Genetic analysis of quantitative variation in almond nut traits

In almond (Prunus dulcis L.), the physical characteristics of nuts and kernels underpin both crop yield and processing quality. In this research, the objective was to investigate whether quantitative trait locus (QTL) mapping could identify genomic regions that affect nut and kernel traits in the almond varieties Nonpareil and Lauranne and to investigate whether these regions have effects in two other almond populations (Nonpareil × Constantí and Nonpareil × Tarraco). Linkage mapping and QTL analysis were carried out using single-nucleotide polymorphisms (SNPs) that had previously been discovered using a set of 180 Nonpareil × Lauranne F₁ progeny. With the Nonpareil × Lauranne population, QTLs were detected in ten regions on the Nonpareil map and 16 regions on the Lauranne map. Each Nonpareil QTL region and most Lauranne QTL regions were also detected using the Constantí and/or Tarraco populations. Most QTLs had small effects, indicating that the traits investigated here may be more suitable for genomic selection than for marker-assisted selection. With anchoring of QTL regions to genome sequence assemblies for Nonpareil and Lauranne, some candidate genes were identified that could be evaluated in future research.