جستجوی مقالات مرتبط با کلیدواژه "باغ بذر" در نشریات گروه "علوم پایه"

According to the development of Iran's natural resources in horizon 1404, afforestation and reforestation of about 2,200,000 hectares in the fourth five-year plans are predicted, of which 100,000 hectares are related to Arasbaran forest. Identification of seed sources and forming seed orchards is one of the safest ways to supply standard seeds and seedlings to achieve the goals of the natural resources development document so that 1) standard seeds are provided to the executive organization and 2) genetic drift of the forest does not occur. Juniper (Juniperus foetidissima Willd) is one of the endangered species that has a special role in the composition and diversity of Arasbaran forests. This species is highly resistant to adverse environmental conditions, and now most of its trees are in the harshest living conditions. In this study, based on the number of seed production areas and their distribution, the number of trees and the distance between them, the area of seed production zones, and the characteristics of elite trees, eight areas in the Arasbaran forest were identified as primary seed production areas. The geographical coordinates and map of these areas show a suitable and balanced geographical distribution for the juniper seed production area in the Arasbaran forests. Conducting molecular studies, progeny testing, and genetics studies on these trees can be very useful for studying the genetic diversity and structure, preparing the molecular identity, and determining the genetic affinities between and within different juniper populations to establish a seed orchard.

supplying the certified and suitable seeds and seedlings of forest trees and shrubs species that have suitable compatibility and genetic diversity for different vegetation areas of the country has been accepted as a prerequisite for executive programs in forest rehabilitation and development. Since the strategic plan for forest development of Iran, envisages about 2,000,000 hectares of seedling planting or seeding in a 10-year duration, it is necessary to pay more attention to the development of seed orchards as a tested strategy. Based on the existing research-executive experiences, models should be presented that, by creating a balance between genetic diversity and genetic gain, have the necessary efficiency in mass production and quality seeds and seedlings in the short, medium, and long term. With this approach, seed supply sources in Iran will include both seed production areas and seed orchards. Therefore, in order to form a seed orchard in different vegetation areas, first, the seed production areas are identified and evaluated. By genetic and phenotypic evaluation of the seed production areas (by molecular methods and progeny tests), suitable rootstocks for temporary seed supply before the formation or sowing of seed orchards or in some cases due to the impossibility of forming the seed orchard, to be permanently identified, selected and managed. In the next step, by combining the data related to molecular studies and the results of progeny tests, an appropriate number of maternal rootstocks, and the seed orchard formed with the seedlings of these maternal plants.

The research was performed to evaluate the genetic potentials and variation of Haloxylon persicum genotypes, and establishment of a seed orchard, using the selected genotypes of the species in Yazd province. The study was conducted in the desert research station of Shahid Ayatollah Sadoughi, located in Askezar city.The seeds of fifteen genotypes were collected from natural habitats and planted in plastic pots during early spring.The seedlings were transplanted into the seed orchard after two months based on the orchard plan.Several traits including plant height, crown diameter, vigor, and susceptibility to powdery mildew were recorded on the plants.The data were analyzed using the correlation coefficient analysis.The genotypes with a vigorous crown growth and seed production were regarded as the best genotypes for seed production.Therefore, the best progenies were observed for three of the genotypes studied, whereas, the progenies of four other genotypes didn’t show any superiority.

Nowadays, optimized utilization of forests potentials and seed orchard establishment is not an option rather it is an obligation. In countries such as Iran, which are considered as low forest countries, forest seed orchard establishment is a non-replaceable exigency. This is in such conditions in which unsystematically exploration of forest tree species has caused genetic deterioration and reduction of genetic variation of a great number of valuable forest tree species. Following fulfillment of a national research project on investigation of genetic potential of Haloxylon species, six populations of H. aphyllum collected from Khorasan Razavi, Qom, Yazd, Semnan, Kerman and Sistan and Baluchestan provinces were primarily investigated by which a number of suitable trees with appropriate performance were selected. The selected trees were further investigated by progeny testing in the six provinces. A number of superior genotypes were selected on which H. aphyllum seed orchard was established in Qom, Khorasan Razavi, and Yazd provinces. Using collected seeds on the selected plus trees, seedlings were produced, and a further selection was performed on the seedlings and planted in the seed orchards in such a way that the least relationship could be found between adjacent stands. Optimization of genetic variation in the mentioned seed orchards should be dynamically continued, along with utilization of their outcomes.