A microculture approach towards enhanced productivity and genetic improvement of pecan (Carya illinoensis)
Mature pecan nuts provide a more convenient, practical, and readily available explant source, and extend the sampling period for in vitro research on this species to a year-round basis. Axenic cultures from mature pecan embryos were established in vitro by reducing the water availability in the initial explanting media. This enabled study of the regenerative capacity of the mature pecan embryo explants, and the factors affecting shoot multiplication and rooting. A simple procedure was adapted for the measurement and comparison of water availability in the explanting media. Disinfestation of up to 65% of the cultures was accomplished, depending on the medium formulation, compared to 100% loss to contamination on control medium. Prolific production of axillary and adventitious shoots from the embryonic axis was induced by adding 5 $\mu$M IBA and 20 $\mu$M BAP to the culture media. The retention of cotyledons was essential for shoot initiation and long-term shoot development. TDZ at 25 $\mu$M produced somatic embryos and adventitious buds. Sixty-one percent of the excised cultured cotyledon segments formed adventitious roots at 50 $\mu$M NAA. Axillary buds on microcuttings were induced to grow only when media were supplemented with gibberellic acid. Microcuttings cultured on auxin-free media after preculture on media with 20 $\mu$M IBA in the dark for one week gave the best rooting results (30%). A new micrografting technique was developed as an alternative clonal propagation method. A unique apparatus was designed to splice the in vitro-derived scion and rootstock together during the micrografting process.
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign