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ORIGINAL RESEARCH article

Front. Plant Sci.
Sec. Plant Breeding
Volume 15 - 2024 | doi: 10.3389/fpls.2024.1408239

High density linkage to physical mapping in a unique Tall x Dwarf Coconut (Cocos nucifera L.) outbred F2 uncovers a major QTL for flowering time colocalized with the FLOWERING LOCUS T (FT)

Provisionally accepted
Dario Grattapaglia Dario Grattapaglia 1,2*Wellington B. Alves Wellington B. Alves 1,2Cleso A. Pacheco Cleso A. Pacheco 3
  • 1 Embrapa Genetic Resources and Biotechnology, Brasília, Brazil
  • 2 Departamento de Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil
  • 3 Embrapa Tabuleiros Costeiros, Aracaju, Brazil

The final, formatted version of the article will be published soon.

    The coconut tree crop (Cocos nucifera L.) provides vital resources for millions of people worldwide. Coconut germplasm is largely classified into 'Tall' (Typica) and 'Dwarf' (Nana) types. While Tall coconuts are outcrossing, stress tolerant and late flowering, Dwarf coconut are inbred, flower early with a high rate of bunch emission.Precocity determines earlier production of a plantation and facilitates management and harvest.Methods: We used a unique outbred F2 population generated by intercrossing F1 hybrids between Brazilian Green Dwarf from Jiqui (BGDJ) and West African Tall (WAT) cultivars.SNP markers fixed for alternative alleles in the two varieties, segregating in an F2 configuration were used to build a high-density linkage map with ~3,000 SNPs, anchored to the existing chromosome-level genome assemblies, and a QTL mapping analysis was carried out.The linkage map established the chromosomes numbering correspondence between the two reference genome versions and the relationship between recombination rate, physical distance and gene density in the coconut genomes.Leveraging the strong segregation for precocity inherited from the Dwarf cultivar in the F2, a major effect QTL with incomplete dominance was mapped for flowering time.involved in flowering time by alternative splice variant analysis, were colocalized within a ~200kb window of the major effect QTL (LOD=11.86).Discussion: Our work provides strong phenotype-based evidence for the role of the FT locus as the putative underlying functional variant for the flowering time difference between Dwarf and Tall coconuts. Major effect QTLs were also detected for developmental traits of the palm, plausibly suggesting pleiotropism of the FT locus for other precocity traits. Haplotypes of the two SNPs flanking the flowering time QTL inherited from the Dwarf parent BGDJ caused a reduction in the time to flower of around 400 days. These SNPs could be used for high throughput marker assisted selection of early flowering and higher productivity recombinant lines, providing innovative genetic material to the coconut industry.

    Keywords: Coconut, Flowering locus T, Hybrid breeding, snps, flowering

    Received: 27 Mar 2024; Accepted: 06 May 2024.

    Copyright: © 2024 Grattapaglia, Alves and Pacheco. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Dario Grattapaglia, Embrapa Genetic Resources and Biotechnology, Brasília, 70770-901, Brazil

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