88 research outputs found
The role of tree breeding in reforestation
This article focuses on the creation of seed sources for forest planting or seeding with a special focus on clonal seed orchards supporting planting Norway spruce and Scots pine in Sweden. Supporting long-term breeding and low input breeding is discussed. The focus is not on clonal forestry, although this is discussed. Natural regeneration is not dealt with and provenance choice only briefly. It is not a manual or literature review and focus on my own evaluations, but more detailed reviews can be found in the literature cited. It is intended to contribute some familiarity with many of the relevant genetic aspects on forest plantations
Bättre fröplantager för Sveriges framtid
• Huvuddelen av Sveriges framtida skogar börjar sitt liv i en fröplantage. Fröet blir genetiskt bra eftersom föräldrarna är kloner av utvalda träd. • Fröplantager är en reproducerbar och stabil frökälla, och fröet ger vanligen en snabbare och jämnare groning och jämnare plantkvalitet än beståndsfrö. • Fröplantager kan förväntas höja Sveriges uthålligt möjliga skogsavverkning med mer än 10 % i ett sekellångt perspektiv och med några procent i ett kortsiktigt perspektiv. • Användning av fröplantager möjliggör större framtida avverkningshöjningar än den sammantagna effekten av gödsling, dikning, klonskogsbruk, främmande trädslag och skogsodling på jordbruksmark tillsammans. • Klonantal på 20–25 verkar optimalt i framtida plantager. • De tidigaste fröskördarna efter anläggningen har inte fäder i plantagen, men går vanligen bra att använda ändå
Оптимизация энергопотребления электроплавильных печей с использованием технологий предварительного подогрева шихты
Материалы ХI Международной науч.-техн. конф. студентов, магистрантов и аспирантов [28-29 апреля 2011 г., г. Гомель]. - Гомель, 2011
Borrelia burgdorferi sensu lato in Ixodes ricinus ticks from Norway: evaluation of a PCR test targeting the chromosomal flaB gene
On the shape and likelihood of oceanic rogue waves
We consider the observation and analysis of oceanic rogue waves collected within spatio-Temporal (ST) records of 3D wave fields. This class of records, allowing a sea surface region to be retrieved, is appropriate for the observation of rogue waves, which come up as a random phenomenon that can occur at any time and location of the sea surface. To verify this aspect, we used three stereo wave imaging systems to gather ST records of the sea surface elevation, which were collected in different sea conditions. The wave with the ST maximum elevation (happening to be larger than the rogue threshold 1.25H s) was then isolated within each record, along with its temporal profile. The rogue waves show similar profiles, in agreement with the theory of extreme wave groups. We analyze the rogue wave probability of occurrence, also in the context of ST extreme value distributions, and we conclude that rogue waves are more likely than previously reported; the key point is coming across them, in space as well as in time. The dependence of the rogue wave profile and likelihood on the sea state conditions is also investigated. Results may prove useful in predicting extreme wave occurrence probability and strength during oceanic storms
New genetic loci link adipose and insulin biology to body fat distribution.
Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
Isozyme studies in seed orchards
Some applications of the isozyme technique for studies in seed orchards are discussed. The basis for these studies is the opportunity to use clones in the seed orchard which are isozymetically distinct from the others. If a clone ill one locus carries one or two alleles unique or rare to the orchard, it may then be possible to trace the contribution of this particular clone to the seed formation. The use of this method in studies on the net effect of open pollination in a seed orchard is pointed out. In the absence of such unique alleles for tile estimation of the pollination situation, another method is suggested. This method cart be made use of by collecting open-pollinated seeds from a clone and counting plants from these which, by means of the isozyme pattern, show a documented cross-pollination. In this way it is possible to obtain information on the occurrence of selfing. Checking of the isolation technique for controlled crosses is also possible with this isozyme technique. The theoretical opportunities for future studies of correlations between economically important traits and allozymes (allelic isozymes) are discussed briefly. The theoretical possibilities are partly illustrated by results obtained from Swedish Scots pine seed orchards. No indication of deviation from random mating were found. The frequency of plants originating from selfing following open pollination was indicated to be in the range of 2-5 per cent. Such plants seemed to be more common in the lower than in the upper part of the crowns of the ramets. The relevance of checking controlled crosses is demonstrated by means of an applied example
The relationship between self-fertilization, empty seeds and seeds originating from selfing as a consequence of polyembryony
The question of how to evaluate the relationship between self-fertilization, empty seeds and selfed seeds is discussed. Formulas are worked out, for different situations. The method of making calculations in the various cases is illustrared by examples. The following situations are considered: There is one embryo per ovule. There are two polyzygotic embryos per ovule-genetic death is caused by homozygosity of recessive embryonic lethals - the probability of genetic death is not correlated between embryos of the same ovule. The presence of polyembryony is of considerable importance for the relationship between the factors mentioned. Firstly, the situation where all outbred embryos are viable is considered and later the model is extended to the situation where outbred embryos are allowed to die
Germinability of Norway spruce and Scots pine pollen exposed to open air.
Germination of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) pollen decreased during exposure to open air conditions. Usually more than half of the pollen remained germinable after a few days outdoors, but following more than four days outdoors the germination became very low. This study supports the opinion that pollen in the atmosphere remains viable long enough to allow for long-distance gene flow by pollen migration, as an important factor in genetic management of conifers and in evolution, maintaining diversity and potential for adaptation
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