EXPLORING THE GENETICS OF AROMA PRODUCTION IN APPLES

Abstract

Apple aroma is a major determinant of consumer acceptability. In order to better understand the aroma of apples, gas-chromatography mass-spectrometry (GCMS) was used to quantify apple volatiles across 515 apple varieties from Canada’s Apple Biodiversity Collection (ABC). Among the volatiles identified, esters and aldehydes were the most abundant classes of compounds with butyl acetate and hexyl acetate present in nearly every variety. Using principal component analysis (PCA), It was determined that the primary axis of variation of the apple volatilome is correlated with harvest date: early-harvested apples tend to express larger numbers and higher amounts of volatiles than late-harvested apples. Through genome-wide association studies (GWAS) with 250,579 single nucleotide polymorphisms (SNPs) I identified a significant association between SNPs at a NAC18.1 transcription factor and the abundances of two key volatile compounds: 1-hexanol and 1-butanol. Taken together, these results provide a foundation for understanding the genetic basis of apple aroma production.