PROSPECTING AND MORPHOLOGICAL CHARACTERIZATION OF BRAZILIAN PSIDIUM GERMPLASM

Abstract

A large germplasm prospecting expedition was carried out in different ecoregions in ten Brazilian States in order collect and characterize Psidium guajava L. and another Psidium species, known as araca. Ecogeographic sampling areas were defined based on eco-geographical zoning and vegetation maps. The accessions were characterized for 40 descriptors, according to the International Union for the Protection of New Varieties of Plants guidelines. One hundred and nineteen guava accessions and 40 araca accessions araca were sampled and characterized in 35 different Brazilian ecoregions. The most invariable descriptors for both guava and araca were color of young shoots, leaf pubescence on lower side, leaf blade length and width, leaf variegation, fruit surface relief, fruit longitudinal ridges and grooves and evenness of fruit flesh color. The large majority of araca accessions presented widely spaced leaf veins, contrasting with the guava accessions that presented medium to close spacing. Most fruits of araca accessions were classified as small, while most fruits of guava accessions were grouped into the class of medium size. For the fruit flesh color, 91% araca were grouped as cream and white, while 58% guava accessions presented pale pink, pink and dark pink coloring. These fruit differences among wild Psidium species and guava suggested that the fruit traits have been the most altered trait by artificial selection.