of indole-3-butyric acid (IBA). The highest shoot initiation rates were achieved with apple cultivar "Principe Grande" (55%) and "Barburiña" pear cultivar (50%); the lowest rate was obtained with apple cultivar "Camoesa" (11%). Initiation rates for shoots culture varied between 22% and 37% for the other cultivars. The cytokinins BA, zeatin, 2-isopentyladenine (2iP) and thidiazuron (

Heat therapy followed by the isolation and in vitro culture of apical meristems is a suitable procedure for virus eradication. However, the period of heat treatment is usually long (28 -50 days) and the yield of viable plants free of viruses after treatment is often low (<50%). Here, we describe an alternative method to obtain virus-free plants. We used traditional Galician cultivars, six apple trees and two pear trees, infected with Apple chlorotic leaf spot virus (ACLSV) and Apple mosaic virus (ApMV). We combined heat therapy of in vitro shoots using a temperature gradient from 25˚C to 40˚C increasing 1˚C per day for a shorter period of time (18 days) with the posterior isolation and culture of apical meristems. All DNA samples analyzed, obtained from plants developed from meristems, were 100% free of ApMV and almost 90% free of ACLSV. With this in vitro procedure combined we obtained a good yield of tested plants free of viruses. Our method is fast and effective and it could be also useful to eradicate these and other viruses in other fruit trees.

The description of phenotypic traits in apple cultivars is generally performed using internationally agreed descriptors such as UPOV guidelines, which defines for each trait several states of expression. However, it is not always possible to classify a cultivar unambiguously using those guidelines, because in practice the states are not clearly enough defined or the example varieties used to clarify the different states are not available in the collection. This work presents the results of a harmonization project performed by the teams responsible of the main apple germplasm collections in Spain. The objective was to develop a standardized method for the 57 traits included in the TG/14/9 UPOV guidelines for apple characterization, defining their states of expression in a clear and unambiguous way for Spanish germplasm. Phenotypic data collected for more than 1,600 accessions from Spanish collections was used and the method to define each state depended on the type of expression. For quantitative traits the number of states and their limits were defined according to the variability that exists within and between accessions. For qualitative traits, highresolution images clearly depicting each state were selected. A standardized characterization protocol for the 57 traits of apple germplasm has been provided, enabling to comparing properly the phenotypes of Spanish genetic resources.