Provenance and tree-to-tree differences in germination performance of Balanites aegyptiaca (L.) Delile: Insights for domestication and selection

초록

Identifying the best genetic material across provenances and genotypes, particularly for vigorous seedling production, is a key aspect of domestication programs. This study aimed to (i) assess provenance and tree-to-tree differences in the germination performance of Balanites aegyptiaca and (ii) identify mother trees with the best germination performance for seed sourcing. A total of 1440 ripe fruits were collected from 36 mother trees in two provenances (Karimama and Tanguieta) in Benin and one provenance (Mouhoun) in Burkina Faso. A germination trial was conducted using a split-plot design over 30 days. Differences among provenances and trees were assessed based on three metrics of germination performance: final germination percentage (FGP), mean germination time (MGT), and germination index (GI), using generalized linear models and linear mixed-effects models. Phenotypic variability, heritability, and genetic advance of B. aegyptiaca based on these metrics were further evaluated. Results showed that FGP, MGT, and GI varied significantly among provenances. FGP and GI exhibited considerable variation among provenances (44.7 and 38.9 %, respectively) and among mother trees (48.2 and 46.7 %, respectively). High phenotypic coefficient of variation (> 67 %), genotypic coefficient of variation (> 63 %), broad-sense heritability (> 80 %), and genetic gain (> 100 %) were observed for FGP and GI, indicating significant additive genetic effects for these metrics. Eight mother trees from Mouhoun, four from Karimama, and four from Tanguieta were identified as the best performers based on final germination percentage. Our study showed that selection based on FGP and GI can be used to identify elite genotypes for domestication and improvement programs for B. aegyptiaca. © 2025 The Authors

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