Martínez-Gómez, P., Depto. de Mejora y Patol. Vegetal, CEBAS-CSIC, P.O. Box 164, E-30100 Espinardo (Murcia), Spain
Sánchez-Pérez, R., Depto. de Mejora y Patol. Vegetal, CEBAS-CSIC, P.O. Box 164, E-30100 Espinardo (Murcia), Spain
Vaknin, Y., Department of Pomology, University of California, Davis, CA, United States
Dicenta, F., Depto. de Mejora y Patol. Vegetal, CEBAS-CSIC, P.O. Box 164, E-30100 Espinardo (Murcia), Spain
Gradziel, T.M., Department of Pomology, University of California, Davis, CA, United States

In almond [Prunus dulcis (Mill.) D.A. Webb], there are few chromosome studies. In this work, different methods described for slide preparation and staining of chromosomes in other Prunus species have been evaluated using almond root tips. By modifying and updating traditional methods, an improved technique for counting chromosomes has been developed. Root tips were first placed in cold water for 4 h at 0°C and treated with 0.2% colchicine for 3 h at 5°C. They were then fixed for 24 h at 5°C in methanol, propionic acid, chloroform (6:3:2), and stored in 70% ethanol. This optimized protocol allowed the identification of chromosomes in the different stages of mitosis late prophase being the best stage for chromosome counting. © 2005 Elsevier B.V. All rights reserved.