Studies were conducted in four regions of central Greece (Larisa, Karditsa, Livadia, Thiva), to evaluate the productivity and fibre properties (fibre strength and fibre length) of the five most commonly grown cotton cultivars in these regions. The experiments lasted for 6 years (1995)(1996)(1997)(1998)(1999)(2000). All the characteristics tested were strongly influenced by the factors ÔyearÕ, ÔcultivarÕ and ÔregionÕ. Significant cultivar · region, year · cultivar, region · year and cultivar · region · year interactions occurred for all the characteristics studied. The cultivar Alegria had the highest seed-cotton and lint yield, while Aria had the lowest ones. Both cultivars gave the highest mean lint percentage but the lowest mean boll weight (MBW). Alegria had the lowest fibre strength, while Aria had the highest. The Acala-type cultivars, Acala SJ2 and Zeta 2, had intermediate seedcotton and lint yield, while Vered 171 had high seed-cotton and satisfactory lint yield. The three cultivars mentioned above had the highest MBW and very good fibre strength. Positive correlation was observed between fibre strength and length. In spite of the fact that mean fibre length was statistically the same in all cultivars, it was influenced by the factor ÔyearÕ, as a result of different weather conditions. The year 1996 was the most unfavourable one for seedcotton yield and MBW, because it was characterized by lower than average air temperatures and rather dry conditions for all study sites. The factor ÔregionÕ, a combination of different climatic conditions and cultural practices, influenced significantly all the parameters studied.

In this work, a combined HPLC-ELISA technique was used to associate in vitro rooting capacity of tree peony microcuttings with contents of cytokinin and auxin ; the cytokinin mainly detected corresponded to the N 6 -benzyladenine which had been added to the multiplication medium . Rooting capacity of explants was favoured by a preliminary accumulation of endogenous IAA only when levels of the BA absorbed from the multiplication medium had decreased . Main shoots coming from a 5-weeks subculture fulfilled these hormonal conditions and were the best microcuttings for rooting (87% rooting) . Main shoots coming from shorter cycles or axillary shoots coming from a 5-weeks cycle always contained high benzyladenine levels and had a low rooting capacity (25-55% rooting) . Root induction was associated with an early peak of indole-3-acetic acid followed by a 10-fold lower peak of endogenous ribofuranosyl-isopentenyladenine . Only a low and transitory accumulation of isopentenyladenine occurred during root development, and this could explain the lack of shoot development . Root development was efficient, especially in a medium containing activated charcoal, which led to an almost 3-fold decrease of IAA contents in roots .Abbreviations : AC = activated charcoal ; BA = N6 -benzyladenine ; ELISA = enzyme linked immunosorbent assay ; HPLC = high performance liquid chromatography ; IAA = indole-3-acetic acid ; IBA = indole-3-butyric acid ; iP = N6 -(62-isopentenyl)adenine; RDM = root development medium ; RIM = root induction medium ; 9RIP = 9-,0-d-ribofuranosyl-iP ; 9RZ = 9-a-d ribofuranosyl-zeatin ; Z = zeatin .

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N(6)-benzyl-adenine (BA) enhanced phyllogenesis and axillary bud development of Paeonia suffruticosa during in vitro culture allowing good propagation while N(6)-(Δ(2)isopentenyl)adenine (iP) did not. During the first five days of culture, the mitotic activity of BA-treated explants was higher than in the iP-treated ones. High BA levels were detected in the BA-treated explants, and this was correlated with the absence of or the low indole-3-acetic acid (IAA) content. The low iP levels measured in iP-treated explants were correlated with high endogenous IAA content; the new cytokinin / auxin ratio could explain the lack of axillary buds and the development of only one leaf. Abscisic acid (ABA) was detected neither in the controls nor in the cytokinin-treated explants during the first week. However, intensive restoration of ABA accumulation was observed in controls from the third week onwards. Both BA and iP-treated explants accumulated less ABA than the controls but this hormone appeared later in the BA-treated explants than in the iP-treated ones.

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