The main objective of the study was to estimate and compare genetic parameters in the widespread ... more The main objective of the study was to estimate and compare genetic parameters in the widespread forest tree species Betula pendula, Alnus glutinosa and Quercus robur in Lithuania. The results were based on assessments of half-sib progeny at juvenile age in field trials located in different eco-geographic regions. Bud flushing and height were measured at ages 4 to 9. Population and family variance components for both traits were the largest in pedunculate oak, whereas genotype × environment interaction estimates were large in black alder. Within a trait, genetic correlations were strong for bud flushing in silver birch and pedunculate oak. The estimates for height were medium to strong only in pedunculate oak, while they were very weak to weak for the other two species. The strong population effects in pedunculate oak indicate that a larger number of populations needs to be selected for gene conservation than in the other two species. The clinal variation in adaptive traits in black...
ABSTRACT Totally 101 half-sib progeny family from 24 Lithuanian silver birch (Betula pendula Roth... more ABSTRACT Totally 101 half-sib progeny family from 24 Lithuanian silver birch (Betula pendula Roth.) populations were studied at age 8 in three field trials.. From 5 to 6 families represented each population. The field trials are situated in two silver birch provenance regions or three ecoclimatic regions. The measurements or assessments were done on adaptive (bud flushing or growth start and autumn leaf yellowing or growth cessation) and productivity (height and diameter) traits. The estimates of genetic variation, genotype x environment interaction (G x E), heritability and additive genetic coefficient of variation (CVA) are presented. CVA estimates for separate trials were 8.7-10.9 % for height, 15.2-18.8 % for stem diameter, 8.9-34.2 % for bud flushing and 7.6-15.9 % for growth cessation. Almost 32 % of families significantly differed in their ecovalences for height, 21 % for stem diameter, 9 % for bud flushing, 42 % for growth cessation. Additive genetic variation found within populations let us presume that species has potential to adapt genetically by natural or artificial selection to climate change. Keywords: silver birch, half-sib progeny families, populations, genetic diversity, G x E interaction, adaptive traits, heritability.
Periodic occurrences of decline and dieback of oak stands over widespread areas in Lithuania and ... more Periodic occurrences of decline and dieback of oak stands over widespread areas in Lithuania and in neighbouring countries give raise a serious concern about possibility to conserve oak genetic resources and implement the oak breeding programs. More detailed information about the magnitude of genetic diversity of the main forest tree species in Lithuania is still absent. The necessity to preserve adaptive genetic potential and to increase the effectiveness of breeding under hardly predictive climate changes calls for detailed research of genetic resources. 28 Lithuanian oak populations were sampled and chloroplast DNA (cpDNA) was determined using PCR-RFLP markers. Totally 4 haplotypes were detected. One of the aims of our study was also to check if exist some association at population level between haplotype and phenotypic traits. Totally, 14 phenotypic traits that were measured in sample plots in oak stands, including health status traits and 5 acorn traits have been analysed. Pear...
ABSTRACT Half-sib progeny families from three common ash (Fraxinus excelsior) populations were in... more ABSTRACT Half-sib progeny families from three common ash (Fraxinus excelsior) populations were investigated by exposing them to different ozone dosage in the climatic chambers. There was no significant impact of different ozone doses on tree height, diameter and height increment, and only leaf damage traits gave significant results (P<0,001). Influence of genetic factors – populations and families – was significant only for height increment. Ozone treatment resulted in height differences between populations becoming significant and reaching 30 % one year later. Significance of the population x ozone treatment interaction shows varying population response to ozone, though other traits studied did not show significant interaction. Family variance component was high enough (24.5%) for tree height, but low for diameter (7.7%) and height increment (6.1%) and was not detected for leaf damage traits. Leaves of some trees in different families remained undamaged even in the treatment with highest ozone dosage (240 µg/m3), indicating pronounced individual genetic differences. Exposure to ozone has decreased height genetic variation (CVA): from 47.6-49.4% in control variant to 10.7-30.8% in ozone treatment with 240 µg/m3. The most drastic decrease was observed in Šilutė population. Under ozone treatments, three highest families in this population did not reach the height obtained in control variant. Different populations and families have demonstrated differing response to ozone by alteration of traits and its genetic variation. Such alteration due to stressors at juvenile age may influence adaptation, sustainability and competitive ability of newly forming populations. Keywords: Fraxinus excelsior, populations, progeny, half-sib families, ozone, genetic variation.
ABSTRACT Conservation of genetic diversity is the key issue in sustainable conservation of biodiv... more ABSTRACT Conservation of genetic diversity is the key issue in sustainable conservation of biodiversity. The prime objective for gene conservation should be defined a creation of favourable conditions for continuous adaptation and evolution of the species. The Multiple Population Breeding system (MPBS) would be applicable with high efficiency for conservation of English oak in Lithuania. Keywords: forest gene resources, dynamic gene conservation, tree breeding, MPBS, Quercus robur.
The study aimed the evaluation of genetic features of populations and genetic variation of adapti... more The study aimed the evaluation of genetic features of populations and genetic variation of adaptive traits and RAPD markers of open pollination progenies from Lithuanian and western European populations of Fraxinus excelsior in field trials, established in three different provenance regions of Lithuania. Progenies of the Lithuanian populations had earlier bud flushing and better health condition than progenies of western European populations in all three trials, but tree height was smaller (except the Šilutė population). Genetic effects at population and family levels were significant for all traits studied. Although family variance component was not high reaching from 11.6 to 22.6%, the additive coefficient of genetic variation was high ranging from 30.3 to 36.8% in separate field trials. Genetic variation of adaptive traits and RAPD markers did not correlate in most populations, thus indicating its differing adaptive potential. The Šakiai and Kupiškis populations had high genetic ...
Phenogenetic response of silver birch populations and half-sib families to separate and combined ... more Phenogenetic response of silver birch populations and half-sib families to separate and combined elevated ozone (O(3)) concentrations and ultraviolet-B (UV-B) radiation dozes was studied at juvenile age in the climatic chambers. Significant population and family effects were found for seedling height, lamina width, and leaf damage. The exposure to UV-B radiation decreased genetic variation at the stage of seed germination. Complex exposure to UV-B and O(3) caused an increase of genetic variation at the stage of intensive seedling growth: seedling height genetic variation in separate treatments increased from 23.7-38.6 to 33.7-65.7%, the increase for lamina width was from 10.2-13.9 to 13.6-31.8%. Different populations and families demonstrated differing response to elevated complex UV-B and O(3) exposure. Changes of genetic intra-population variation were population-specific. Such changes in genetic variation under the impact of stressors can alter adaptation, stability, and competitive ability of regenerating populations in a hardly predictive way.
The main objective of the study was to estimate and compare genetic parameters in the widespread ... more The main objective of the study was to estimate and compare genetic parameters in the widespread forest tree species Betula pendula, Alnus glutinosa and Quercus robur in Lithuania. The results were based on assessments of half-sib progeny at juvenile age in field trials located in different eco-geographic regions. Bud flushing and height were measured at ages 4 to 9. Population and family variance components for both traits were the largest in pedunculate oak, whereas genotype × environment interaction estimates were large in black alder. Within a trait, genetic correlations were strong for bud flushing in silver birch and pedunculate oak. The estimates for height were medium to strong only in pedunculate oak, while they were very weak to weak for the other two species. The strong population effects in pedunculate oak indicate that a larger number of populations needs to be selected for gene conservation than in the other two species. The clinal variation in adaptive traits in black...
ABSTRACT Totally 101 half-sib progeny family from 24 Lithuanian silver birch (Betula pendula Roth... more ABSTRACT Totally 101 half-sib progeny family from 24 Lithuanian silver birch (Betula pendula Roth.) populations were studied at age 8 in three field trials.. From 5 to 6 families represented each population. The field trials are situated in two silver birch provenance regions or three ecoclimatic regions. The measurements or assessments were done on adaptive (bud flushing or growth start and autumn leaf yellowing or growth cessation) and productivity (height and diameter) traits. The estimates of genetic variation, genotype x environment interaction (G x E), heritability and additive genetic coefficient of variation (CVA) are presented. CVA estimates for separate trials were 8.7-10.9 % for height, 15.2-18.8 % for stem diameter, 8.9-34.2 % for bud flushing and 7.6-15.9 % for growth cessation. Almost 32 % of families significantly differed in their ecovalences for height, 21 % for stem diameter, 9 % for bud flushing, 42 % for growth cessation. Additive genetic variation found within populations let us presume that species has potential to adapt genetically by natural or artificial selection to climate change. Keywords: silver birch, half-sib progeny families, populations, genetic diversity, G x E interaction, adaptive traits, heritability.
Periodic occurrences of decline and dieback of oak stands over widespread areas in Lithuania and ... more Periodic occurrences of decline and dieback of oak stands over widespread areas in Lithuania and in neighbouring countries give raise a serious concern about possibility to conserve oak genetic resources and implement the oak breeding programs. More detailed information about the magnitude of genetic diversity of the main forest tree species in Lithuania is still absent. The necessity to preserve adaptive genetic potential and to increase the effectiveness of breeding under hardly predictive climate changes calls for detailed research of genetic resources. 28 Lithuanian oak populations were sampled and chloroplast DNA (cpDNA) was determined using PCR-RFLP markers. Totally 4 haplotypes were detected. One of the aims of our study was also to check if exist some association at population level between haplotype and phenotypic traits. Totally, 14 phenotypic traits that were measured in sample plots in oak stands, including health status traits and 5 acorn traits have been analysed. Pear...
ABSTRACT Half-sib progeny families from three common ash (Fraxinus excelsior) populations were in... more ABSTRACT Half-sib progeny families from three common ash (Fraxinus excelsior) populations were investigated by exposing them to different ozone dosage in the climatic chambers. There was no significant impact of different ozone doses on tree height, diameter and height increment, and only leaf damage traits gave significant results (P<0,001). Influence of genetic factors – populations and families – was significant only for height increment. Ozone treatment resulted in height differences between populations becoming significant and reaching 30 % one year later. Significance of the population x ozone treatment interaction shows varying population response to ozone, though other traits studied did not show significant interaction. Family variance component was high enough (24.5%) for tree height, but low for diameter (7.7%) and height increment (6.1%) and was not detected for leaf damage traits. Leaves of some trees in different families remained undamaged even in the treatment with highest ozone dosage (240 µg/m3), indicating pronounced individual genetic differences. Exposure to ozone has decreased height genetic variation (CVA): from 47.6-49.4% in control variant to 10.7-30.8% in ozone treatment with 240 µg/m3. The most drastic decrease was observed in Šilutė population. Under ozone treatments, three highest families in this population did not reach the height obtained in control variant. Different populations and families have demonstrated differing response to ozone by alteration of traits and its genetic variation. Such alteration due to stressors at juvenile age may influence adaptation, sustainability and competitive ability of newly forming populations. Keywords: Fraxinus excelsior, populations, progeny, half-sib families, ozone, genetic variation.
ABSTRACT Conservation of genetic diversity is the key issue in sustainable conservation of biodiv... more ABSTRACT Conservation of genetic diversity is the key issue in sustainable conservation of biodiversity. The prime objective for gene conservation should be defined a creation of favourable conditions for continuous adaptation and evolution of the species. The Multiple Population Breeding system (MPBS) would be applicable with high efficiency for conservation of English oak in Lithuania. Keywords: forest gene resources, dynamic gene conservation, tree breeding, MPBS, Quercus robur.
The study aimed the evaluation of genetic features of populations and genetic variation of adapti... more The study aimed the evaluation of genetic features of populations and genetic variation of adaptive traits and RAPD markers of open pollination progenies from Lithuanian and western European populations of Fraxinus excelsior in field trials, established in three different provenance regions of Lithuania. Progenies of the Lithuanian populations had earlier bud flushing and better health condition than progenies of western European populations in all three trials, but tree height was smaller (except the Šilutė population). Genetic effects at population and family levels were significant for all traits studied. Although family variance component was not high reaching from 11.6 to 22.6%, the additive coefficient of genetic variation was high ranging from 30.3 to 36.8% in separate field trials. Genetic variation of adaptive traits and RAPD markers did not correlate in most populations, thus indicating its differing adaptive potential. The Šakiai and Kupiškis populations had high genetic ...
Phenogenetic response of silver birch populations and half-sib families to separate and combined ... more Phenogenetic response of silver birch populations and half-sib families to separate and combined elevated ozone (O(3)) concentrations and ultraviolet-B (UV-B) radiation dozes was studied at juvenile age in the climatic chambers. Significant population and family effects were found for seedling height, lamina width, and leaf damage. The exposure to UV-B radiation decreased genetic variation at the stage of seed germination. Complex exposure to UV-B and O(3) caused an increase of genetic variation at the stage of intensive seedling growth: seedling height genetic variation in separate treatments increased from 23.7-38.6 to 33.7-65.7%, the increase for lamina width was from 10.2-13.9 to 13.6-31.8%. Different populations and families demonstrated differing response to elevated complex UV-B and O(3) exposure. Changes of genetic intra-population variation were population-specific. Such changes in genetic variation under the impact of stressors can alter adaptation, stability, and competitive ability of regenerating populations in a hardly predictive way.
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