A qNMR approach for bitterness phenotyping and QTL identification in an F1 apricot progeny

In apricot the bitter flavor of seeds is determined by the amount of amygdalin, a cyanogenic glucoside whose cleavage by endogenous enzymes, upon seed crushing, releases toxic hydrogen cyanide. The presence of such a poisonous compound is an obstacle to the use and commercialization of apricot seeds for human or animal nutrition. To investigate the genetic loci involved in the determination of the bitter phenotype a combined genetic and biochemical approach was used, involving a candidate gene analysis and a fine phenotyping via quantitative nuclear magnetic resonance, on an F1 apricot progeny. Seven functional markers were developed and positioned on the genetic maps of the parental lines Lito and BO81604311 and seven putative QTLs for the bitterness level were determined. In conclusion, this analysis has revealed some loci involved in the shaping of the bitterness degree; has proven the complexity of the bitter trait in apricot, reporting an high variance of the QTLs found over the years; has showed the critical importance of the phenotyping step, whose precision and accuracy is a pre-requisite when studying such a multifactorial character.

► 7 new functional markers developed on 3 genes of the CNGs metabolism were mapped.
► 3 putative QTLs were found in both parents.
► Precise phenotyping is crucial for an accurate QTL analysis.
► Bitterness in apricot has been proven to be a complex trait.