Submitted to: Plant Cell Tissue and Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2011
Publication Date: 9/19/2011
Citation: Bell, R.L., Scorza, R., Lomberk, D.F. 2011. Adventitious shoot regeneration of pear (Pyrus communis L.) cultivars. Plant Cell Tissue And Organ Culture. 108(2):229-236. Interpretive Summary: The ability to induce new shoot formation from single plant cells or groups of plant cells is needed in order to produce whole plants following genetic engineering procedures commonly employed for the improvement of fruit crops and to determine the function of specific plant genes. Inducing new shoot formation in pears is generally difficult, and the major varieties, 'Bartlett', 'Bosc', and 'Anjou', generally exhibit only moderate levels of new shoot formation, and the production of new "engineered" plants is inefficient, requiring large numbers of original leaves. Leaf tissue of twenty-four pear varieties were placed on a commonly utilized artificial plant growth medium in order to compare their abilities to form new shoots and to select the best variety. 'Conference' pear was found to form new shoots with 88% efficiency, confirming previous studies, and 'Magness' and 'Dr. Jules Guyot' also formed new shoots at about 70% efficiency. The use of 'Conference' as an efficient "model" variety is recommended and will allow smaller, more efficient, and less costly experiments for studying gene function.
Technical Abstract: Adventitious shoot regeneration of twenty-four pear clones was compared in a common in vitro shoot induction and development protocol. This study also compared cultures newly established from scionwood with cultures that have been in long-term cold storage. In vitro cultures of 13 Pyrus clones and budwood from 23 Pyrus clones were obtained from the National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon. With the exception of two clones, the genotypes were P. communis L. cultivars. The basal shoot induction media consisted of Chevreau and Leblay (CL) basal nutrients, vitamins, and organics (Chevreau and Leblay, 1993). The analysis of variance indicated that differences among cultivars were highly significant, and the main effect of culture origin was non-significant. However, there was a significant interaction between cultivar and culture origin with a percentage regeneration of 'Abate Fetel' from new budwood, significantly greater than that from long-term in vitro cultures, while 'Jesinji Vodenac' cultures derived from the old NCGR cultures regenerated significantly more adventitious shoots. The ranges of mean regeneration frequency were similar for both in vitro (0 to 87.7%) and scionwood-derived cultures (0 to 70.7%). Maximum regeneration was observed for 'Conference', followed by 'Magness', 'Dr. Jules Guyot' and 'Packham's Triumph'. The range of the number of adventitious shoots was relatively narrow with the minimum of 1.0 for seven cultivars to 2.2 for 'Conference'.