Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research
Year:2003 | Volume:11 | Issue:3|Papers Count:9

Studies have shown that more than 250000 plant species growing around the world. Understanding of how many plant species could give well service to all of human, animals and environmental needs is not too easy. Plant breeder’s successfulness is related to variation within and between collected seeds of plant species. Experiences have shown that plant seed collections have to be managed to face with high amount of variation but less number of accessions (Core Collection). To reduce the budget requirement for seed collections, identifications, evaluations, storage, seed exchanging and data management, core collection has to be considered at first. If germplasm maintainers in all countries, looking after the seed collection only, and priorities not considered, problems in cold seed storage would be appeared. Overcoming the matter, for forage's seed collection, palatable characteristics, and for plant medicine's seed collection, extractable materials or essences has to be looked as priorities. Regarding these priorities, variation within plant species, decision making about plant seed collection's methods and selection of geographical seed collection sites which have high variation of plant species, are most necessary to look about. If seed collection continued without considering different limitations, this action will bring to gene banks some additional budget requirement and works, without significantly helping more plant production. In present paper, it has been tried to report and analyze a successful mission, which focused to collect range and medicinal plant seeds, in some parts of Zagros Mountain areas. Comparing with other methods of seed collection, presented method was shown to be much more effective, and could be followed as a good model in future.

In order to mass propagation of Sequia sempeivirance (Lamb) End I through in vitro culture, mature embryo of seed were isolated and transferred to the media. MS supplemented with 100-mg/l-casein hydrolease, 0.1 mg/l adenine-sulfate and 1 mg/l yeast extract produced highest germination of embryos (68/7%). In vitro embryo-derived shoots were used as a source for proliferation through stem cutting and adventitious shoots regeneration on a modified MS (Murashige and Skoog, 1962) agar medium supplemented with 10 mg/l 2iP, 0.5 mg/l BA and 0.1 mg/l NAA. Further multiple shoots were obtained from nodal segments taken from in vitro proliferated shoots when culture in MS medium containing 0.5 mg/l BA, 0.1 mg/l NAA and 10 mg/1 2ip. Rooting of the shoots was achieved on MS medium supplemented with 0.5 mg/l 2ip (35%). Plantlets survived in poting soil and exhibit normal growth under greenhouse conditions.

In order to investigate in vitro culture of Taxus baccata, apical buds were cut in autumn from selected mature trees at Astara, Asalem forest in Gillan and Aliabadkatol in Golestan province, Iran. Application of 0.1% mercuric chloride solution for 10 minutes was the most effective way for the surface sterilization of the buds. Then the buds were cultured on MS (N/2), B5 and MCM medium plus BA (0.5- 1 mg/L) + IBA 0.1 mg/L. The best treatment for shoot proliferation and elongation was MS (N/2) medium containing 0.5 mg/L BA+ 0.1 mg/L IBA.The shoots were treated as cuttings by dipping the basal ends in 50 mg/L IBA solution for 24 hours, then they were placed in an auxin- free medium plus 1% activated charcoal, for stimulating rooted shoot propagation. Rooted plantlets after acclimation were transferred to mixed soil with equal parts of (vermiculate, sand and peat) under greenhouse conditions.

The main goal of this project is to preserve genetic resources of forests by vegetative propagation of adult trees. Fagus orientalis Lipsky, which its micropropagation, investigated in this project, is one of the most important trees in the forests of Iran. Buds were taken from 3 different genotypes grown in the north forests of Iran. Surface sterilization of the explants was very difficult. Elimination of first three layers of the bud scales was necessary. Intact bud scales caused severe contamination even with very strong sterilizing treatments. Using %0.1 (w/v) solutions of mercuric chloride for 3 minutes was the most effective way for surface sterilization of the explants. The rate of shoot and bud development was very low, and this was the same on WPM and DKW. Culturing established buds horizontally, cold treatment or high auxin concentration pretreatment activated axillary buds. Using 0.2mg/l 2ip (6-dimethylamino purin) together with 0.5 mg/l BA (benzylamino purin) improved shoot proliferation. There were no significant differences between the three genotypes. None of the micropropagated shoots were rooted.

Manns with sweet taste are products which leach out from tree's leaf, bark and limb both naturally or through insect’s activity. This product may also secret from the trunk of some trees, when they are wounded.In some of the species in Echinops genus Echinops mann is obtained through the activity of an insect (Larinus vulpes Olivier). Investigations carried out during 1997-1999showed that in spite of Larinus activities on all species of Echinops, mann is only produced on 4 species of Echinops endotrichus, E. dichrous, E. tenuisectus and E. persepolitanus. Morphological investigations indicated that mann productive species have spherical aggregated flowers, and all have almost similar plant height. Moreover growing zone studies showed that mann productive species grow in the same altitude range. Based on cytological studies, all Echinops species are diploid. The mentioned four productive species are also diploid with 2n=28.

To determine the distribution of Cicer species in Fars province, during the year of 2001, different parts of this province were visited and 18 habitats of various species were recognized. For identification the species, plant samples were collected from all habitats and 7 species C. arietinum, C. kermanense, C. tragacanthoides, C. spiroceras, C. subaphyllum. C. stapfianum and C. oxydon were identified. Chromosome studies on seedling root meristems such as: detection of chromosome number and karyotypic ideogram showed that all of the species were diploid and the chromosome numbers were 2x=2n=16. Genome analysis including the length of each chromosome, long and short arm length, long -short arm length ratio were performed. Using the table of Levan and Stebbins method, the type and karyotypical characters of the chromosome were identified.

In order to examine and evaluate the variation and process of deterioration of seeds of Secale montanum accessions, which have been collected in natural resources genebank, this research was carried out. Eleven accessions were examined in a completely randomized design with three replications under two different conditions, germinator and glasshouse.The recorded traits of the germinator test included, germination percentage (G.P.), speed of germination and vigor. The recorded traits of the test in glasshous, included G.P., speed of germination, plant height, number of tillers and root length in 40 days after planting. Significant difference was found between accessions for many of the studied traits. Variation between accessions was significant in one or both of the environments.The results of Correlation coefficient analysis showed negative correlation between reduction of G.P., speed of germination and seed vigor in germinator condition and G.P., speed of germination and plant height in glasshouse condition. Therefore, seed deterioration not only reduces G.P, but also decreases the speed of germination and seed vigor.In all of the Secale montanum accessions, because stored samples of each year were different from other years, therefore reduction of G.P., was highly affected by origin of accessions. It was not possible to differentiate between the effect of maintaining condition and origin of seed. It was suggested that, for better genebank management, accessions, have to be considered as regeneration unites of collected seeds.