Cacao is a crop of global relevance that faces constant demands for improved bean yield.However,little is known about the genomic regions controlling the crop yield and genes involved in cacao bean filling.Hence,to id...Cacao is a crop of global relevance that faces constant demands for improved bean yield.However,little is known about the genomic regions controlling the crop yield and genes involved in cacao bean filling.Hence,to identify the quantitative trait loci(QTL)associated with cacao yield and bean filling,we performed a QTL mapping in a segregating mapping population comprising 459 trees of a cross between‘TSH 1188’and‘CCN 51’.All variables showed considerable phenotypic variation and had moderate to high heritability values.We identified 24 QTLs using a genetic linkage map that contains 3526 single nucleotide polymorphism(SNP)markers.Haplotype analysis at the significant QTL region on chromosome IV pointed to the alleles from the maternal parent,‘TSH 1188’,as the ones that affect the cacao yield components the most.The recombination events identified within these QTL regions allowed us to identify candidate genes that may take part in the different steps of pod growth and bean filling.Such candidate genes seem to play a significant role in the source-to-sink transport of sugars and amino acids,and lipid metabolism,such as fatty acid production.The SNP markers mapped in our study are now being used to select potential highyielding cacao varieties through marker-assisted selection in our existing cacao-breeding experiments.展开更多
We have characterized the number of ovules per ovary (NoOV) in cacao plants originated from crossing the clones CCN 51 and TSH 1188 (segregating progeny) and determined the heritability of this characteristic in order...We have characterized the number of ovules per ovary (NoOV) in cacao plants originated from crossing the clones CCN 51 and TSH 1188 (segregating progeny) and determined the heritability of this characteristic in order to select plants with higher NoOV in this progeny. The NoOV was calculated as the average of 10 flowers per plant and ranged from 44.8 to 58.6 between the six clones (two parents and four clones belonging to their genealogy). In the progeny (n = 209 plants) the NoOV averaged 54.3 (range 44.1 to 67.8). The NoOV was distributed uniformly among the progeny indicating that this trait is conditioned by polygenes. Its heritability was estimated at 67.7%. The 32 plants with NoOV similar or superior to the genitor CCN 51 (highest amount among clones) were selected for use in the genetic improvement program. We showed that this population is suitable for genetic mapping, molecular marker identification and selection of superior cacao genotypes.展开更多
文摘Cacao is a crop of global relevance that faces constant demands for improved bean yield.However,little is known about the genomic regions controlling the crop yield and genes involved in cacao bean filling.Hence,to identify the quantitative trait loci(QTL)associated with cacao yield and bean filling,we performed a QTL mapping in a segregating mapping population comprising 459 trees of a cross between‘TSH 1188’and‘CCN 51’.All variables showed considerable phenotypic variation and had moderate to high heritability values.We identified 24 QTLs using a genetic linkage map that contains 3526 single nucleotide polymorphism(SNP)markers.Haplotype analysis at the significant QTL region on chromosome IV pointed to the alleles from the maternal parent,‘TSH 1188’,as the ones that affect the cacao yield components the most.The recombination events identified within these QTL regions allowed us to identify candidate genes that may take part in the different steps of pod growth and bean filling.Such candidate genes seem to play a significant role in the source-to-sink transport of sugars and amino acids,and lipid metabolism,such as fatty acid production.The SNP markers mapped in our study are now being used to select potential highyielding cacao varieties through marker-assisted selection in our existing cacao-breeding experiments.
文摘We have characterized the number of ovules per ovary (NoOV) in cacao plants originated from crossing the clones CCN 51 and TSH 1188 (segregating progeny) and determined the heritability of this characteristic in order to select plants with higher NoOV in this progeny. The NoOV was calculated as the average of 10 flowers per plant and ranged from 44.8 to 58.6 between the six clones (two parents and four clones belonging to their genealogy). In the progeny (n = 209 plants) the NoOV averaged 54.3 (range 44.1 to 67.8). The NoOV was distributed uniformly among the progeny indicating that this trait is conditioned by polygenes. Its heritability was estimated at 67.7%. The 32 plants with NoOV similar or superior to the genitor CCN 51 (highest amount among clones) were selected for use in the genetic improvement program. We showed that this population is suitable for genetic mapping, molecular marker identification and selection of superior cacao genotypes.
