ISHS Acta Horticulturae 470: II International Symposium on Pistachios and Almonds
MULTIVARIATE ANALYSIS OF THE EFFECTS OF GROWTH REGULATORS ON THE REGENERATION OF PISTACHIO (PISTACIA VERA L.) CV. MATEUR FROM COTYLEDONS |
| Authors: | A. Chatibi, M.L. Kchouk, S. Thaminy, A. Ghorbel, T. Khsib |
| Keywords: | BAP, IBA, NAA, adventitious shoots, callogenesis, rhizogenesis |
| Abstract:
One of the main constraints encountered in Pistachio (Pistacia vera L.) micropropagation is the inability to produce a large number of rooted plantlets. This has been achieved recently through in vitro culture of cotyledons (Chatibi et al., 1996a) after investigation of three growth regulators BAP, IBA and NAA. On cotyledons, the trihormonal combination can induce a large range of tissue manifestations: (i) regeneration of adventitious shoots, (ii) rhizogenesis and (iii) callogenesis, together with various mixed effects. The cotyledon response was not always uniform within each class of media and multivariate computation was used to analyse the overall data. Discriminant Analysis (DA) permitted screening of seventeen uniform hormonal combinations to illustrate the main observations. However, apart from eliminating several ineffective media from the analysis, the DA also excluded interesting combinations. On the contrary, the Principal Component Analysis (PCA) gave a better description of the various media and their effects on organogenesis. PCA diagrammes permitted selection of at least nine interesting balanced media that promote pistachio micropropagation without the undesirable traits of rhizogenesis and callogenesis. It is difficult to define a theoretical model for the observed effects of the growth regulators since their effects are more related to the trihormonal balance in the medium than to a specific growth regulator. BAP was determinant in adventitious regeneration of shoots and proved to have well defined effects as concentrations increased to 2.0 mg.1-1, whereas NAA and IBA played the role of moderators. | |
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