PRODUCTIVITY STIMULATION IN STRAWBERRY BY APPLICATION OF PLANT BIOREGULATORS

Abstract

Influence of several plant bioregulators (PBRs) on yield and growth of strawberry plants in two field experiments was evaluated. Experiments were carried out at the Research Institute of Pomology and Floriculture, Skierniewice, Poland, in the years 1997-2000. In the first experiment conducted from 1997 to 1999 three cultivars (‘Senga Sengana’, ‘Dukat’ and ‘Elkat’) were sprayed 3 times during the blooming time with new formulations of preparations containing 2-naphthoxyacetic acid (BNOA) and/or gibberellic acid (GA3). It was found that the tested cultivars responded differently to the applied PBRs. ‘Senga Sengana’ responded positively, while ‘Dukat’ and ‘Elkat’ did not. Among evaluated bioregulators the best results were obtained after the application of Betoxon Super 050 SL (salt of 2-naphthoxyacetic acid with triethanolamine). It resulted in increased yield (by 31.9%) and improved fruit quality. Fruits from treated plants were larger (by 11.6%) and firmer than those from the control ones. Application of the PBRs had no influence on the degree of fruit infection with grey mould. The second experiment was carried out in 2000. Its aim was to stimulate the vegetative growth (determined by formation of runners and daughter plants) of three strawberry cultivars which are poor in forming runners and therefore difficult to propagate (‘Selva’, ‘Mara des Bois’ and ‘Vikat’) by application (three times in mid summer) of several PBRs. The following PBRs were applied: Pomonit Super 05 SL (5% triethanolamine salt NAA), Paturyl 100 SL (10% BA), Gibrescol 10 MG (10% GA3), Promalin 3.6 SL (1.8% BA + 1.8% GA4+7) and ASAHI SL (trade name Atonik – 0.3% sodium para-nitro-phenolan + 0.2% sodium orto-nitrophenolan + 0.1% sodium 5-nitrogujakolan) – each of them in concentrations of 0.1% and 0.2%. The most simulative effect on daughter plants formation was established for Gibrescol 10 MG (0.2%) and Promalin 3.6 SL (0.2%), results being quite similar for both preparations. These treatments increased the number of daughter plants by almost 300% as compared with the untreated control mother plants.