Genetic evaluation and selection of cocoa tree clones

• Published in: Ciência rural 2022-01, Vol.52 (12)
• Main Authors: Guimarães, Maria Eduarda da Silva, Dias, Luiz Antônio dos Santos, Almeida, Caio Márcio Vasconcellos Cordeiro de, Souza, Carlos Alberto Spaggiari, Almeida, Odimar Ferreira, Benjamin, Carolina Santos, Pereira, Guilherme Rodrigues, Dias, Fernando José dos Santos, Corrêa, Thais Roseli
• Format: Article
• Language: English
• Subjects: AGRONOMY; genetic resources; genetic variability; germplasm characterization; plant breeding; Theobroma cacao L
• ISSN: 0103-8478; 1678-4596; 1678-4596
• DOI: 10.1590/0103-8478cr20210433

The cultivation of cocoa is of great socio-economic importance worldwide. Cocoa beans are the essential raw material for chocolate production. The variability of cacao studied presents only a small fraction of the existing genetic diversity, mainly in the Amazon region. Furthermore, just a small part of this variability has been exploited in cocoa breeding. Thus, the present study processed the genetic evaluation and selection of cocoa clones, based on morpho-agronomical traits. For this, we evaluated 145 clones, during 37 harvests from, four consecutive years. The following traits were evaluated: total number of fruits collected (TNFC), total number of healthy fruits (TNHF), weight of wet seeds from healthy fruits (WWSHF), average weight of wet seeds per healthy fruit (AWWSHF), weight of dry seeds from healthy fruit (WDSHF), average weight of dry seeds per healthy fruit (AWDSHF), percentage of fruits with witches’ broom disease (PFWB), percentage of fruits with borer (PFBR), percentage of fruits with germinated seeds (PFGS), number of branches with witches’ broom disease (NBWB), and number of inflorescence with witches’ broom disease (NIWB). Significant differences (P < 0.05) among the clones were observed for all traits, which reveal an expressive variability and possibility of gains with selection. The highest significant correlations (P < 0.05) occurred between traits TNFC and TNHF (0.94), TNHF and AWWSHF (0.86), and TNHF and AWDSHF (0.86). Based on the selection index, the clones POUND 12 and CAB 12, 228, 253, 257, 258, and 422 were the most suitable for selection. RESUMO: O cultivo do cacau tem grande importância socioeconômica mundial. Os amêndoas de cacau são a matéria-prima essencial para a produção de chocolate. A variabilidade do cacaueiro avaliada representa apenas uma pequena fração da diversidade genética existente, principalmente na região amazônica. Além disso, apenas uma pequena parte dessa variabilidade foi explorada no melhoramento de cacau. Dessa forma, o presente estudo teve como objetivo realizar a avaliação genética e seleção de clones de cacau, com base em características morfo-agronômicas. Para isso, foram avaliados 145 clones, durante 37 colheitas, em quatro anos consecutivos. As seguintes características de frutos e sementes foram avaliadas: número total de frutos colhidos (NTFC), número total de frutos sadios (NTFS), peso de sementes úmidas dos frutos sadios (PSUFS), peso médio de sementes úmidas dos frutos sadios (PMSUFS), peso