Inheritance pattern and genetic correlations among growth and wood quality traits in Para rubber tree (Hevea brasiliensis) and implications for breeding

Specific gravity exhibits extremely large radial increases with distance from the pith in Heliocarpus appendiculatus Turcz. (Tiliaceae), a pioneer of neotropical wet forests. To determine some of the wood anatomical changes associated with this increase, wood samples taken at breast height from three trees were divided into 1.0‐cm‐long segments from pith to bark. Measurements were made of fiber wall thickness, fiber lumen diameter, and percentages of fibers, axial parenchyma, ray parenchyma, and vessels on sections prepared from each segment. The extreme radial increases in specific gravity were associated with increases in fiber wall thickness, decreases in fiber diameter, decreases in fiber lumen diameter, and changes in the relative proportions of fibers and parenchyma. The increase in percent fiber concomitant with a decrease in axial parenchyma was the most important contributor to the increase in specific gravity in this species. The best predictor of specific gravity was percent fibers (r = 0.91, 0.92, 0.94) or percent axial parenchyma (r = ‐0.92, ‐0.91, ‐0.95), two variables that were highly intercorrelated (r = ‐0.95, ‐0.98, ‐0.99).

Sustainable pulpwood production from fast-growing tree plantations is needed for pulp and paper industries. To increase the pulpwood production efficiency, the anatomical characteristics and derived-wood properties of 75 trees from 15 half-sib families of Eucalyptus camaldulensis Dehnh. planted in Thailand were investigated, and then the family was classified by suitability of wood as raw material for pulp and paper products using principal component analysis and clustering. The mean values of vessel diameter, vessel frequency, fibre diameter, fibre lumen diameter, and fibre wall thickness at 2 cm from the cambium were 128 µm, 16 no./mm2, 11.1 µm, 7.1 µm, and 1.88 µm, respectively. In addition, the Runkel ratio, Luce’s shape factor, flexibility coefficient, slenderness ratio, solids factor, and wall coverage ratio (i.e., derived-wood properties) were 0.53, 0.42, 0.64, 85.3, 68 × 103 µm3, and 0.34, respectively. Significant differences in fibre diameter, fibre lumen diameter, and Runkel ratio were found among families. Although significant differences among families were not found for other anatomical characteristics and derived-wood properties, the p-values obtained by an analysis of variance test ranged from 0.050 to 0.088. Based on the results of a principal component analysis and cluster analysis, 15 families were classified into four clusters with different expected pulp and paper characteristics. The suitability of wood from E. camaldulensis half-sib families for pulp and paper can be evaluated by principal component analysis using anatomical characteristics and physical properties as variables. Based on the results, desirable pulp and paper quality may be obtained through the selection of families from this species.

The variable environmental conditions of the Amazon forest can affect the wood properties of the tree species distributed across its diverse phytophysiognomies. Carapa guianensis (Andiroba) occurs in upland and floodplain forests, and the wood and oil of its seeds have multiple uses. The aim of this study was to evaluate the wood properties of C. guianensis trees in upland and estuarine floodplain forests of the Amazon River. Eight trees were selected, with four being from the upland and four from the floodplain forests. The fiber length, fiber wall thickness, vessel diameter and frequency, microfibril angle, specific gravity and wood shrinkage were evaluated. The juvenile and mature wood zones were determined according to these variables. The fiber length, fiber wall thickness and specific gravity increased, and microfibril angle decreased, in the pith to bark direction. Only the fiber length variable was efficient for delimiting juvenile, transition and mature wood. The fiber length, wall thickness and specific gravity of wood were higher in upland forest trees. However, the environment did not alter the beginning of the formation and proportion of C. guianensis mature wood. This information is important for the log fit in cutting diagrams, aiming toward improving the production, classification and processing of pieces with specific quality indexes in order to direct them to appropriate wood uses.

The performance and variability patterns in the wood element’s dimensions, specific gravity and growth parameters namely ramet height and GBH were evaluated in 16 clones of parents, F1 and F2 hybrids of Populus deltoides Bartr. ex Marsh. Ramet radial variations were non-significant, while inter-clonal variations due to interaction of clone/replication were significant for all the wood traits except vessel element length. Inter-clonal variations were significant only for fiber length and fiber wall thickness. Fiber length and specific gravity were significantly higher in female, while wall thickness and vessel element length were higher in male clones. Female parents (G48 and S7C8) showed higher fiber length and specific gravity than of the male parent (G3), while vessel diameter and wall thickness were higher in male parent (G3). There is not much difference in fiber length and vessel element’s dimensions among the parents, F1 and F2 generation hybrid clones. Specific gravity did not showed any trend for parents, F1 and F2 generations. Generally female clones showed higher growth rate. Broad sense heritability for wood traits ranged from 0.143 (fiber length) to 0.505 (fiber wall thickness), while for growth traits it was 0.374 (GBH) and 0.418 (height). Genetic gain for all the wood and growth traits was positive for most of the wood traits. The highly divergent male clone (78) and female clones (S7C8, G48, W/A 49) in number of combinations could be used for developing new hybrids of desired wood traits to develop new clones.

Three trees were randomly selected from each age, The trees were felled and one disc 5cm. in thickness were taken from DBH in each selected tree to study the anatomical properties namely; fiber length، fiber diameter, fiber wall thickness, the ratio of double fiber wall thickness to lumen diameter (Runkel ratio) and the ratio of fiber length to its diameter. From each disc a sector was taken from the pith to the bark and divided into three equal parts to study the variation in anatomical properties across the stem.Average fiber length of the young trees (1.03mm), while (1.00mm) for the mature trees.Analysis of variance showed no significant difference between the trees for all the anatomical properties in this study for both ages. Analysis of t test showed that there was no significant difference between the average of fiber length to its diameter، While there is significant difference between fiber wall thickness, fiber lumen diameter and the Runkel ratio.The results did not shows any regular concerning the variation of fiber dimension in the radial direction .It was shown that there is a significant increase in the fiber length for each ages and in the fiber wall thickness and the Runkel rtio for the mature trees. There were an increase from the pith to the middle then not significant increase for the fiber diameter and the Runkel ratio for the young trees but it is significant for the ratio of fiber length to its diameter in the mature trees. There was no significant increase in the fiber diameter and fiber lumen diameter from the pith to the middle then there is a significant increase till the bark and there was a decrease from the pith to the middle then there is no significant increase to the bark of the young trees. We can conclude that the fiber length of the tow ages lies within the fiber lengths ranges used in pulp and paper manufacturing. The average of Runkel ratio of the mature trees also lies within the values required for pulp and paper manufacturing so it maybe more suitable than the young trees. Crystals in chambered fibers، libriform fibers and fibers with dentate end were observed.

Non-wood fibers are projected as fast-growing resources and sustainable alternate materials to reduce deforestation and enhance efficiency in the pulp and paper industry. This paper addressed the paucity of data on the fiber morphological characteristics (Fiber Length, Diameter, Lumen Diameter, and Wall Thickness) and pulping properties (Slenderness Ratio, Rigidity Coefficient, Flexibility Coefficient, Runkel Ratio, Solids Factor, and Luce’s Shape Factor) for Silk Cotton, leaves and stalk of Elephant Grass and Sugarcane Bagasse found in Ghana, especially, as environmental variations may cause differences in regional data. Observed values for the studied parameters were within the suitable range for paper production and differed from those reported for other regions. Elephant Grass (stalk) and Bagasse that had higher values of Fiber Length (4101.42 ± 197.89 and 3960.20 ± 194.35 µm), Diameter (60.03 ± 1.82 and 59.85 ± 1.72 µm), Lumen Diameter (33.33 ± 1.76 and 35.97 ± 1.38 µm), Wall Thickness (13.35 ± 0.83 and 11.94 ± 0.55 µm), Slenderness Ratio (70.8 ± 4.2 and 67.2 ± 3.4), and Flexibility Coefficient (55.7 ± 2.3 and 55.7 ± 2.3) would perform better during paper production. They would exhibit good physico-mechanical properties suitable for manufacturing flexible, high tearing, elastic, dense, smooth, and well-formed papers with high tensile and bursting strengths. Silk Cotton may also produce good papers with low tearing index, well-bonded, rigid, bulky, and coarse textured.

Eucalyptus camaldulensis (Ec) × E. urophylla (Eu) and reciprocal hybrid crosses were evaluated for growth and wood traits at four years at West Godavari Dt, Andhra Pradesh State located in Southern India, in relation to full and half sib progenies of pure E. camaldulensis maternal parents. Interspecific hybrid progenies had 16.6% higher average growth and 8% lower average wood basic density than pure species progeny. The interspecific hybrid progenies fibre properties viz., fibre length, fibre width, lumen diameter and fibre wall thickness were comparably higher than pure species progeny and check clones. The Ec × Eu crosses had comparable growth and wood basic density as the reciprocal hybrid progeny, but fibre length was 3.4% higher than the Eu × Ec hybrids, the values being statistically significant at p<.001 level. Analysis of variance of data was done using the 20th Edition of Genstat software (VSNi). Growth and fibre traits showed a positive relation but wood basic density showed a negative correlation (r = -0.94). There was a positive correspondence between the General Combining Ability (GCA) of pure E. camaldulensis maternal parents and their General Hybridizing Ability (GHA) for growth. The study showed that parents of Ec and Eu could be used to improve the growth and fibre traits in interspecific hybrids.

The fiber index including fiber length, width, wall thickness and lumen diameter of Ferrocalamus strictus culms (1, 2, and ≥ 3 years) from Jinping, Mojiang and Lvchun counties of Yunnan Province was determined and the elemental content of the soil was also determined to analyze the fiber characteristics. The average relative fiber index measured for F. strictus culms were fiber length (1.30 mm), width (21.57 μm), slenderness ratio (60.79 μm), wall thickness (4.21 μm), lumen diameter (7.22 μm), and runkel ratio (1.22 μm), which belonged to the range of middle and long fibers. The fiber length increased with the culm age. The proportion of long fiber increased while short fibers decreased along with culm maturing. The fiber morphology did not show a specific trend with the culm height. Fiber length reached the maximum in the bottom portions of the culms. There is a correlation between fiber morphology and soil elements, the content of organic matter, total potassium, total sulfur, total aluminum, total zinc, total iron, total boron, alkali-hydrolyzed nitrogen and available silicon in the soil affects fiber morphology. The content of organic matter, total boron and alkali-hydrolyzed nitrogen in the soil from Mojiang County was largest. Comparatively, the culm fiber in Mojiang County had the best fiber index performance for utilization, since the greatest proportion of medium and long fibers and the optimal distribution of fiber length frequency was obtained from the culms in Mojiang County. This study can provide a theoretical basis for large-scale bamboo forest cultivation and the development and utilization of bamboo culm fiber.

The present study emphasized on wood trait indices of Acrocarpus fraxinifolius for understanding the suitability of the species for paper and pulp industries. The study was conducted at the College of Forestry, Ponnampet, Karnataka in 2020. The wood core samples were collected from the trees falling under 130 to 150 cm girth class, standing in coffee-based agroforestry systems of Kodagu, Karnataka, India. A total of 12 wood core samples were collected using the Presseler’s increment borer at breast height level. For wood fibre analysis the core portion was divided and three, i.e., near to the pith portion, middle and periphery, and made as a composite sample. Core samples were macerated using Jeffreys solution technique at Forest Product and Utilization Laboratory, College of Forestry, UAHS, Shivamogga. Fifty measurements on fibre parameters (Fibre length, Fibre width, Fibre wall thickness, and Fibre Lumen width) were recorded for each sample under a stereomicroscope with an inbuilt Image Analyzer. The mean fibre properties recorded, were used for calculating wood anatomical indices such as the Runkel ratio, Slenderness ratio, Flexibility coefficient, and Rigidity coefficient using standard formulas. The mean Runkel ratio, Slenderness ratio, Flexibility coefficient, and Rigidity coefficient were 0.580, 60.132, 63.290, and 0.184 respectively. The anatomical screening suggests that the species can be used as raw material for paper production, based on the indices. Further research is required to explore the mechanical and chemical properties of commercial exploitation for pulping.

The utilization of branchwood as lignocellulosic raw material source for paper production may have the potential of solving the problem of the availability of raw material in the pulp and paper industry. This study therefore compared the chemical composition and fiber morphological indices (according to Franklin’s method) of stemwood and branchwood in Eucalyptus camaldulensis and Pinus halepensis trees grown in Egypt. The statistical analysis showed a significant effect of species, wood type (stem and branchwood), and their interaction on the measured chemical constituents and fiber morphological indices at 0.05 significance level. In both genera, the stemwood exhibited a higher percentage of cellulose and hemicellulose and was lower in lignin, total extractives, and ash than those measured in branchwood. Also in both genera, the stemwood was higher in fiber length, Runkel ratio, rigidity coefficient, Muhlsteph ratio, and Luce’s shape factor, and lower in basic density and flexibility coefficient than those in branchwood. Based on the chemical analysis and the fiber morphological indices, the stemwood and branchwood of both species were suitable for paper production with various qualities. Moreover, good correlations were found in both stem and branchwood between the basic density and the fiber wall thickness and fiber lumen diameter. ln contrast, there was an independent association between the stemwood basic density and the fiber length, and this relationship in branchwood was positive for both genera.

This study reports on radial variations of anatomical parameters of aerial roots Ficus bengalensis (Thandlu) such as fibre length, fibre diameter, fibre lumen diameter, fibre wall thickness, vessel element length, vessel diameter and vessel frequency. Certain important physical and mechanical properties of Thandlu wood such as equilibrium moisture content (EMC), specific gravity, density, flexural strength (modulus of rupture-MOR), flexural stiffness (modulus of elasticity-MOE), compressive strength parallel to grain (maximum compressive stress-MCS), compressive strength perpendicular to grain and surface hardness were also investigated. Average air-dry density of Thandlu wood was found to be 537.6 ± 91.4 kg/m 3 . Moreover, specific gravity exhibited increasing trend from pith to periphery and average values were found to be correlated with anatomical properties. Radial variations of anatomical parameters were observed to be significant. Fibre lumen diameter was negatively correlated while fibre wall thickness was positively correlated with density. Similarly, vessel element length was positively correlated with fibre length and fibre lumen diameter was found to be positively correlated with the fibre diameter. The physical and mechanical properties in air-dry condition of Thandlu wood were compared with Tectona grandis (Teak) wood. Naturally having long cylindrical shape, light to moderately heavy wood and moderate to strong mechanical parameters of Thandlu in dry condition, their traditional applications in different areas are well supported by the observations made in the present study.

This paper reports relationships between wood and fibre traits and investigates the potential for using genetic selection to improve traits that will increase both the yield and the value of the western hemlock (Tsuga heterophylla (Raf.) Sarg.) pulp wood resource. Strong family effects were present in the internal wood and fibre properties of relative wood density, average fibre length, and fibre coarseness. Heritability estimates for these traits ranged from 0.5 to 0.9. Heritability estimates for growth variables of height and diameter ranged from 0.15 to 0.2. Beside the moderate to high heritabilities for internal wood variables, coefficients of variation at the individual and family mean level ranged from 7.5to 13% and from 4 to 6.5%, respectively. Correlations at an individual phenotypic and genetic level showed adverse correlations between growth rate and both relative wood density (negative correlation) and fibre coarseness (positive correlation). A significant negative phenotypic correlation between relative wood density and coarseness would appear to be due to the fact that both traits were strongly correlated to growth rate. The partial correlation controlling for diameter between coarseness and diameter was nonsignificant. Power analysis demonstrated that pulp and fibre traits could beassessed effectively using as few as six individuals per family.

The purpose of this study is to evaluate the anatomical, physical, and mechanical properties of four pioneer species, i.e., batai (Paraserianthes moluccana), ludai (Sapium baccatum), mahang (Macaranga gigantea), and sesendok (Endospermum malaccense). Correlation of factors influencing density, shrinkage, and mechanical properties were also discussed. Samples were obtained from the Forest Research Institute Malaysia (FRIM) campus. From the result obtained, these four pioneer species characterised by medium-to-large vessel with absent of tyloses and gum deposit, fine ray, thin walled fibre, runkel ratio less than 1.0, low in density, and mechanical properties. Sesendok has significantly higher value in fibre length, fibre diameter, fibre lumen diameter, fibre wall thickness, vessel diameter, density, MOR, MOE, compression parallel to grain, and shear parallel to grain compared to the other three pioneer species which were 2001 µm, 45 µm, 35 µm, 5.1 µm, 300 µm, 514 kg/m3, 79.5 N/mm2, 9209 N/mm2, 38.7 N/mm2, and 10.1 N/mm2, respectively. Between these four pioneer species, ludai has significantly higher in runkel ratio which was 0.57, whereas mahang shows significantly higher in slenderness ratio and number of vessels/mm2 which were 50.2 and 5 vessel/mm2, respectively. On the other hand, batai has higher tangential, radial and longitudinal shrinkage compared to ludai, mahang, and sesendok which were 3.0%, 2.4%, and 0.8%, respectively. Based on the basic property study, batai, ludai, mahang, and sesendok could be suitable for pulp and paper, plywood, light construction, furniture, interior finishing, and general utility. Fibre length, fibre wall thickness, and vessel diameter correlated significantly with density and mechanical properties. Shrinkage and mechanical properties were significantly influenced by density.

The pulp and Paper industries are growing at a tremendous rate. To satisfy the raw material supply and sustainability of their future industries need an alternative resource from fast-growing tree species. Poplar is one of the world’s fastest-growing lightwood trees with its used in several industries. The present work relies on the comparative fiber morphological dimensions of four species of poplar i.e. Populus alba L, Populus ciliata Wall. ex Royle, Populus euphratica Oliv, and Populus nigra L. The quality of pulp and paper was directly related to the fiber dimensions i.e., fiber length, fiber lumen diameter, and fiber wall thickness. A number of wood properties related to paper quality were also derived from the fiber dimensions including the Runkel ratio, flexibility coefficient, solid factors, luce’s-shape factors, slenderness ratio and wall coverage ratio. The mean value of fiber length, fiber diameter, fiber wall thickness and basic density of these four species ranged from 919-1425 μm, 19.71-25.85 μm, 2.72-4.99 μm and 0.38-0.54 g cm⁻¹ respectively. The prominent objective was to compare the fiber quality of these four poplar species within among self and also with an exotic poplar species Populus deltoides and other fast-growing tree species.

Triploid breeding based on unilateral sexual polyploidization is an effective approach for genetic improvement of Populus, which can integrate heterosis and ploidy vigor in an elite variety. However, the phenotypic divergence of unselected allotriploids with the same cross-combination remains poorly understood, and the contributions of ploidy, gender, and genotype effects on phenotypic variation are still unclear. In this study, wood and fiber traits, including basic density (BD), lignin content (LC), fiber length (FL), fiber width (FW), and fiber length/width (FL/W), were measured based on a 10-year-old clonal trial, including full-sib diploid and triploid hybrids of (Populus pseudo-simonii × P. nigra ‘Zheyin3#’) × P. × beijingensis, and contributions of ploidy, gender, and genotype effects on the variation of these traits, were disaggregated to enhance our understanding of triploid breeding. We found a significant phenotypic variation for all measured traits among genotypes. All the wood and fiber traits studied here underwent strong clonal responses with high repeatabilities (0.55–0.76). The Pearson’s correlation analyses based on the best linear unbiased predictors (BLUPs) revealed that BD was significantly positively correlated with FL (r = 0.65, p = 0.030), suggesting that BD could be improved together with FL during triploid breeding. The FL of the triploids was significantly larger than that of the diploids (p < 0.001), suggesting that ploidy strongly affected the variation of FL traits. The difference between females and males was not significant for any measured trait, implying that gender might not be a major factor for variation in these traits. Further analyses of variance components showed that genotype dominantly contributed to the variation of BD, LC, and FW traits (with 54, 62, and 53% contributions, respectively) and ploidy contributed strongly to variation in FL and FL/W (77 and 50%, respectively). The genetic coefficient of variation (CVG) of triploids for each trait was low, suggesting that it is necessary to produce many triploids for selection or to use different Populus species as parents. Our findings provide new insights into the genetic effects of ploidy, gender, and genotype on wood and fiber traits within a full-sib poplar family, enhancing the understanding of the triploid breeding program of Populus.