Heterosis in Crosses of <i>Theobroma cacao</i>

Atanda, O. A.

doi:10.1017/s0014479700023632

Cited by 6 publications

(4 citation statements)

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“…They could be tested as parents of hybrids aiming to reduce variability in operational plantations and potentially exploit hybrid vigor in a more systematic way. A number of studies have shown a strong influence of dominance variance on cacao yield, supporting the dominance hypothesis for heterosis [ 15 , 53 , 62 – 65 ]. Additionally, a relationship between multivariate genetic divergence based on phenotypic traits with combining ability effects was reported in cacao, with the most divergent cultivar exhibiting high general combining ability, producing the best performing hybrids [ 66 ].…”

Section: Discussionmentioning

confidence: 83%

“…The use of inbred lines as parents of hybrids could minimize the problems associated with both, clonal propagation and interclonal hybrid variability, by consolidating the advantages of both deployment methods, i.e., seed propagation and capture of hybrid vigor. This was attempted since the beginning of hybrid breeding in cacao by searching for naturally inbred selections from local populations (e.g., Amelonado, Matina) [ 10 – 13 ], using partially inbred lines [ 11 , 13 – 15 ], looking for spontaneous haploids to be diploidized [ 16 ] and through the use of anther culture [ 17 – 19 ]. All these strategies ultimately try to overcome the challenge associated with the production of fully inbred parents in cacao by the traditional method of successive self-fertilizations, a lengthy process, given the long generation time in cacao (3–5 years/generation) and large experimental area required (commonly 9 m 2 /tree).…”

Section: Introductionmentioning

confidence: 99%

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Genome-wide SNP genotyping as a simple and practical tool to accelerate the development of inbred lines in outbred tree species: An example in cacao (Theobroma cacao L.)

Lopes

Pires²,

Gramacho³

et al. 2022

PLoS ONE

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Cacao is a globally important crop with a long history of domestication and selective breeding. Despite the increased use of elite clones by cacao farmers, worldwide plantations are established mainly using hybrid progeny material derived from heterozygous parents, therefore displaying high tree-to-tree variability. The deliberate development of hybrids from advanced inbred lines produced by successive generations of self-pollination has not yet been fully considered in cacao breeding. This is largely due to the self-incompatibility of the species, the long generation cycles (3–5 years) and the extensive trial areas needed to accomplish the endeavor. We propose a simple and accessible approach to develop inbred lines based on accelerating the buildup of homozygosity based on regular selfing assisted by genome-wide SNP genotyping. In this study we genotyped 90 clones from the Brazilian CEPEC´s germplasm collection and 49 inbred offspring of six S1 or S2 cacao families derived from self-pollinating clones CCN-51, PS-13.19, TSH-1188 and SIAL-169. A set of 3,380 SNPs distributed across the cacao genome were interrogated on the EMBRAPA multi-species 65k Infinium chip. The 90 cacao clones showed considerable variation in genome-wide SNP homozygosity (mean 0.727± 0.182) and 19 of them with homozygosity ≥90%. By assessing the increase in homozygosity across two generations of self-pollinations, SNP data revealed the wide variability in homozygosity within and between S1 and S2 families. Even in small families (<10 sibs), individuals were identified with up to ~1.5 standard deviations above the family mean homozygosity. From baseline homozygosities of 0.476 and 0.454, offspring with homozygosities of 0.862 and 0.879 were recovered for clones TSH-1188 and CCN-51 respectively, in only two generations of selfing (81–93% increase). SNP marker assisted monitoring and selection of inbred individuals can be a practical tool to optimize and accelerate the development of inbred lines of outbred tree species. This approach will allow a faster and more accurate exploitation of hybrid breeding strategies in cacao improvement programs and potentially in other perennial fruit and forest trees.

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Section: Discussionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Genome-wide SNP genotyping as a simple and practical tool to accelerate the development of inbred lines in outbred tree species: An example in cacao (Theobroma cacao L.)

Lopes

Pires²,

Gramacho³

et al. 2022

PLoS ONE

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show abstract

“…Além disso, as variedades diferem em percentagem de umidade, contribuindo para reduzir a efe tividade deste componente, como parâmetro discriminador (BARTLEY, 1967). Ainda assim, POUND (1932a, 1932b, 1933) (RUINARD, 1961;ATANDA, 1972a;ESKES et alii, 1977;ENGELS, 1983). Existe alta correlação entre o número de frutos produzidos e o peso total de sementes ú midas (GLENDINNING, 1963;ESQUIVEL & SORIA, 1967;ATANDA & TOXOPEUS, 1971;ATANDA, 1972a) e entre os primeiros e a pr� dução de sementes secas (ESQUIVEL & SORIA, 1967).…”

Section: Revisão De Literaturaunclassified

“…O sucesso do milho hibrido motivou a realiza ção de intensas pesquisas em outras espécies, em busca de respostas heter6ticas para caracteres de interesse. Na cul tura do cacau, diversos autores (RUSSEL, 1952;SORIA, 1964;OPEKE & JACOB, 1969;ATANDA & TOXOPEUS, 1971;REYES & PEREZ, 1971;ATANDA, 1972bATANDA, , 1973…”

Section: Com Respeito àS Correlações Genéticas Calcuunclassified

Repetibilidade e capacidade de combinação em cacau >i<Theobroma cacao>/i< L.) nas condições do Sul da Bahia

Dias

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Combining-ability for cacao (Theobroma cacao L.) yield components under southern Bahia conditions

Dias¹,

Kageyama²

1995

Theoret. Appl. Genetics

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The objective of this study was to assess five cacao cultivars (selfs) and 20 hybrids with regard to their general-and specific-combining ability for yield components using method 1, model I, of the diallel analysis system. The selfings and the hybrids were obtained through controlled crossings, tested in the field in a random block design with four replications and plots containing 16 plants. The experiment was set up in the Centro de Pesquisas do Cacau, in Itabuna, Bahia, Brasil, in 1975. The characteristics studied were: the number of healthy and collected fruits per plant (NHFP and NCFP), the weight of humid seeds per plant and per fruit (WHSP and WHSF), and the percentage of diseased fruits per plant (PDFP), for 5 years (1986-1990). The F-test values, highly significant for general combining ability (GCA) and specific combining ability (SCA), demonstrated the existence of variability for both effects. However, the effects of SCA were greater than those of GCA, when compared in terms of the average squared effects. This condition held for the characteristics NHFP, NCFP and WHSP, which shows the relative importance of the non-additive genetic effects over the additive effects. The reciprocal effects did not show significance. Breeding methods which explore the additive portion of genetic variance should be employed for obtaining higher-yielding cacao and high seed weight. For this, the segregant populations should involve cultivars CEPEC 1, SIAL 169 and ICS 1. Combinations involving the cultivar ICS 1 presented the most favorable results for the characteristics WHSP and WHSF, where the hybrid SIAL 169 x ICS 1 and its reciprocal were outstanding.

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Heterosis in Crosses of Theobroma cacao

Cited by 6 publications

References 6 publications

Genome-wide SNP genotyping as a simple and practical tool to accelerate the development of inbred lines in outbred tree species: An example in cacao (Theobroma cacao L.)

Genome-wide SNP genotyping as a simple and practical tool to accelerate the development of inbred lines in outbred tree species: An example in cacao (Theobroma cacao L.)

Repetibilidade e capacidade de combinação em cacau >i<Theobroma cacao>/i< L.) nas condições do Sul da Bahia

Combining-ability for cacao (Theobroma cacao L.) yield components under southern Bahia conditions

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