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Texas A&M University (2010)

Vegetative Propagation and Topophytic Responses of Selected Baldcypress Clones

King, Andrew R.

Titre : Vegetative Propagation and Topophytic Responses of Selected Baldcypress Clones

Auteur : King, Andrew R.

Université de soutenance : Texas A&M University

Grade : Master of Science (MS) 2010

Résumé
Baldcypress, Taxodium distichum (L.) Rich., var. distichum is a highly adaptable tree of significant ecological importance in the Southeastern U.S. Including Taxodium distichum var. imbricarium (Pondcypress) and Taxodium distichum var. mexicanum (Montezuma cypress), the native range is extended into south Texas and Mexico. Previously, baldcypress selections were made for drought, foliar salt exposure and high pH soil tolerance. Experiments were conducted beginning in May, 2008 to determine commercial viability of vegetative propagation by shoot tip cuttings of these selections, to identify treatment combinations that led to optimal rooted cutting quantity and quality, and to determine whether baldcypress cuttings displayed a topophytic effect and if so, if there was a correlation between branch angle on the ortet and topophysis exhibited by ramets during nursery production. The propagation studies revealed that rooted cutting quantity and quality were optimal when softwood cuttings were taken from south Texas and/or Mexican provenances and treated with either 7,500 or 15,000 mg·L-1 K-IBA (potassium salts of indole-3-butyric acid). A gradient was observed with cuttings from more southern and western provenances typically exhibiting greater rooted cutting quantity and quality than cuttings from more eastern and northern provenances. A tradeoff between greater rooting percentages in a substrate with greater aeration (100 percent perlite) versus greater root quality (root numbers, length, or mass) in a substrate with a higher water-holding capacity (100 percent peat moss) was also displayed. Additional basal wounding proved to be detrimental to both rooted cutting quantity and quality. A significant (P

Mots Clés : ramet — ortet — topophysis

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Page publiée le 10 novembre 2012, mise à jour le 22 février 2019