Shoot development and dieback in progenies of Nothofagus obliqua

Shoot growth and dieback were compared among progenies of nursery-grown seedlings of Nothofagus obliqua belonging to seven progenies of the same provenance (Quila-Quina, Argentina). First-year shoots consisted of one growth unit (GU) and second-year shoots of one or two GUs. The probability of development of two GU was similar for all progenies. Progenies were different in terms of shoot size, terminal bud abscission, the extent of shoot dieback after shoot extension and the node of origin of the relay shoot on the first shoot. Plants with a second-year shoot consisting of two GUs had a thicker stem and more nodes than those with single-GU shoots. The selection of N. obliqua seed trees based on architectural traits suitable for forestry development at specific sites must contemplate variability among progenies and their probabilities of successful development under different conditions.     

Phenology Differs among Norway Spruce Populations in Relation to Local Variation in Altitude of Maternal Stands in the Beskidy Mountains

An investigation of phenological and growth traits was conducted in a lowland plantation, comprised of 23 Norway spruce (Picea abies (L.) Karst.) seed stands from the Istebna region in the Beskidy Mountains of Poland. Significant differences were found among population in growth initiation, growth termination and the length of shoot elongation period. The two latter traits were highly correlated and were attributed to the altitude of the maternal stand. The tested populations were grouped based on phenology. Progeny of lower-alttitude stands ceased growth later, had a longer duration of shoot growth and greater current leader length compared to progeny of higher-altitude stands. Individual populations, however, did not differ in current-year growth and total tree height, implying higher within-population variation in growth traits than in phenology. The similar growth capacity of all tested populations suggests considerable gene flow between maternal stands, although differences in phenology imply the adaptation of progenies to the altitudinal environment of seed origin. These results suggest that within tested populations, selection is possible based on phenology alone, without considerable reduction of early height growth; final decisions, however, should be based on the environmental conditions of the planting site.     

Variation in seed traits and seedling vigour of <Emphasis Type="Italic">Cordia africana</Emphasis> Lam. provenances in Ethiopia

Cordia africana is a very important indigenous tree species for timber and other products and services in Ethiopia. Seed traits and seedling vigour of seeds from 12 provenances of the species were compared. Mean seed mass for each provenance was assessed for 1000 seeds in 10 replications, and seed length and width were measured for 100 seeds in four replications per provenance. Germination was assessed in a glasshouse taking 400 seeds from each provenance. Root collar diameter and height of 440 seedlings grown in a nursery for 290 days in Addis Ababa were measured. Seed length, seed width, seed mass, and shoot height and root collar diameter of seedlings showed significant differences (P < 0.001) among provenances. Correlation analysis between seed and seedling traits and environmental variables revealed significant positive correlations between seed width and germination percentage, seed width and altitude, seed width and longitude and seed length and latitude. Negative correlations were obtained between seed width and temperature, seed width and rainfall, seed mass and temperature, and germination and temperature of the seed source. As expected, differences in seed trait did not explain the variability in seedling vigour. Determining quantitative variations in seed traits and seedling vigour among provenances and the patterns along environmental gradients are essential for informing decisions on the tree improvement programme of the species.     

Family variation for fall cold hardiness in two Washington populations of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco)

In order to assess the genetics of fall cold hardiness in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco), shoot cuttings were collected in October from saplings (9-year-old trees) of open-pollinated families in two progeny tests in each of two breeding zones in Washington, one in the Coast range (80 families) and one on the west slope of the Cascade Mountains (89 families). Samples from over 5500 trees were subjected to artificial freezing and visually evaluated for needle, stem and bud tissue injury. The extent to which cold injury is genetically related to tree height and shoot phenology (timing of bud burst and bud set) was also evaluated.

Significant family variation was found for all cold hardiness traits; however, individual heritability estimates were relatively low (ranging from 0.09 to 0.22). Significant family-by-test site interaction was detected for needle injury in the Cascade breeding zone, but not in the coastal zone. Genetic correlations (r_A) among needle, stem and bud tissues for cold damage were weak (0.16 ≤ r_A ≤ 0.58) indicating that genes controlling fall hardening are somewhat different for different tissues. Timing of bud burst and bud set were only weakly correlated with cold injury (r_A ≤ 0.49). Thus, bud phenology is a poor predictor of fall cold hardiness in this species. There was no consistent relationship between tree height and cold injury in the coastal zone. In the Cascade zone, taller trees appeared to be more susceptible to cold injury, but the association was weak (mean r_A = 0.38, range 0.20 – 0.72).     

Genetic diversity and adaptive traits of European versus American Douglas-fir seedlings

Due to its productivity and potential to adapt to the expected climate change, the Douglas-fir is one of the most important commercial non-native forest tree species in Europe. Currently, seeds from both non-native European and native American seed stands are used for plantations. In this study, we investigate European seed lots for their native origin (variety and potential geographic origin in America) and assess the adaptability, growth and survival potential of European versus American Douglas-fir seed lots. We compare the genetic diversity, morphological characteristics such as height (h), root collar diameter (rcd) and the ratio of h/rcd, and the timing of bud burst. We investigate 852 1-year-old seedlings from 10 different US and European seed lots representing 5 provenance regions which are sold in Germany and Austria. Seedlings are genotyped for 13 nuclear SSRs and analysed together with reference data set and standard genetic structuring and assignment methods. Adaptive traits of morphological characteristics and timing of bud burst of the seedlings are recorded and statistically analysed. The results show that the investigated European seedlings originate from recommended American native seed sources and represent both varieties and inter-varietal admixed individuals. European seedlings have a lower genetic diversity versus the American seedlings and native populations. They show significant differences in the adaptive traits such as morphological characteristics and timing of bud burst. According to the genetic diversity indices, certified North American Douglas-fir seed sources should be preferred for planting in Central Europe.     

Inheritance of growth and survival in two 9-year-old,open-pollinated progenies of an advanced breeding population of Chinese firs in southeastern China

Tree growth traits (tree height, DBH and stem volume) and survival from two 9-year-old, open-pollinated progeny tests of Chinese fir were investigated for heritability, genotype × environment interaction, age-age genetic correlation and selection efficiency. The 97 and 79 families planted at two sites were collected from the third-cycle seed orchard. Individual heritability was estimated between 0.05 and 0.21 for tree height, DBH, and volume and between 0.45 and 1.0 for survival. Family heritability was between 0.20 and 1.14. Significant genotype × environment interaction was observed for the three growth traits. Type B genetic correlation was between 0.41 and 0.67 with an increasing trend as tree grows. High age-age genetic correlation was observed with correlation reaching 0.9 after age 4 for height, DBH, and volume. The genetic gains were estimated at 3.26, 3.39 and 5.98 % for tree height, DBH, and volume with 10 % selection intensity. The implication for advanced tree breeding in Chinese fir is discussed.     

Divergence among Masson pine parents revealed by geographical origins and SSR markers and their relationships with progeny performance

Predicting progeny performance from parental divergence would potentially enhance the efficiency of breeding. Thirteen clones of Masson pine (Pinus massoniana) were crossed in a 4 × 9 tester mating design and 36 full-sib families were generated. There were significant variations in major growth traits and heterosis of growth traits among the 36 full-sib families. A total of 115 alleles were detected with 30 sets of SSR primers. Genetic distances (GDs) among the crossed clonal pairs were calculated based on SSR data. Parental GDs was significantly correlated with all traits evaluated in the full-sib progeny test (P < 0.05), and the correlation coefficient was 0.398, 0.463 and 0.473 for tree height, DBH and wood volume. Parental geographical divergence was also significantly correlated with growth traits of progeny, while the correlation coefficient was lower than that of GDs. These results demonstrated the potential and feasibility of SSR markers for predicting progeny performance of Masson pine. Considering the influence of genotype × environment interaction effect on the stability of full-sib family performance, our results regarding the moderate contribution of parent GDs in predicting the performance of their full-sib progenies is of importance mainly for the specific region where the progeny test was carried out.     

Inter- and intra-provenances variations in seed size and seedling characteristics of Khaya senegalensis A. Juss in Burkina Faso

Within- and between-provenance variations in seed and seedling traits of Khaya senegalensis A. Juss were studied at INERA in Burkina Faso. Nursery grown seedlings from four provenances in Burkina Faso were used for the study. The studies revealed significant variability in all traits evaluated. Seed length and weight significantly varied among provenances and families within provenances, where Bopiel and Koyenga had the highest mean values. Height and root collar diameter of 1 year old seedlings significantly varied among families within provenances. Except leaf biomass ratio and carbon isotope ratio which varied significantly among provenances but not among families within provenances, all other seedling biomass traits—total plant biomass, stem biomass ratio, leaf biomass ratio, root biomass ratio, root shoot ratio, specific leaf area, and leaf area ratio were significantly affected by provenances and families within provenances. The magnitude of variation due to family effect ranged from 65 to 93 % for seed size traits, and from 4.5 to 17.8 % for seedling characters. Estimates of family heritability were moderate to high (0.67–0.95) for seed traits, but low to moderate (0.19–0.59) for seedling characters, indicating that much of the total variation in seed traits is due to the genetic effect. The two most prominent provenances, Koyenga and Bopiel, with higher seed size and greater seedling growth could be considered for an eventual K. senegalensis improvement program in Burkina Faso.     

Biogeographic differences in cone, needle and seed morphology among natural Picea asperata populations in Western China

This study represents a geographical approach to morphological variation of cones, needles and seeds in natural dragon spruce (Picea asperata Mast.) populations across western China and the relationship between morphological traits and weather variation for the origins of populations. Significant differences were found for all cone, needle and seed traits among populations and trees within populations. The coefficients of variation in 2 higher latitude populations were higher than those in other populations in all traits except for needle width and seed width. Fairly high within-population variability was also detected for cone dry weight, seed dry weight and needle traits in this study. Cone length, cone width, cone dry weight, seed scale length, seed scale width and seed wing length were strongly positively intercorrelated. Seed length and seed dry weight showed a significantly positive correlation with seed wing length. And needle width showed a significant negative correlation with cone traits, seed scale length, seed wing length and seed length. The higher the annual mean temperature, the higher the average cone length. This study also revealed a negative linear dependence on latitude: the higher the latitude, the lower the population average seed length. Seed dry weight was positively and linearly related with altitude.     

Interactions between climate,growth and seed production in Spanish black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> Arn. ssp. <Emphasis Type="Italic">salzmannii</Emphasis>) forests in Cuenca Mountains (Spain)

Tree growth is regulated by a combination of exogenous and endogenous factors. Such factors also interact with each other, complicating the understanding of causal links. IN particular, resource allocation is sensitive to reproductive investment, especially in masting species, which in turn is regulated by climatic variables. Both resource allocation and seed production patterns are also sensitive to tree age. This study aims to (1) evaluate the effects of tree age and local and regional climate on tree ring width and seed production by Spanish black pine (Pinus nigra Arn. ssp. salzmannii) forest in Cuenca Mountains (Spain), and (2) assess the relationship between seed production and secondary growth of Spanish black pine. Seed fall was estimated using 60 rectangular seed traps (40 × 50 × 15 cm) from 2000 to 2014, randomly distributed across the study area. Standardized tree-ring chronologies were calculated using a random sample of 106 trees stratified into three age classes (> 80 years; 26–80 years, and ≤ 25 years). Local climate data was obtained from a meteorological station, and regional climate data from the CRU-TS 3.1 dataset. Average seed production ranged over time from 2 to 189 seeds m^?2 (coefficient of variation = 157%). We identified four masting years (2000, 2003, 2006, and 2014) using a classification based on percentile seed production. Seed production was regulated by climate of the previous 2–3 years, while tree growth responded to precipitation and temperature in the previous and current year. Independent of climate, high seed production had a negative effect on tree ring width and weakened climate growth relationships, indicating resource depletion. Tree age modulated climate sensitivity, increasing correlations between climate and tree-ring index in older trees. P. nigra has been showed to be a climate sensitive species with a bimodal masting behaviour, which should be taking into account for management purposes and silvicultural guidelines under climate change scenarios.     

Needle growth in Sitka spruce (Picea sitchensis): effects of nutrient deficiency and needle position within shoots

Needle development and shoot growth were studied in 14- and 20-year-old Sitka spruce (Picea sitchensis (Bong.) Carr.) planted on an oligotrophic peat and fertilized with N, P and K (control), N and P (-K), N and K (-P) or unfertilized (-NPK). Shoot extension, needle number, and the size and number of needle cells were observed throughout the season. Beginning with bud burst in early May, needle growth continued for nine weeks in the control treatment. Needle growth in the mineral deficiency treatments terminated at the same time as in the controls, although it did not begin until up to three weeks later than in the control trees. Needles developed acropetally along the shoot, with basal needles completing their development first. Cell division in needles of control trees lasted about 3 weeks, with cell expansion continuing for a further 3 weeks. Initial mean cell cycle times were shortest for proximal needles following bud burst, but lengthened as the season progressed. Cell number increased from 6600 in the primordia to 200 000 in mature needles. Final needle dimensions and cell number varied according to the position of the needle on the shoot. The largest needles with the most cells were near the middle of the shoot. Relative to the controls, all mineral deficiency treatments reduced shoot length, bud and needle dimensions, and needle cell number, particularly the -P treatment. Potassium and P deficiency treatments reduced primordial cell number by up to 42%, whereas final mean cell size was 30% greater in the -P treatment, 17% greater in the -NPK treatment, but 14% smaller in the -K treatment. Mean cell size was constant for needles at all positions in any particular treatment at any time, so that final needle size was determined by cell number alone. Needle dry weight/fresh weight ratio continued to increase until early August, with significantly higher ratios in the -K and -P treatments than in the controls.     

Realized genetic gain observed in second-generation seedling seed orchards of <Emphasis Type="Italic">Acacia mangium</Emphasis> in South Kalimantan,Indonesia

Realized genetic gains brought by the first-generation tree improvement of Acacia mangium were evaluated by analyzing the 1-year growth performance of growth (height, dbh) and form (stem straightness, multi-stem) traits using data collected from three second-generation orchards: groups B, C, and D. Each orchard was composed of improved families derived from open-pollinated seed of plus trees selected from the first-generation seed orchards and newly added unimproved families collected from the same geographic region. The number of improved families and that of the unimproved in each orchard were 31 and 23 for group B, 28 and 39 for group C, and 24 and 30 for group D. Gains were calculated as percentage increase of improved families over unimproved ones. Improved families performed better than unimproved ones in 11 out of 12 comparison cases: four traits each in the three orchards. Averages of the realized genetic gain across the three seedling seed orchards were 3.1%, 5.2%, 4.3%, and 0.5% for height, dbh, stem straightness, and multi-stem, respectively. Except for multi-stem, the performances of improved families were significantly better than those of unimproved families in all the three orchards for dbh and in two out of three orchards for height and stem straightness.     

Phenotypic Differences Between Natural and Selected Populations of Picea Abies. II. Apical Mitotic Activity and Growth Related Parameters

Apical mitotic index (MI) and growth of non-juvenile Norway spruce [Picea abies (L.) Karst.] populations growing in northern Sweden (63°54' N) were monitored in 1996. Annual leader shoot lengths and shoot growth components for the period 1990-1997 were measured in 1997. In 1997 populations transferred more than approximately 3° in latitude were found to be shorter than local populations. MI levels were initially high in all populations in mid-April. In spring, populations originating north of 63°30' N showed higher MI levels, and started shoot growth earlier, than populations originating further south. In autumn, MI levels were higher in populations originating south of 63°30' N than in populations originating further north and higher in seed orchard populations than in natural populations of similar latitudinal origin. The number of stem-units (NSU) was correlated with tree height and leader shoot length. NSU and elongation of stem-units appeared to be primarily influenced by summer temperature. Prolonged MI activity in autumn did not result in high NSU but appeared to be associated with a higher risk of frost damage to buds. The results are discussed in relation to climatic factors, seed transfer, selection and inherent growth rhythms.     

Phenotypic changes in progenies of northern clones of Picea abies (L.) Karst. grown in a southern seed orchard

Results are presented from three different field trials comparing controlled crossed materials of Norway spruce from the southern seed orchard at Lyngdal (58° N) with open‐pollinated progenies from the same mother trees standing in the northern natural forest (63–66° N). The seed orchard progenies flushed consistently later in the spring, terminated leader shoot growth later in the summer, had higher frequencies of lammas shoots, were delayed in lignification during autumn, and were 15% taller at age seven years from seed. The difference between the orchard‐ and the natural stand material appeared to be permanent from age four to age seven. It is suspected that the non‐native environment in the seed orchard could affect the genotypic performance of the seed orchard progenies.     

Evidence that the negative relationship between seed mass and relative growth rate is not physiological but linked to species identity: a within-family analysis of Scots pine

Seed mass and relative growth rate (RGR) are important determinants of early seedling growth, and hence seedling establishment. Although a positive interspecific relationship between seed mass and seedling dry mass is well established, much less is known about the relationships among seed mass, seedling mass and RGR within species. We examined relationships among seed mass, seedling mass and RGR within and among maternal plant lines of Scots pine (Pinus sylvestris L.). To assess the effects of seed mass and maternal origin on RGR, individual seeds from two seed crops (years 2004 and 2005) of ten maternal plants growing under nursery conditions were weighed and then germinated. Seed mass was strongly determined by maternal plant, and seedling mass was largely determined by seed mass, with a positive correlation between these variables both across and within maternal plants. In contrast, RGR was weakly related to seed mass, with no consistent pattern in the sign of the relationship. It is well known that species differ in RGR and that RGR is related to seed mass across species. Lack of consistent evidence for this relationship within maternal lines, and for Scots pine overall, suggests that the relationship is not directly causal, but reflects consistent evolutionary covariation in these two physiologically independent traits.     

杉木遗传变异组成试析

70年代以来,我国杉木遗传改良工作已发生了根本性的变化,不仅在生态造林区已相继选育出了一批速生型的优良家系、优良种源和优良无性系,而且还不同程度地在生产中得到了推广应用,取得了显著的经济效益。近年来,有关杉木多世代育种的探讨已有不少报道,但立论于遗传变异基础上,纵贯从群体到个体,综合多性状变异相关的见解却不多见,其主要原因或许是有意识地设置这方面的试验还显得不足之故。为此,我们在承担全国杉木协作     

Genetic Variation and Phenotypic Plasticity of Quercus robur Populations and Open-pollinated Families in Lithuania

The purpose of the study was to estimate among- and within-population variation for juvenile growth and for growth rhythm traits, bud flushing and leaf colouring, in open-pollinated families of Quercus robur L. from six Lithuanian populations under different environmental conditions. Assessments were done in the nursery up to 4 yrs, and after replanting in three field trials at the age of 6 yrs. A highly significant population effect was found for bud flushing. Large family variance components were estimated for bud flushing and height. The family×site interaction was significant and more pronounced for growth cessation and height than for bud flushing. Depending on the trait, from 13 to 33% of families contributed significantly to the family×site interaction. Strongly significant site×population interaction was estimated only for bud flushing. Families with early bud flushing were taller, although the correlation was weak. Correlations between family means in bud flushing and bud flushing of parent trees varied from 0.53 to 0.60. Large CV_A estimates for the adaptive traits suggest that species have a potential to adapt to environmental changes that may occur from global warming and indicate good perspectives for gene conservation and tree breeding when using Multiple Population Breeding System.     

Parental participation in progeny and effective population sizes in experimental seed orchards of wild cherry Prunus avium L. (Batsch)

Parents and progenies genetic diversity, and male and female contributions to the seed crop were assessed in three experimental Prunus avium seed orchards. Collected data were used to compare different effective population sizes, based on phenological, seed crop and paternity analysis. Our results did not show any difference of genetic diversity between parents and progenies. A limited pollen pollution was detected. We showed that distance and coflowering among clones had a significant effect on effective pollination, and a significant effect of the production of flowers was revealed in one of the seed orchards. Our study also revealed a quite low number of effective size of fathers per mother, but high effective sizes of mothers, fathers and parents at the level of the seed orchard. Finally, the calculation of effective size of mothers, fathers and parents was not highly modified when having the complete information based on the paternity analysis.     

Pollen dispersal,mating patterns and pollen contamination in an insect-pollinated seed orchard of <Emphasis Type="Italic">Schima superba</Emphasis> Gardn. et Champ.

Pollen flow and mating patterns are the most important factors influencing the genetic structure of insect-pollinated forest trees and are essential parts of genetic management in seed orchards. We investigated pollen flow, the mating system and the level of pollen contamination in a clonal seed orchard of Schima superba Gardn. et Champ. In total, 328 open-pollination progenies coming from 11 mother trees were identified using 13 polymorphic microsatellite loci. A total of 203 full-sib families were identified and were nested among the 11 studied seed donors. The male reproductive success rate from 0.49 to 7.77% for most male parents, with an average of 2.44%. More than 80% of the crosses were found within a distance of 60 m, and the most frequent pollination distance between female parent and male parents was approximately 20 m. Mating system analysis showed that the outcrossing level was very high (t _m  = 1.000, outcrossing rate = 98.5%) in the seed orchard and that there was an average of 2.3 effective pollen donors (N _ep ) per female parent. In addition, the mating success of individual males within neighborhoods was moderately influenced by their fecundity and the direction of their location relative to mother trees. The pollen contamination from outside the seed orchard was high (7.01%). Our findings are valuable for the assessment of seed orchards, and it may be worthwhile to use pollen management strategies to decrease pollen contamination and increase the genetic quality of the seeds produced.     

Variation in seed morphometric characters,oil content and azadirachtin content of seeds,in vitro shoot cultures and callus cultures among different populations of <Emphasis Type="Italic">Azadirachta indica</Emphasis>

We studied seed morphometric characters, oil content and azadirachtin content in a medicinally important and insect repellent tree species Azadirachta indica A. Juss. Ten populations were selected from two central Indian states of Madhya Pradesh and Chhattisgarh and twenty candidate plus trees were selected from each population based on tree attributes. Azadirachtin content was estimated in seeds, in vitro shoots and callus cultures through HPLC. Significant variation (p < 0.05) was observed in seed morphometric characters, oil content and azadirachtin content among the ten populations. Maximum value for 100 seed weight was obtained in seeds of Raigarh (30.51 g) which was on par with seeds of Bargi (28.37 g) and Chhatarpur (26.36 g). The ratio of highest kernel to seed was also obtained in seeds of Raigarh (60.11%). Kernels from Chhatarpur population recorded the highest oil content (24.20%), which was equal to that in Sihore (23.75%) and Katni (21.75%). We recorded highly significant variation in azadirachtin content in seed samples, in vitro shoot samples and callus cultures. Maximum azadirachtin was present in the seeds of Gwalior (0.882%) which was on par with azadirachtin content in seeds of Chhatarpur, Katni, Sihore, Shahdol and Chhindwara. Maximum azadirachtin in the in vitro shoots was present in the cultures of Gwalior (0.218%) which was statistically on par with Sihore (0.176%). Similarly, in callus cultures of nodal segments maximum azadirachtin was recorded in the Gwalior population (0.033%) which was statistically on par with Sihore (0.028%). The trees of Gwalior and Sihore populations can be produced in large numbers through vegetative propagation to obtain seeds with higher azadirachtin content.