Marker-assisted breeding (MAB) on apple and pear and new approaches for QTLs and major gene genotyping involved in disease resistance

XXXI International Horticultural Congress (IHC2022): International Symposium on Breeding and Effective Use of Biotechnology and Molecular Tools in Horticultural Crops, 14-20 August 2022, Angers, France.

Apple and pear breeding is a long process that can take more than 20 years. Considering the future challenges of fruit tree growing in a climate change scenario (high fruit quality and regular production), improving breeding program efficiency is essential. A good strategy to increase breeding program efficiency is the development of SNP-type molecular markers and their application in marker-assisted breeding (MAB). Several tools such as the Illumina 20K chip and the Affymetrix-Axiom 480K (apple-fruit) and 70K (pear) chips have been developed to map SNP markers on the respective genomes. However, the practical use of molecular markers by breeders is still disconnected from academic knowledge. To overcome this gap, we selected several SNP-type molecular markers in apple and pear, and assayed and validated them in apple and pear breeding programs. After an evaluation of their benefits and limitations, they were applied in the progenitor and elite genotype selections to increase the efficiency of the breeding process. To do so, published SNP-type molecular markers associated with major genes in apple and developed new markers linked to QTLs involved in disease resistance in pear were assayed and validated. This set of validated molecular markers is now routinely applied as MAB in our breeding programs. In this paper, we present two different methodologies for searching and validating SNP-type molecular markers, discuss the uses and limitations of these markers within apple and pear breeding programs and propose some strategies to improve their breeding efficiency.

Peer reviewed