Anatomical diversity of five biotypes of the species Theobroma cacao(cacao) in the southern region of Ecuador

Abstract

Agrobiodiversity includes variability at the specific and genetic level, its dynamics and relationships between cultivated plants and their wild relatives. The Theo b ro m a c a c aoL. species has a high cultural and economic value inEcuador because it helps around 100,000 rural families. However, the structure of its wood and the variability of microscopic characteristics between its biotypes is unknown. For this reason, this study seeks to fill th is gap with an anatomical analysis of the wood in its three planes (transverse, tangentia l, a n d radial) according to IAWA regulations in five biotypes of T. cocoa (aromático, criollo, forastero, trinitario y CCN51) from the Piuntza and Guayzimi sectors of the province of Zamora Chinchipe. Itwas found that all biotypes presented simple perforation plates, alternating polygonal pits, diffuse axial parenchyma, multiseriate and uniseriate ra y s , ra y s with procumbent cells of 2-4 rows of vertical and / or marginal square cells,h ow e ve r, th e prismatic crystals, drusen, envelope cells, and perforated radial cells were variable. At a quantitative level, the highest radii were found mainly in the creole and fore ign b io ty pe s , while the CCN51 and trinitariobiotypes obtained higher values in vessels per square millimeter. With this, it was shown that all the individuals analyzed, despite being of the same species, had anatomical differences, which shows that the microscopic study of woo d is a very useful tool for the identification of biotypes within a species.Keywords:Wood anatomy, cacao, biotype, IAWA, agrobiodiversity