Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 6

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  gene conservation
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Manipulations of poultry embryonic cells

100%
Varkonyi E., Hidas A., Szalay I.
Zeszyty Naukowe. Przegląd Hodowlany
|
1997
|
tom 31
2
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Distribution of Lihtuanian Scots pine trees according to breeding categories and their seed production in seed stands

100%
Gabrilavicius R.
Dendrobiology
|
2002
|
tom 47 Supplement
In addition to other traits, value of stands for breeding can be evaluated according to the number of plus trees and productive trees. According to this property, stands with the highest value for breeding are located in eastern Lithuania. Trees start to differentiate into breeding categories at the juvenile stage: in Scots pine stands on Pinetum myrtillosum sites, at the age of 6to 8 years and in Scots pine stands on Pinetum vacciniosum sites, at age of 10 to 12 years. According to radial increment, the trees start to differentiate into selection categories of productive, medium and minus trees, which often remain in these categories until mature age. The following four types of radial increment of trees were distinguished: (1) fast growth at the juvenile stage, followed by a gradual decrease, (2) fast growth at the juvenile stage, followed by a stable growth from age 20 to 30 years, (3) slow growth at the juvenile stage, followed gradual increase, (4) unstable growth all the time. In Lithuania, abundant seed yield used to occur in three to four year intervals. Populations with abundant flowering may produce approximately 10 kg of seeds (filled and empty) per ha, while the populations with weak flowering - 1 to 2 kg per ha. In mature Scots pine stands of stocking level ca 0.7, 6to 8% of the seeds are produced by plus trees, 24% by productive trees, 55 to 60% by trees of medium productivity and 10% by minus trees. Being suppressed, minus trees produce 2% of the seeds only.
3

Present state and gene conservation of noble hardwoods in Slovakia

80%
Gomory D., Longauer R., Paule L.
Zeszyty Naukowe Akademii Rolniczej w Krakowie. Sesja Naukowa
|
2002
|
tom 86
345-354
4
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Gene conservation and breeding programmes for Picea abies in Lithuania: present-day achievements

80%
Danusevicius J., Gabrilavicius R., Danusevicius D.
Dendrobiology
|
2009
|
tom 61 Supplement
At present, Norway spruce stands occupy 22% of the total forest area in Lithuania. Most of them are located in the northeastern highland (Žemaitija) and the central part of the country. 25% of the spruce-dominated stands are pure, the rest are mixed. Natural calamities like storms, droughts, and pests cause substantial damage and occur quite frequently. About 40 thousand ha of stands are cut after each storm. The mean wood yield of the spruce stands is 304 m3 ha-1, and the current annual increment is 6.2 m3 ha-1. The climatic conditions of Lithuania are variable enough to cause differentiation of habitats. For Norway spruce, 6 provenance regions have been established. The national gene conservation programme is based on (a) in situ genetic reserves, seed collection stands, and selected genotypes, and (b) ex situ clonal archives, seed orchards, experimental plantations, and gene bank collections. The present-day breeding of Norway spruce comprises family tests of populations for individual and population selection, and plans for inter-population hybrids. A strategy for Norway spruce breeding has been approved for the years 2004-2013. There is a genetically diverse material for future breeding: long-distance provenance tests, and population and family tests. Assessments of two provenance tests (aged 9 and 17 years) in central Lithuania revealed superior performance of central and northeastern Polish provenances: superior height, good stem quality, and late bud-burst in spring. This may be attributed to the favourable effect of transfer: avoidance of spring frosts (late bud-burst and good stem quality), and utilisation of the later part of the growing period for growth (late bud-set and superior height). Norway spruce is a climax species with different domestic and Darwinian fitness. Therefore, we suggest that the domestic fitness of local genotypes may be improved by introducing a few Polish clones in Lithuanian breeding populations.
5
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Stand structure and natural regeneration of Taxus baccata at "Stiwollgraben" in Austria

80%
Dhar A., Ruprecht H., Klumpp R., Vacik H.
Dendrobiology
|
2006
|
tom 56
19-26
English yew (Taxus baccata L.) is a rare tree species in Austria and gene conservation forests reserves are used to maintain English yew populations by silvicultural treatments. This paper describes the current situation of an English yew population at “Stiwollgraben”in Austria with regard to stand structure, vitality and natural regeneration. The area is one of the most important sites in Austria as it consists of 2236 yews.The vitality condition of the yew is very good, and more than 79% of the yews have been assessed as very vital to vital. The potentiality for natural regeneration (13019 one-year seedlings ha–1) is very high, but not all height classes are represented. This indicates a high survival ability of English yew at this site. Three different treatment strategies are described to maintain the yew population. The future effects of these treatments are discussed in the light of the environmental requirements of English yew.
6
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Strategy for long-term breeding of Picea abies in Lithuania: short overview

80%
Danusevicius D.
Dendrobiology
|
2009
|
tom 61 Supplement
This paper presents the newly suggested long-term breeding strategy for Norway spruce in Lithuania to share with the optimisation approach, which may be useful in synchronising the long-term breeding and gene conservation plans in neighbouring regions. The breeding programme in Lithuania is at a stage where the long-term plans need to be developed. Our strategy is to proceed with a closed-nucleus breeding population which is structured into subpopulations according to adaptation zones (4-5 subpopulations). The size of each subpopulation is 50 unrelated and progeny-tested individuals. The breeding cycle consists of double- pair mating and a balanced within-family selection forward. The candidates will be clone-tested. Advanced genotypes will be selected into an advanced nucleus; an isolated foreign breeding population is planned. Positive assortative mating is used for deployment. An experimental "shuttle-breeding" strategy may be tested: selection with avery high intensity, controlled crosses, nursery tests for vigour and growth rhythm, cloning by hedges into short-rotation clonal plantations.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.