Genótipos seminais de matrizes antigas de Coffea canephora do sul do Espírito Santo: qualidade da bebida, diversidade genética, estrutura populacional e associação genômica ampla
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Data
2025-02-18
Autores
Silva, Matheus Alves
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Universidade Federal do Espírito Santo
Resumo
Conilon coffee (Coffea canephora Pierre ex A. Froehner) was introduced to southern Espírito Santo in the early 20th century. Since the 1990s, old plantations have been renewed with clonal varieties, potentially reducing the genetic base. Thus, characterizing and preserving historical germplasm is critical, as it represents a potential source of genetic variability for breeding programs. This study aimed to evaluate seed-propagated genotypes of C. canephora derived from selected parent plants of old plantations in southern Espírito Santo, focusing on three aspects: (i) sensory attributes, final scores, and sensory profiles; (ii) genetic diversity and population structure; (iii) genome-wide association study (GWAS) for beverage quality traits. The experiment was established in April 2018 in Mimoso do Sul (ES), using Federer’s augmented block design with 1,940 plants distributed into 388 half sibling families and five commercial clones as controls. Beverage quality was assessed in 172 genotypes over two production years (2022 and 2023). For genetic diversity and population structure analysis, 649 genotypes (447 from the experiment and 202 provided by other institutions, including Conilon, Robusta, and morphological intermediates) were evaluated using single nucleotide polymorphism (SNP) markers generated by DArTseq™. GWAS included 370 experimental genotypes. All genotypes achieved a "Fine" classification (mean score: 81.92; range: 80.81–84.08). Attributes such as uniformity and clean cup received maximum scores, indicating defect-free profiles. Genotype clustering resulted in 11 groups, with commercial clones distributed across two clusters. Forty-eight sensory profiles were identified within the flavor wheel, along with 25 additional profiles not represented in the wheel, with varying predominance. Significant correlations were observed between sensory attributes/profiles and final scores. For genetic diversity and population structure, six clusters and K = 3 ancestral groups were identified using 1,654 SNPs. Cluster 1 (523 genotypes) comprised most seed-propagated genotypes from old plantations and commercial varieties. Cluster 4, containing intermediate genotypes, exhibited high heterozygosity (0.37) and negative FIS (-0.73), suggesting outbreeding. High FST values (0.80 and 0.71) indicated strong genetic divergence between cluster 1 (predominantly Conilon) and clusters 5–6 (mostly Robusta), composed of distinct ancestral groups. GWAS identified 246 significantly associated SNPs: 68 for final score, 40 for fragrance/aroma, 34 for flavor, 19 for aftertaste, 21 for acidity/saltiness, 11 for mouthfeel, 22 for balance, 15 for bitterness/sweetness, and 16 for overall quality. Of these, 148 SNPs were located on chromosomes 1–11, with 83 situated in gene sequences. Putative gene functions were annotated, and some markers were associated with multiple traits. Collectively, the results underscore the potential of southern Espírito Santo’s remnant germplasm for C. canephora breeding programs, combining superior sensory quality with genetic diversity. These genotypes are strategic resources for germplasm banks, safeguarding diversity against future challenges. The identified chromosomal regions enable marker-assisted selection for key beverage traits, optimizing the development of elite cultivars through precise genomic tools.
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Café , Avaliação sensorial , Melhoramento genético , Coffee , Sensory evaluation , Genetic improvement