Construction of a Genetic Linkage Map and QTL Analysis for Frost Tolerance in Kernel Apricot (Armeniaca vulgaris x Armeniaca sibirica)

Early spring frost, an abiotic stress, poses a significant threat to kernel apricot (Armeniaca vulgaris x Armeniaca sibirica) production. Developing frost-tolerant cultivars of kernel apricot is crucial for preventing yield losses. To date, no quantitative trait loci (QTLs) associated with frost tolerance in kernel apricot have been reported. This study constructed a genetic linkage map of kernel apricot using an F1 population derived from a cross between 'Youyi', the maternal parent with high frost tolerance, and 'Longwangmao', the paternal parent with frost sensitivity. The map was based on sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) markers. The genetic map was constructed using 110 polymorphic markers, comprising 93 SRAP and 17 SSR markers. It consisted of 8 linkage groups covering a total of 884.30 cM with an average distance of 8.04 cM. A total of 98 progenies were genotyped and evaluated for frost tolerance. The F1 population exhibited significant variation in frost tolerance response. QTL analysis identified four loci contributing to frost tolerance on linkage groups 2, 3 and 6, accounting for 26.2%, 11.8% and 12.4%, respectively, of the total phenotypic variance explained. These findings provide insights into frost-tolerance QTLs and lay the foundation for marker-assisted breeding in kernel apricot genetic improvement for frost tolerance.