Étude ampélométrique de feuilles adultes de somaclones du cv. Grenache N (Vitis vinifera L.)

Abstract

To obtain a broader variability of the Grenache N grapevine, somaclones were produced from anther calli and placed in two different environments: a poor sandy soil (Espiguette) and a richer silty clay soil (Chapitre). To evaluate the observed variations at the foliage level, an ampelometric study was conducted over three consecutive years. Various biometrical analyses revealed that (i) leaf size varies in relationship with the environment: in the poor soil, leaves are smaller than in the rich soil for the control clone as well as the somaclones; (ii) whatever the environment, indentation is deeper in somaclone leaves than in control leaves, even 10 years after outplanting; (iii) some somaclones with deeply or barely indented leaves have a more stable behaviour, while others have a leaf morphology changing with the year and the environment; (iv) leaf indentation parameters defined by the authors allow for a fairly good characterization among somaclones and control: indentation index X5, (S1 + S2)/(L + L1), appears to have the highest discrimination potential; vein length and angle parameters do not allow for discrimination. Representation of the somaclones based on a "theoretical leaf", obtained from the different measurements, gives interesting supplementary information for the interpretation of the results. Principal component analysis leads to more information on the parameters as well as on individuals. This method was therefore retained for further analyses. In conclusion, this study shows that before commercial introduction of a somaclone, one must ensure that the morphology always corresponds to the grapevine type. Key words: in vitro, somatic embryos, variability, morphology, indenting, principal component analysis, discriminant analysis. [Journal translation]