Retrospective Determination of the Parental Population of Superior Cacao (Theobroma cacao L.) Seedlings and Association of Microsatellite Alleles with Productivity

Abstract

<jats:p>Commercial production of cacao in Hawaii is increasing, and this trend is expected to continue over the next several years. The increased acreages are being planted with seedlings from introduced and uncharacterized cacao populations from at least three initial introductions of cacao into the islands. Productive seedlings have been selected from a planting at Waialua, Oahu. The parents of these selections were believed to be the population at the Hawaii Agriculture Research Center (HARC) at Kunia; however, potential parental populations also exist at Univ. of Hawaii research stations at Waimanalo and Malama Ki. Using microsatellite markers, we analyzed the potential parental populations to identify the parents and determine the genetic background for 99 productive and 50 unproductive seedlings from the Waialua site. Based on 19 polymorphic microsatellite loci the parental population was identified as trees from Waimanalo and not trees from Malama Ki or Kunia. The Kunia and Malama Ki populations were very similar with low allelic diversity (A = 1.92) and low unbiased gene diversity (H<jats:sub>nb</jats:sub>) of 0.311 and 0.329, respectively, and were determined to be Trinitario in type. The Waimanalo, productive seedling, and unproductive seedling populations had much higher levels of genetic diversity with H<jats:sub>nb</jats:sub> of 0.699, 0.686, and 0.686, respectively, and were determined to be upper Amazon Forastero hybridized with Trinitario in type. An additional 46 microsatellite markers were amplified and analyzed in the Waimanalo parents, productive, and unproductive seedlings for a total of 65 loci. Seventeen loci contained alleles that were significantly associated with productive seedlings as determined by Armitage's trend test. Of these, 13 loci (76.4%) co-located with previously reported quantitative trait loci for productivity traits. These markers may prove useful for marker assisted selection and demonstrate the potential of association genetic studies in perennial tree crops such as cacao.</jats:p>

Molecular characterization of an earliest cacao (Theobroma cacao L.) collection from Upper Amazon using microsatellite DNA markers

“…The development of simple sequence repeat (SSR) markers in cacao (Lanaud et al 1999) has significantly increased the capacity of molecular characterization of cacao germplasm. SSRbased DNA fingerprinting has been increasingly applied in cacao germplasm characterization (Aikpokpodion et al 2005;Cryer et al 2006;Efombagan et al 2008;Johnson et al 2007;Lanaud et al 2001;Motamayor et al 2002Motamayor et al , 2008Schnell et al 2005;Sereno et al 2006;Zhang et al 2008Zhang et al , 2009. These studies generate important information relating to the genetic diversity and the origin of the crop.…”

Microsatellite variation and population structure in the “Refractario” cacao of Ecuador

“…Since the development of simple sequence repeat (SSR) markers for cacao (Lanaud et al 1999), SSR-based DNA fingerprinting has been increasingly applied in cacao germplasm characterization (Charters and Wilkinson 2000; Lanaud et al 2001;Motamayor et al 2002Motamayor et al , 2003Saunders et al 2001Saunders et al , 2004Cryer et al 2006;Schnell et al 2005;Takrama et al 2005). However, application of molecular markers for large-scale genotyping of genebank collection and comprehensive characterization of whole germplasm groups has been scarce.…”

Molecular characterization of an international cacao collection using microsatellite markers

“…"Identical" clones are declared when the similarity reaches certain threshold values (Christopher et al 1999;Perry et al 1998;Sounigo et al 2001). Since the development of simple sequence repeats (SSR) markers in cacao (Lanaud et al 1999), SSR-based DNA fingerprinting has been increasingly applied in cacao germplasm characterization (Lanaud et al 2001;Motamayor et al 2002;Saunders et al 2004;Cryer et al 2006;Schnell et al 2005;Takrama et al 2005). To date, however, reports have been scarce on large scale application of SSR markers to identify duplicate clones and assess the structure of genetic diversity in cacao genebanks.…”