the growth rate of W1 was faster only in the early growth period. The course of growth was significantly affected both by physiological and morphological modifications. Furthermore, morphological components were found to be mostly influenced by the specific leaf area (SLA, i.e. the total leaf area per unit leaf mass). Specifically, until 1200GDDSLAwas 20% (year 1999) and 16% (2000) higher in W1 than in W0