Offspring Of Trees Research Articles

Спадкові ознаки стійкості до кореневої губки сіянців сосни, вирощених із насіння дерев в осередках усихання

Pure pine stands, planted on formerly arable land, are usually infected by root rot caused by the basidiomycete fungus Heterobasidion annosum (Fr.) Bref. Currently, there are no radical methods to control the disease, despite more than 200 years of research throughout the world. Therefore, the alternative solution to this problem is the breeding of hyposensitive pine trees. The aim of the study was to identify the specificities of pine offsprings with various resistance to annosum root rot. The research was carried out in a 60-year-old pure pine stand within Kharkiv Region, infected by annosum root rot. According to the methodology of the study, trees were divided into three groups: «healthy» – no visible signs of damage outside the decline zone; «resistant» – in the open space of the gap in the disease focus without visible signs of disease; «diseased» – with signs of damage (weak growth, short pale green needles, etc.). The study of biometric parameters of the reproductive organs of Scots pine trees with various resistances to annosum root rot indicated that the disease-resistant trees had a greater average mass of a cone compared to infected and uninfected trees. Also, the mass of their 1,000 seeds was close to that of uninfected trees. In the diseased trees, these values were the least. Biometric characteristics of one-year pine seedlings grown in a greenhouse from seeds of «diseased», «healthy» and «resistant» trees showed that the characteristic feature of the one-year-old offspring of « resistant » trees grown within the root rot foci is a significantly longer root system of a seedling. Such a long root system allows it to survive under high disease background, which is probably the main criterion of pine resistance to the disease. Selected seedlings from the offspring of trees «resistant» to annosum root rot must comprise 20–30% of the planting material for afforestation. In order to grow root rot resistant pine stands, selected seedlings from the offspring of resistant trees are further recommended for the pine stand establishment on former arable land and reforestation of felling sites infected by root rot and gaps in the decline foci. Keywords: annosum root rot foci, root rot resistant trees, cones, seeds, seedling biometrics.

Higher resistance of the offspring of Scots pine trees resulting from natural regeneration in old foci of Heterobasidion annosum root rot

Heterobasidion annosum (Fr.) Bref. is a fungal pathogen causing annosum root rot – one of the most economically important diseases in coniferous stands. The major aim of this study was to compare the resistance of the offspring of Scots pine trees (Pinus sylvestris L.) from seed orchards and the offspring of trees that were naturally reproduced in old foci of the disease. In experiments conducted in vitro, we used 960 seedlings which were grown from seeds collected from 60 trees in 6 old foci of the disease and 640 seedlings grown from seeds collected in 4 seed orchards. The offspring of trees from seed orchards after inoculation with H. annosum had nearly twofold higher mortality rate than the seedlings developed from the seeds collected in old foci of the disease. This suggests that the offspring of self-sown trees in old foci of the disease has a greater, genetically conditioned resistance to annosum root rot.

Failure to migrate: lack of tree range expansion in response to climate change

AbstractTree species are expected to track warming climate by shifting their ranges to higher latitudes or elevations, but current evidence of latitudinal range shifts for suites of species is largely indirect. In response to global warming, offspring of trees are predicted to have ranges extend beyond adults at leading edges and the opposite relationship at trailing edges. Large‐scale forest inventory data provide an opportunity to compare present latitudes of seedlings and adult trees at their range limits. Using theUSDAForest Service's Forest Inventory and Analysis data, we directly compared seedling and tree 5th and 95th percentile latitudes for 92 species in 30 longitudinal bands for 43 334 plots across the eastern United States. We further compared these latitudes with 20th century temperature and precipitation change and functional traits, including seed size and seed spread rate. Results suggest that 58.7% of the tree species examined show the pattern expected for a population undergoing range contraction, rather than expansion, at both northern and southern boundaries. Fewer species show a pattern consistent with a northward shift (20.7%) and fewer still with a southward shift (16.3%). Only 4.3% are consistent with expansion at both range limits. When compared with the 20th century climate changes that have occurred at the range boundaries themselves, there is no consistent evidence that population spread is greatest in areas where climate has changed most; nor are patterns related to seed size or dispersal characteristics. The fact that the majority of seedling extreme latitudes are less than those for adult trees may emphasize the lack of evidence for climate‐mediated migration, and should increase concerns for the risks posed by climate change.