Y. H. Weng, J. Kershaw, K. Tosh, G. Adams and M. S. Fullarton
ADAMS, G. W. and E. K. MORGENSTERN (1991): Multiple-trait selection in jack pine. Canadian Journal of Forest Research 21: 439-445.
BUFORD, M. A. (1986): Height-diameter relationships at age 15 in loblolly pine seed sources. Forest Science 32: 812-818.
BUFORD, M. A. and H. E. BURKHART (1987): Geneticimprovement effects on growth and yield of loblolly pine plantations. Forest Science 33: 707-724.
CARSON, S. D., O. GARCIA and J. D. HAYES (1999): Realized gain and prediction of yield with
The Christmas rose is becoming a very important ornamental plant on the market. It is relatively new to intensive production technologies. The number of genetically-improved varieties on the market is limited, and many of the old cultivars are no longer available because of slow and economically unfeasible vegetative propagation. In the future, its genetic improvement will probably become inevitable. New cultivars will have to satisfy the specific requirements of the market and producers as well as strict environmental policy. In order to obtain new cultivars it will be necessary to evaluate the existing germplasm and apply an adequate genetic breeding approach. There are seven main possibilities of creating new varieties: the use of natural variation associated with seed germination, population approach based on recurrent selection, individual selection based on specific genetic combinations, the creation of inbred lines and the formation of hybrids, interspecific hybridisation, mutagenesis and genetic engineering. Molecular markers can be very helpful during the breeding process. They can be used in order to study genetic relationships amongst populations, ecotypes, varieties, and hybrids.
H. S. Ginwal, Pradip Kumar, V. K. Sharma, A. K. Mandal and C. E. Harwood
MATHESON, A. C. and MULLIN, L. J. (1987): Variation among neighbouring and distant provenances of Eucalyptus grandis and E. tereticornis in Zimbabwean field trials. Australian Forest Research 17: 233-250.
OTEGBEYE, G. O. (1985): Productivity in Eucalyptus camaldulensis Dehnh. and its conservation to geneticimprovement in the savanna region of Nigeria. Silvae Genetica 34: 121-126.
PINOPUSARERK, K., DORAN, J. C., WILLIAMS, E. R. and WASUAWANICH, P. (1996): Variation in growth of Eucalyptus camaldulensis provenances
P.G. Suraj, K. Nagabhushana, R. Kamalakannan and M. Varghese
Hardner C, Dieters M, DeLacy I, Neal J, Fletcher S, Dale G, Basford K (2011) Identifying deployment zones for Eucalyptus camaldulensis × E. globulus and × E. grandis hybrids using factor analytic modelling of genotype by environment interaction. Aust Forestry 74(1):30-35. https://doi.org/10.1080/00049158.2011.10676343
Harwood CE, Nikles DG, Pomroy PC, Robson KW (1997) Geneticimprovement of E. pellita in North Queensland, Australia. In: Proceedings of the IUFRO Conference on Silviculture and improvement of eucalypt, Salvador, pp 219–226.
Eleven Populus × generosa populations were developed in the Pacific Northwest by annual controlled hybridization of P. deltoides and P. trichocarpa between 1991 and 2001. Mass selection for Melampsora leaf rust resistance was observed in the field as a threshold character in identifying seedling phenotypes for clonally replicated evaluation. The effectiveness of the approach was assessed for each annual population by comparing the distribution of phenotypes in unselected seedling populations with the distribution of selected genotypes in the clonal field tests established in successive years and evaluated at the approximate same level of disease severity using two selection thresholds corresponding to chlorotic and healthy tissue. Bi-directional selection was used as an initial check on the efficacy of the procedure and resulted in a wide separation in liability between the positive (0.06 threshold units (T.U.)) and negative (−2.45 T.U.) selection groups when tested as clones. The other 10 seedling populations that were subjected solely to directional selection exhibited a mean increase in incidence above the first selection threshold at the clonal stage (47 versus 81%) that was accompanied by an improvement in population liability (−0.06 versus 0.50 T.U.) and a reduction in population standard deviation (0.83 versus 0.54 T.U.). The change in liability was strongly related by polynomial regression to selection intensity and a grouping of populations based on infection-season precipitation (r2=0.98). The mean liability of four of the 10 seedling populations observed during years of high infection-season rainfall was six-fold lower than the mean liability of those populations observed during the other six years of lower infection-season rainfall (−0.12 T.U. versus −0.02 T.U., respectively), indicating that populations undergoing evaluation during years of heavy precipitation experienced more intense rust exposure. Moreover, quadratic functions showed that populations undergoing rust evaluation during years of high rainfall were more responsive to increases in selection intensity above the vertex of the function (i.e. 13.20 versus 3.43 T.U.). Realized heritability averaged 0.63 for all ten populations subjected solely to directional selection.
Results of a seed source evaluation trial of Jatropha curcas Linn. laid out in 1996 at Jabalpur (M.P), a semi arid region of India are reported and discussed. Seeds collected from ten sources from central India representing the states Madhya Pradesh and Maharashtra viz. Gondia, Bichia, Balaghat, Niwas, Khandwa, Burhanpur, Nasik, Chindwara, Kundam and Jabalpur were evaluated for their growth performance from nursery stage (3 months) to field (two years). Variation in seed oil content of different sources were also studied and reported. Significant differences between the seed sources at age 27 months were observed for height, collar diameter, number of branches leaf area and field survival. Seeds collected from different sources also varied significantly in respect of seed and kernel weight and oil content in seed/kernel. The Chhindwara (M.P.) source performed the best and yielded a maximum oil of 39.12% from whole seed and 58.12% from kernel. The oil content ranged from 33.02 to 39.12% in whole seeds and 47.08 to 58.12% in kernel, across the seed sources. The performance of Kundam (M.P.), Jabalpur (M.P.), Bichia (M.P.), Niwas (M.P.) and Nasik (Maharashtra) sources were also found satisfactory for oil yield. Results indicate that genetic differences exist between the seed sources of J. curcas. The growth traits showed significant positive correlation with each other. Fair differences between phenotypic and genotypic coefficient of variability were observed. Heritability (broad sense) values were fairly good with regard to leaf area, height and collar diameter in comparison to survival percent. The relative performance of these sources was fairly consistent throughout the observation period.
H. S. Ginwal, Pradip Kumar, V. K. Sharma and A. K. Mandal
Results of a provenance trial of Eucalyptus camaldulensis Dehnh. laid out in 2001 at Seothi (30° N Lat., 76° E Long. and 250 m altitude) Haryana, a semi-arid region of India are reported and discussed. Six seed sources from Australia viz. Laura River, Emu Creek, Degrey River, Wiluna, Kennedy River, Morehead River were evaluated from nursery stage (3 months) to field performance (2 year). Two sources viz. E.tereticornis (Helenvele, Qld) and FRI-4 a local seed source were used as control (check material). Significant differences between the seed sources at nursery stage were observed for collar diameter (P < 0.05) and number of leaves (P < 0.01). At age 2 years, significant differences between the seed sources (P < 0.05) were observed for height and field survival. The two seed sources viz. Emu Creek Petford, QLD and Laura river, QLD ranked first and second for height and survival at this age. Results indicate that genetic differences exist between the sources of E. camaldulensis. None of the traits assessed (viz. height, collar diameter, number of leaves, number of branches and survival) was found to correlate with any of the geographical coordinates of the site (latitude, longitude and altitude). There were fair differences between phenotypic and genotypic coefficient of variability. Heritability values were fairly high for height and clear bole length in comparison to collar diameter, number of branches and survival. The relative performance of these provenances was fairly consistent throughout the period of observation. The two sources viz. Laura river, QLD and Emu Creek Petford, QLD are recommended for potential source for plantation programme under semi-arid conditions.
Results of a provenance trial of Acacia nilotica Willd. ex Del. laid out in 1993 at Tropical Forest Research Institute Campus, Jabalpur (23°N lat., 79°E long. and 400 m altitude) Madhya Pradesh, a semi-arid region of India are reported and discussed. Nineteen provenances from India, Pakistan, Sudan, Senegal and Yemen were evaluated in the field at age three and six years. Local source of A. nilotica (S.F.R.I., Jabalpur) was used as check material for comparison. Significant differences between the provenances (P < 0.05) were observed for height, diameter at breast height (DBH), number of branches and field survival. The provenances from Gujrat (Punjab), Pakistan, ranked first for growth traits namely height, DBH and survival. The next superior provenance was from Beihan, Yemen, which scored second highest values of height and DBH and had good survival at age six years. Results indicate that genetic differences exist between the provenances of A.nilotica. None of the traits assessed (viz. height, DBH, number of branches, inter-nodal length and survival) were found to correlate with any of the geographical coordinates of the provenances (latitude, longitude and altitude). Height, DBH and number of branches showed significant and positive correlation with each other. Fair differences between phenotypic and genotypic coefficient of variability were observed. Heritability values were found fairly good for height, DBH and number of branches as compared to inter-nodal length. The relative performance of these provenances was fairly consistent throughout the period of observation at three and six year. The two sources viz. Gujrat (Punjab), Pakistan and Beihan, Yemen, are recommended for plantation programme under semi-arid conditions.
Twelve trees in a 36 year old full-sib progeny plantation, testing a part of the Scots pine breeding population, were analysed for wood density and the width of the earlywood and latewood sections in each annual ring. Wood samples (stem discs) were taken with 1 m intervals along the stem and the analyses covered thus the whole stem. Based on these data, the biomass of the earlywood and latewood of each annual ring in each 1 meter stem section was estimated. Latewood density increased from pith to bark while it decreased from stem base to top. Earlywood density was of similar size both radially and vertically. The biomass in each annual ring increased until around ring number 10 from pith for both wood types. For earlywood it then decreased while it remained quite constant for latewood. Latewood biomass decreased more rapidly towards the top of the tree than earlywood biomass. Heritabilities for earlywood and latewood in each annual ring at breast height (estimated in the same material in a previous study) were related to the corresponding biomasses to indirectly estimate overall heritability for wood density valid for the whole stem. The analyses indicate that the decrease in heritability for latewood density and increase for earlywood density, from the pith to bark, is compensated by the increase in latewood biomass in relation to earlywood biomass. Thus, the heritability of the latewood density and earlywood density seems to have the same influence on the overall heritability for density in the whole stem.
The two main objectives of this study were: (1) to determine how early is it possible to undertake selection to improve the stiffness of corewood; (2) to determine if the selection based on corewood stiffness could also improve outerwood stiffness, and vice versa. Breastheight data from two progeny trials of Pinus radiata D. Don were used. In the first trial (age 30 years), data on Silviscan predicted stiffness (MoE) was obtained for each growth ring on each core sample from 50 open-pollinated families. In the second trial (age 14 years), data on static-bending MoE was obtained using clearwood sticks (300 × 20 × 20 mm) cut from each tree from 18 control-pollinated families. MoE varied from 3.5 GPa in rings 1-5 to about 17 GPa in rings 21-25. Coefficients of variation of corewood and outerwood MoE were about 20-30% and 15-20% respectively. Estimates of narrowsense heritability for MoE were generally higher (0.50-0.70) in the corewood compared with the outerwood (0.15-0.30). Early selection for MoE could yield substantial gain in corewood MoE but only small gains, if any, in outerwood MoE (especially for rings 21-30). Estimated genetic correlations between density and stiffness appeared moderate in the corewood zone, but high in the outerwood zone. Selection based on density (using 5-mm cores) and acoustic stiffness (using standing tree tools), assessed at age 6-7 years, appeared to be a good option to improve both corewood and outerwood stiffness.