نشریه تحقیقات ژنتیک و اصلاح گیاهان مرتعی و جنگلی ایران
سال پنجم شماره 1 (پیاپی 5، پاییز و زمستان 1379)

In order to develop somatic embryogenesis for genetic manipulation process of Populus deltoides Bartrex Marsh eastern, isolated leaf disk explants were cultured on MS medium supplemented with 2,4-D (2,4-dichlorophenoxyacetic acid), BA(benzyladenine) and glutamine. High number of somatic embryos formed on both the midveins and secondary veins. MS medium containing 2 mg/l 2,4-D and 0.1 mg/l BA with 20 J.LM glutamine showed highest number of globular-shaped embryo (11.6). Most of the embryogenic calli were formed on the cut edges of the leaf disks in MS medium containing 5 mg/12,4-D and 0.1 mg/1 BA for all glutamine concentrations. MS plant regeneration media supplemented with 2 mg/l BA and 0.1 mg/1 NAA (Naphtalene Accetic Acid) produced high percentage (72.5%) of plantlets on callused leaf disks explants. Rooted plantlets in WPM basal medium were successfully acclimatized on soil medium (1:1:1 peat, perlit and vermiculite) and transferred to the field.

Calli were induced from both mature and immature embryos of a wild barley species (Hordeum murinum) and of cultivated barley (H vulgare). Mature embryos produced soft watery and translucent cultures with the characteristics of non-embryogenic (NE) callus. Such cultures grew slowly and presented merely some root formation. Cultures derived from immature embryos showed the characteristics of NE calli primarily, most of which grew slowly. From these calli rapidly growing calli were produced in cultivated barley, characterized as being dry firm and granular or with small clumps and yellowish to white in color. Shoot-like structures emerged on these cultures and the shoot and root development occurred on regeneration medium. The well-developed planletes grew normally after transferring to soil and reached to maturity and seed production phase.

The genus Onobrychis in the family of Papilionaceae has 56 species in Iran. These species have been adapted to various climates of the country. Therefore, they are valuable germplasm for applied plant breeding. Karyotype study of different species of a genus is a primary work but basic step in cytogenetical studies because kariotype study provides valuable information for the researchers. In this work, eight species were studied. Plant and seed samples were collected from different habitats of Fars province. Different treatments were applied to root tip meristems to get cells in metaphase stage. Results showed that Onobrychisgaubae, O. melanotricha, O. aucheri ssp Teheranica and O. sojakii with 2n = 16 chromosomes and O. ptolemaica with 2n =14 chromosomes are diploids. O. aucheri ssp. psammophila and O. crista-galli with 2n=32 chromosomes and O. vicifolia with 2n=28 chromosomes are tetraploids. These results also showed that the genus Onobrychis has two genome numbers (x= 7 or 8) which corresponds to the previous researches.

Lucern (Medicagosativa L.) is one of the forage plants which due to its various characteristics is called the "Queen of the Plants". It is said that annually about 128 million tons of lucern seed is required all around the world. On the other hand, the world's average seed yield per hectar is less than 200 kilo gram. Regarding several main points, this can be increased. So that an average yield of 2422 kg lucern seed yield is recorded. This is tried to present the ways of applying the maximum available potentials of the environment for lucern seed production in this article. For this reason, several factors which are involved in decreasing and increasing lucern seed yield are discussed.

In order to investigate genetic variation between existing cultivars and populations of alfalfa (Medicago sativa), twelve accessions were randomly selected from Natural Resources Gene Bank, and several studies were carried out on them. Seed storage protein electrophoresis was performed on the accessions using SDS-PAGE technique. Based on the results of this study, the protein bands were fairly similar. However, there was a remarkable difference between the accessions based on the two distinct bands. Cluster analysis was also performed on the cultivars and accessions. The accessions with a distinct different band in electrophoresis gel located in a common group in cluster analysis. Over ally, classification based on cluster analysis showed a similar trend to the electrophoresis gel.

Perennial ryegrass is one of the most important forage species in temperate regions throughout the world. This species is spread in north and west of Iran i.e. Alborz and Zagros Mountain rangelands. Because of the importance of Lolium perenne in grassland productivity any improvement in dry matter yield, would be very beneficial in terms of animal productivity. In order to study the genetic variation among local and foreign accessions/ varieties of perennial ryegrass in Natural Resource Gene Bank, and the study of ploidy x maturity interaction effects on dry matter yield, an experiment was conducted at Alborz Research Center, Karaj, Iran. Seedlings of 29 accessions/ varieties were transplanted in the field. Each row plot contains five spaced plants were established using a complete block design with three replications. Forage dry matter yield, basal cover, ear emergence date, pollination date, stem number, stem height and persistency were assessed in four harvesting dates. Significant differences were observed for all of the characters for each cut. For ear emergence date, there was 42 days interval between the earliest and the latest maturity accessions. Moy, Yatsyn and Syrachal were the earliest and, Carrick and Sarsfield were the latest varieties. For annual dry matter yield, Spega and Magician with more than 13 tons/hectare and Tivoly with 6.31 tons/hectare had the highest and the lowest forage dry matter yield respectively. There were also significant differences between cuts. Dry matter yield decreased over the seasons. The first cut had about 50 percent of total annual yield. In overall, tetraploids produced more dry matter yields than diploids. But, diploids had a high ratio of reproductive tillers that indicated their high potential of seed production. Estimates of broad sense heritability, although low, suggested that response to selection should be possible and recurrent selection based on progeny testing should be effective.