigor index in dodder seeds (P≤0.01). Seedling vigor index and dry weight decreased in dodder seeds under different electromagnetic intensity. Electromagnetic intensity enrichment increased germination rate and percentage and shoot length of annual medic species. The greatest germination rate and percent of crop seeds were obtained at electromagnetic intensity of 128 micro tesla, when they exposed for 10 minutes.

The objective of the present study was to investigate effective methods in breaking the seed dormancy for two annual medics’ species. Three experiments were conducted to evaluate seed germination of two annual medics including Medicago polymorpha and Medicago rigidula under different prechilling, gibberellic acid and potassium nitrate concentrations and sulfuric acid concentrations in 5 and 10 minutes of applying time. The result showed that all methods broke seed dormancy and exhibited seed germination of annual medics, but some cases were different in species. The most effective and practical method for seed dormancy breaking in M. polymorpha and rigidula was %96 sulfuric acid application for 10 minutes. The main advantages of this method are speed, ease of use, and unaltered physical condition of the seeds following treatment and cheap.