Determination of macronutrients to be included in in vitro culture media according to leaf concentrations

Because of the great number of in vitro culture media used in micropropagat ion, the present work proposes a method that optimizes and systematizes the macronutrient concentration to be used in a given medium. The method consi sts of adding the macronutrients that the leaves contain in the period of m aximum growth to the culture medium, since this should provide the best nut ritional conditions. We compared the proliferation stage of six spontaneous peach-almond hybrids (Mayor, Cieza 1, Cieza 2, Cieza 3, Cieza 4 and Cieza 5) and 'Mirobolan Adara' in the specific medium obtained from each selectio n as a function of its own leaf macronutrient content and the macronutrient of the widely used Murashige and Skoog (MS) medium. The growth regulator c oncentration in all cases was 1 mg l(-1) BAP and 0.1 mg l(-1) IBA, obtainin g higher proliferation rates, height and number of leaves and lower hyperhy dricity symptoms in the specific media in all the rootstock selections than in control MS.