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Conference paper, 2003

Variation in fertility and its impact on gene diversity in a seedling seed orchard of Eucalyptus tereticornis

Varghese, M; Namasivayam, Ravi; Son, SeogGu; Lindgren, D

Abstract

Impact of fertility variation in a progeny trial of Eucalyptus tereticornis in south India was studied at four years of age with the intention to convert it to a seedling seed orchard. A hypothetical phenotypic selection of 200 trees for tree height resulted in only 18% fertile trees. There was tremendous variation in fertility (sibling coefficient, A=17.4). This would cause excessive representation of the 12 most fertile trees resulting in high genetic drift, inbreeding and low status number (Ns=8.5). Collection of equal quantities of seed per tree would reduce sibling coefficient and almost double the status number in seed crop. Much of the diversity loss occurs in the first generation as indicated by 65% decline in relative status number in the first generation compared to six advanced generations. Retaining 35 additional pollen parents would increase status number and variance effective population size by 100% in the first generation, but reduce gain by 2% compared to the trees selected for genetic merit. Both strategies would reduce inbreeding coefficient in the second generation. Combination of the two - retaining trees for pollination only and limiting the number of seeds harvested from individual trees would reduce impact of fertility variation in seedling seed orchards and be useful as management strategies in domesticating tropical eucalypts

Published in

Title: Eucalyptus plantations: research, management and development. Proceedings of the international symposium, Guangzhou, China, 1-6 September 2002
ISBN: 981-238-557-6
Publisher: World Scientific Publishing Co. Pte. Ltd

Conference

Eucalyptus plantations: research, management and development. Proceedings of the international symposium, Guangzhou, China, 1-6 September 2002