Morphological and phenological description of 38 sweet chestnut cultivars (Castanea sativa Miller) in a contemporary collection

Thirty eight traditional chestnut cultivars, from a contemporary collection, were described using nine characteristics, seven of which are included in the guidelines for carrying out tests of distinctness, homogeneity and stability of chestnut established by the International Union for the Protection of New Varieties of Plants (UPOV). The nine variables were chosen from among 13 characteristics evaluated in the collection with regard to the criteria for distinctness, uniformity and stability. The evaluations were carried out over the years 2003, 2004 and 2005, in two plantations, situated in the northwest of the Iberian Peninsula. Each mean value obtained for each cultivar, plantation and year were assigned a state and numerical number using the UPOV system or proposed new descriptors. No cultivar showed a very late time of leaf bud burst nor a very late time for the start of male and female flowering, nor a strong penetration of the seed coat into embryo. In five variables there was no or few differences among years and between plantations. Consequently they can be evaluated at one site in one year. These characters were: filament length of male flowers, percent of chestnuts with a split pericarp, the degree of penetration of the seed coat into the embryo, fruit shape and the ratio of hilum length to hilum width. Of the remaining four variables, three were phenological (time of leaf bud burst, time of beginning of male and female flowering) and one related to fruit size (size of fruit hilum). They varied among years and between plantations and consequently need to be evaluated under contrasting site conditions for a minimum number of years.