SEMINIFEROUS PROPAGATION OF Cordia oncocalyx (Allemão) Baill. AND BIOMETRIC CHARACTERIZATION OF DIASPORES AND SEEDS

ABSTRACT Cordia oncocalyx Allemão Baill., widely known as “pau-branco”, is a native species from the Caatinga (Brazilian Savannah) and has socioeconomic and environmental potential; however, there are few silvicultural studies on this species. Therefore, this paper aimed to analyze and compare the biometric characteristics of diaspores and seeds through manual biometrics and by digital image processing, and to evaluate the in vitro and ex vitro germination of C. oncocalyx. In the biometrics evaluation, three hundred diaspores and three hundred seeds were used, applying manual and digital biometrics. Subsequently, ex vitro emergence was determined, testing mechanical scarification (in different regions of the diaspore) and chemical scarification (immersion in sulfuric acid for 90 min and 180 min). Finally, in vitro germination was tested with different compositions of Murashige & Skoog (M&S) culture medium and sucrose addition. Results showed that digital image processing is a viable and fast technique to obtain the biometric parameters of C. oncocalyx fruit and seeds. Chemical and mechanical treatments on diaspores have not influenced seed emergence (0.33%). The composition of the culture medium has influenced the germination percentage, and the maximum value of 96% % was obtained with 6 g/L of sucrose and 0.90 g/L of M&S medium. Thus, the seminiferous propagation of C. oncocalyx can be performed successfully when the seeds are germinated in vitro, and the digital image processing shows the solidity and applicability aiming to evaluate the quantitative parameters of seed and fruit of this species. RESUMO Cordia oncocalyx Allemão Baill., conhecida popularmente como pau-branco, é uma espécie nativa da caatinga, com potencial socioeconômico e ambiental, entretanto, são escassos estudos silviculturais sobre a espécie. Portanto, objetivou-se analisar no presente trabalho as características biométricas dos diásporos e sementes por meio da biometria manual e pelo processamento digital de imagens, com o intuito de compará- las, bem como avaliar a germinação in vitro e emergência ex vitro de C. oncocalyx. Na avaliação da biometria, foram utilizados 300 diásporos e 300 sementes, aplicando-se a biometria manual e a digital. Posteriormente, foi realizada a emergência ex vitro, testando a escarificação mecânica (escarificação em diferentes regiões do diásporo) e química (imersão em ácido sulfúrico por 90 e 180 min). Por fim, testou-se a germinação in vitro, utilizando