tailieunhanh - Báo cáo lâm nghiệp: "Hybridization techniques and frost tolerance studies in intraspecific hybrids of Eucalyptus globulus Labil"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Hybridization techniques and frost tolerance studies in intraspecific hybrids of Eucalyptus globulus Labill. | 54s Ann. Sci. For. 1989 46 suppl. 54s-55s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Hybridization techniques and frost tolerance studies in intraspecific hybrids of Eucalyptus globulus Labill . Almeida1 and . Leal2 11nstitute Superior de Agronomia Forestry Dept. Lisbon and 2CELBI Celulose Beira Industrial Quinta do Furadouro Obidos Portugal Introduction Hybridization techniques have been developed since 1985 in a clonal seed orchard of E. globulus located in the central coastal area of Portugal. The objective was to enlarge the genetic base of the E. globulus population. In intraspecific hybrids seed characteristics and growth were evaluated in the field and frost tolerance studies were made in a temperature-controlled chamber. Materials and Methods Controlled pollination Controlled pollination techniques were developed in grafted material in 3 clones 27 trees . A total of 2327 flowers were pollinated. At anthesis the operculum was removed manually and emasculation was done with a blade. The flowers were then isolated with unwoven teryle-ne bags Optimum stigma receptivity shown by an exudate was determined using controlled pollinations made over 2 d intervals from d 4 to d 14 in groups of 60 flowers. In each group the proportion of flowers with stigmatic exudations was recorded. Controlled pollinations were made with a brush. Seed production rate of germination and survival of seedlings were evaluated in cross- self-and open-pollinated flowers using 100 seeds from 20 capsules per seed type. Some of these seeds were planted in the field and evaluated for growth. Frost tolerance Twelve uniform seedlings from each of 3 full-sib families were subjected to 8 h of light at close to 25 c outdoor 16 h of dark at 4 c in a cold room A second comparable group of seedlings remained outdoors under favorable growth conditions and after 3 wk the 2 groups were randomized and subjected to either 1 outdoor conditions control 2 C or 3 c. The .