Genetic variability in apple fruit polyphenol composition in Malus × domestica and Malus sieversii germplasm grown in New Zealand.

Variations in the concentrations of flavan-3-ol, oligomeric procyanidin, chlorogenic acid, dihydrochalcone, flavonol, and anthocyanin polyphenol groups and total polyphenols were examined in the fruit peel and cortical flesh of 93 (80 Malus × domestica and 13 Malus sieversii) apple genotypes in at least 1 year between 2003 and 2005 grown at one site in New Zealand (NZ). Differences among genotypes accounted for 46-97% of the total variation in the concentrations of total polyphenols and each of the individual phenol groups in the flesh and peel in both species, whereas effects of year and genotype × year were minimal, except for peel flavonols in M. × domestica and flesh flavonols in both species. In these cases, differences among genotypes accounted for less than 30% of the total variation, which was less than the variation found for the interaction between genotype and year. Total polyphenol concentrations among genotypes were spread over a 7- and 9-fold range in the flesh and a 4- and 3-fold range in the peel of M. sieversii and M. × domestica, respectively, with the spread in concentrations of individual polyphenol groups in each tissue and within each species varying from a 2-fold to over a 500-fold range. Higher concentrations were generally found in M. sieversii. In M. × domestica, cultivars and breeding selections originating in NZ had lower average flesh and peel total polyphenols and chlorogenic acid than older cultivars previously imported into NZ from overseas countries.