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. RODRIGUEZ and M. TORO (1998): An application of Bayesian techniques to the genetic evaluation of growth traits in Eucalyptus globulus. Can. J. For. Res. 28: 1286-1294. VAN TASSELL, C. P., G. CASELLA and E. J. POLLAK (1995): Effects of Selection on Estimates of Variance Components Using Gibbs Sampling and Restricted Maximum Likelihood. J. Dairy Sci. 78: 678-692. VAN VLECK, L. D. and J. P. CASSADY (2005): Unexpected estimates of variance components with a true model containing genetic competition effects. J. Anim. Sci. 83: 68-74. WILLHAM, R. L. (1963): The covariance

. Annals of Botany 53 : 349–362. C onnolly , T., I. D. C urrie , J. E. B radshaw and J.W. M c N icol (1993): Inter-plot competition in yield trials of potatoes ( Solantum tuberosum L.) with single-drill plots. Ann. Appl. Biol. 123 : 367–377. C orrell , R. L. and R. B. A nderson (1983): Removal of intervarietal competition effects in forestry variety trials. Silvae Genetica 32 (5–6): 162–165. D e B ell , D. S. and C. A. H arrington (1997): Productivity of Populus in monoclonal and polyclonal blocks at three spacings. Can. J. For. Res. 27 : 978–985. de R esende


Variance components of tree height (HT) and stem diameter at 1.3 m above the ground (DBH) were investigated for the eight open-pollinated families of Zelkova serrata (Thumb.) Makino planted with three different initial planting spacings in a progeny test site, Chiba, Japan. Parent–offspring correlations were also evaluated by using these families and their mother trees. The smallest values of HT and DBH were observed in the narrowest initial planting spacing (1.10 x 1.10 m) compared to those in medium (1.30 x 1.36 m) and wide (2.00 x 1.80 m) spacings, suggesting that adverse effects of competition with neighboring trees occurred on both height and radial growth. Similar to HT and DBH, the initial planting spacings also affected the genetic parameter estimates: the ratio of family variance component to total phenotypic variance showed the highest value in narrow initial planting spacing for both HT and DBH. Thus, family variance component might include competition effects, leading to biased genetic parameter estimates. In contrast, parent–offspring correlation coefficients showed the highest value in wide initial planting spacing where competition effect might be smaller. Therefore, the growth traits of Z. serrata might be inherited from the parent to the offspring when competition effect was small.


Four hundred and sixty individual families of Pinus radiata, representing all provenances and populations in a 1978 seed collection, plus a local seed orchard control, were planted together in 1980 in a large trial in southern New South Wales, Australia. Provenance means and genetic parameters for growth measured at ages 3, 8 and 26 years plus stem straightness, branch angle and nodality at age 26 years are reported. Large provenance differences were apparent for all traits. The two island provenances, Cedros and Guadalupe, were significantly inferior to the mainland provenances and, due to competition effects, very few trees survived to age 26. Within the mainland provenances, the performance of Año Nuevo and Monterey was almost identical, with Cambria being less vigorous. The best performing seedlot for all traits was the local control. Differences between populations within the mainland provenances were apparent for diameter at age 26 within Año Nuevo and Cambria but not Monterey. Año Nuevo also showed population differences for stem straightness. Heritabilities for early growth were similar within Año Nuevo and Monterey but by age 26, the heritability for diameter was higher in Monterey. Within Cambria, heritabilities for growth and tree form at age 26 were close to zero. Genetic correlations between traits showed similar patterns for each of the mainland provenances, with the exception of correlations with stem straightness within Año Nuevo. Results are discussed in light of recent molecular studies of genetic architecture, levels of inbreeding in the native stands and possible effects of this inbreeding.

–599. Li, T., & Zheng, X. (2009). Entry and competition effects in first-price auctions: theory and evidence from procurement auctions. The Review of Economic Studies , 76(4), 1397–1429. Marshall, R. C. & Marx, L. M. (2007). Bidder collusion. Journal of Economic Theory , 133(1), 374–402. Vellez, M. (2011). Auctions versus negotiations: Evidence from public procurement in the Italian healthcare sector. CEIS Tor Vergata , 9(4), 191.

References Beckage B., Clark J.S. 2003. Seedling survival and growth of three forest tree species: the role of spatial heterogeneity. Ecology, 84 (7), 1849-1861. Beyer F., Hertel D., Jung K., Fender A.C., Leuschner Ch. 2013. Competition effects on fine root survival of Fagus sylvatica and Fraxinus excelsior. Forest Ecology and Management, 302, 14-22. Breda N., Granier A., Barataud F., Moyne C. 1995. Soil water dynamics in an oak stand. I. Soil moisture, water potentials and water uptake by roots. Plant and Soil, 172, 17-27. Brzeziecki B. 2000. Life

): Using portfolio theory to guide reforestation and restoration under climate change scenarios. Climate Change 89: 355-370. EULER, F. VON, P. BARADAT and B. LEMOINE (1992): Effects of plantation density and spacing on competitive interactions among half-sib families of maritime pine. Canadian Journal of Forest Research 22: 482-489. FOSTERA, G. S., R. J. ROUSSEAUB and W. L. NANCEC (1998): Eastern cottonwood clonal mixing study: intergenotypic competition effects. Forest Ecology and Management 112: 9-22. FOWLER, D. P. (1986): Strategies for the genetic improvement of

References Ackefors H., Lindqvist O.V. 1994 - Cultivation of freshwater crayfishes in Europe - In: Freshwater crayfish aquaculture in North America, Europe, and Australia: Families Astacidae, Cambaridae and Parastacidae (Ed.) J.V. Huner, Food Products Press, NY, London, Norwood: 157-216. Axelsson E., Nystrom P., Sidenmark J., Bronmark Ch. 1997 - Crayfish predation on amphibian eggs and larvae - Amphibia-Reptilia 18: 217-228. Barnett H.K., Richardson J.S. 2002 - Predation risk and competition effects on the life-history characteristics of larval Oregon spotted

): Bias in genetic variance estimates due to spatial autocorrelation. Theor. Appl. Genet. 86: 349-355. MAGNUSSEN , S. (1994): A method to adjust simultaneously for statial microsite and competition effects. Can. J. For. Res. 24: 985-995. POJAR, J. and A. MACKINNON (1994): Plants of the Pacific Northwest Coast, Washington, Oregon, British Columbia & Alaska. Lone Pine Publishing, Vancouver, British Columbia. POLLARD, D. F. W. and F. T. PORTLOCK (1986): Intraspecific variation in stem growth of western hemlock. Can. J. For. Res. 16: 149-151. R DEVELOPMENT CORE TEAM (2011

: 10.1111/j.1365-3180.2011.00873.x. SAINI, H.S. – SEDGLEY, M. – SPINALL, D.A. 1984. Development anatomy in wheat of male sterility by induced by heat stress. Water deficit or abscisic acid. In Australian Journal of Plant Physiology , vol. 11 , pp. 243–254. DOI:10.1071/PP9840243. SHABAN, S.A. – SOLIMAN, S. – YEHIA, Z.R. – EL ATTAR, M.H. 2009. Weed competition effects on some Triticum aestivum quality and quantity components. In Egyptian Journal of Agron omy, vol. 31 , pp. 135–147. SHEHAZD, M.A. – NADEEM, M.A. – IQBAL, M. 2012. Weed control and yield attributes