DIFFERENTIATION AMONG CHESTNUT CULTIVARS USING ADAPTATIVE AND MORPHOLOGICAL TRAITS

Following a forest inventory carried out up to 1989 in Galician chestnut plantations and the in situ characterization carried out by CIFA Lourizán (Pontevedra), a germplasm bank was set up in 1997 at two sites, in an area of northwestern Spain characterised by Atlantic climate, using the most interesting and representative material (138 clones of 52 varieties and two repetitions by clone and site). The objective of the present study was the ex situ characterization of these traditionally used productive varieties of Galician chestnut. More specifically the descriptive values of 39 morphological and phenological characters were established in chestnut cultivars in order to 1) find out which are influenced by the environment and how, and 2) determine which characters are under genetic control (show heritability) and which can be considered as descriptors, according to the UPOV criteria of distinctness, uniformity and stability. The following variables were found to be useful as descriptors: among morphological characters of male catkins, the length and the type; among leaf morphological characters, the length, the ratio of width/length, the blade length, and the blade length/width ratio; and among fruit morphological characters, the relative size of hilum in relation to chestnut. All of these characters show a high degree of broad-sense heritability.