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Cacao genotypes cultivated in agroforestry systems in Bahia have wide genetic variability in morpho-agronomic characters

ABSTRACT Cacao fruits are agronomically important and show wide variability for several morphological descriptors. The present study aimed to characterize the genetic distance of 51 genotypes of Theobroma cacao L. in the cocoa-producing region of Southern Bahia (Brazil) based on morpho-agronomic des...

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Bibliographic Details
Published in:Ciência e agrotecnologia 2023-01, Vol.47
Main Authors: Georges, Marc Ernso, Melo, Cláusio Antônio Ferreira, Souza, Margarete Magalhães de, Corrêa, Ronan Xavier
Format: Article
Language:English
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Summary:ABSTRACT Cacao fruits are agronomically important and show wide variability for several morphological descriptors. The present study aimed to characterize the genetic distance of 51 genotypes of Theobroma cacao L. in the cocoa-producing region of Southern Bahia (Brazil) based on morpho-agronomic descriptors. The inference of genetic similarity was performed from the phenotypic data derived simultaneously from qualitative and quantitative variables, using the Ward-MLM procedure (Modified Location Model) with the SAS® software. The distance matrix was obtained using the Gower logarithmic function. For this, 28 descriptors were evaluated, five qualitative and 23 quantitative. Furthermore, using the likelihood function procedure, the optimal number of groups was five indicating wide variability. Of 23 quantitative descriptors evaluated by fruits and leaves, 95% showed significant differences. The exception was seed width. Groups 1 and 5 were the most distant, while groups 2, 3, and 4 were closest to each other. The greatest difference between increments was 35.32 for the fifth group. The analysis of the first two canonical axes revealed that both represented 81.88% of the variation, with CAN1 and CAN2 responsible for 53.66% and 28.22% of the variation. The most promising genotypes for breeding programs belong to group 5 due to their superior performance for almost all characteristics analyzed. RESUMO Os frutos de cacau são de grande importância agronômica e apresentam ampla variabilidade em vários descritores morfológicos. O presente estudo teve como objetivo caracterizar a distância genética de 51 genótipos de Theobroma cacao L. na região produtora de cacau do Sul da Bahia (Brasil) com base em descritores morfo-agronômicos. A inferência de similaridade genética foi realizada a partir dos dados fenotípicos derivados simultaneamente de variáveis qualitativas e quantitativas, utilizando o procedimento Ward-MLM (Modified Location Model) com o software SAS®. A matriz de distância foi obtida utilizando a função logarítmica de Gower. Para isso, 28 descritores foram avaliados, cinco qualitativos e 23 quantitativos. Além disso, usando o procedimento de função de verossimilhança, o número ótimo de grupos foi cinco, indicando ampla variabilidade. Dos 23 descritores quantitativos avaliados em frutos e folhas, 95% apresentaram diferenças significativas, exceto a largura da semente. Os grupos 1 e 5 foram os mais distantes, enquanto os grupos 2, 3 e 4 foram mais próximos. A
ISSN:1413-7054
1981-1829
1981-1829
DOI:10.1590/1413-7054202347004923