Detection of moderate-effect QTLs for tree architectural traits in large avocado (Persea Americana) mapping populations

Abstract Avocado is a slow-maturing fruit crop, requiring costly management of tree architecture and canopy throughout the production season. Improving tree architecture can significantly lower avocado grove management costs, and genetic studies can play a key role in this. We analyzed two large F 1 segregating populations derived from reciprocal crosses between important avocado cultivars: ‘Simmonds’ (West Indian) and ‘Tonnage’ (Guatemalan). These populations were assessed for various tree architectural traits including plant height, trunk diameter and canopy size and volume. Genotyping was performed using single nucleotide polymorphism (SNP) markers from a 6 K Illumina SNP chip. Quantitative trait locus (QTL) analysis via GWAS models identified distinct genetic loci associated with the traits of interest. Notably, two QTLs for tree architecture traits were consistently observed on chromosomes 2 and 11, which offer preliminary insights into the genetic basis of these traits in avocado. These findings provide preliminary markers for future validation and potential use in molecular breeding to support avocado improvement efforts.