Determination of the optimal culture medium and growth regulator concentration for the in vitro proliferation stage of the peach-almond hybrid MayorReg..

摘要

This work studies the in vitro proliferation stage of the peach-almond hybrid 'Mayor'Reg., by comparing the proliferation rates, height and number of leaves of the explants, together with the number of explants exhibiting hyperhydricity symptoms, and the qualitative states (0-4), in four culture media: Murasighe and Skoog, MS (1976); Lloyd and McCown, WPM (1980); Driver and Kuniyuki, DKW (1984) and the culture media created specifically for this hybrid (ME) by our research team (Cos and Frutos, 2000). The concentrations of growth regulator used were 1 mg/l of Benzylaminopurine [benzyladenine] (BAP)+0.1 mg/litre of Indolyl butyric acid (IBA), 30 g/litre of sucrose and 7 g/litre of Bacto Agar Difco. Once the optimal culture medium for this stage was determined, we studied different growth regulator concentrations: BAP=0.5, 1 and 1.5 mg/litre, with and without 0.1 mg/litre of IBA, and later 0.2 mg/litre of GA3 was added. The results obtained show that the best culture media was the specific (ME) medium with a proliferation rate of 5.21 explants; there were significant differences when compared to the other three media. Also, the height, number of leaves and the qualitative states in the specific media were greater, and the hyperhydricity symptoms were less in this media. With respect to the growth regulator study, the best proliferation rates were obtained with 1 and 1.5 mg/l of BAP+0.1 mg/l of IBA, which produced similar quality explants, although when using 1 mg/l of BAP+0.1 mg/l of IBA, the hyperhydricity symptoms were reduced, and for this reason it was considered the optimal concentration. The addition of 0.2 mg/l of GA3 gave poorer proliferation results, although it caused an increase in the height of the explants produced.