TY - BOOK

T1 - Breeding Potential in Danish Apple Cultivars

T2 - Genetic diversity of and Genome-Wide Association Mapping of Fruit Quality Traits

AU - Larsen, Bjarne

PY - 2016

Y1 - 2016

N2 - The diversity in plant genetic resources is a prerequisite for genetic improvement of cultivatedcrop species. Lack of in-depth characterization and evaluation of gene bank accessions is amajor obstacle for their potential utilization. The Danish apple (Malus domestica L.) genebank collection represents an ensemble of cultivars that have never previously been geneticallyaccessed. The aim of this thesis is to study the genetic structure, affiliation and overall diversitywhich should facilitate future conservation management strategies. It may also contributewith new knowledge for better understanding of the link between phenotypes and theunderlying gene-tic background which is crucial in plant breeding. We found a considerablegenetic diversity in the collection and no genetic structure. We exposed a high number of accessionsin admix and revealed several putative cultivar parentages, never previously reported.Unique fingerprints were obtained for all accessions except for distinctive subclonal sportsand synonym accessions. The cultivar ensemble was shown to hold 22% triploid accessions.We developed a new protocol for genotyping S-RNase alleles in apple and revealed 25 differentalleles, including several rare alleles. Using historical gene bank records, including aromavolatile analysis, sugar and acid data and other fruit- and tree character records, we establishedgenotype-phenotype relationships, performing a genome-wide association study. Anumber of SNP markers are presented that can be used directly for marker-assisted selection.In addition, we suggest a number of candidate genes involved in the control of several importantfruit quality traits. Future studies and breeding attempts can therefore benefit from theresults, including genetic fingerprints and pedigree reconstruction. In addition, several of theSNP markers presented can be used directly in selection for specific traits in breeding lines.However, further characterization and evaluation of additional important horticultural traitsare still needed for upmost utilization of the apple gene bank collection.

AB - The diversity in plant genetic resources is a prerequisite for genetic improvement of cultivatedcrop species. Lack of in-depth characterization and evaluation of gene bank accessions is amajor obstacle for their potential utilization. The Danish apple (Malus domestica L.) genebank collection represents an ensemble of cultivars that have never previously been geneticallyaccessed. The aim of this thesis is to study the genetic structure, affiliation and overall diversitywhich should facilitate future conservation management strategies. It may also contributewith new knowledge for better understanding of the link between phenotypes and theunderlying gene-tic background which is crucial in plant breeding. We found a considerablegenetic diversity in the collection and no genetic structure. We exposed a high number of accessionsin admix and revealed several putative cultivar parentages, never previously reported.Unique fingerprints were obtained for all accessions except for distinctive subclonal sportsand synonym accessions. The cultivar ensemble was shown to hold 22% triploid accessions.We developed a new protocol for genotyping S-RNase alleles in apple and revealed 25 differentalleles, including several rare alleles. Using historical gene bank records, including aromavolatile analysis, sugar and acid data and other fruit- and tree character records, we establishedgenotype-phenotype relationships, performing a genome-wide association study. Anumber of SNP markers are presented that can be used directly for marker-assisted selection.In addition, we suggest a number of candidate genes involved in the control of several importantfruit quality traits. Future studies and breeding attempts can therefore benefit from theresults, including genetic fingerprints and pedigree reconstruction. In addition, several of theSNP markers presented can be used directly in selection for specific traits in breeding lines.However, further characterization and evaluation of additional important horticultural traitsare still needed for upmost utilization of the apple gene bank collection.

UR - https://soeg.kb.dk/permalink/45KBDK_KGL/fbp0ps/alma99122096800205763

M3 - Ph.D. thesis

BT - Breeding Potential in Danish Apple Cultivars

PB - Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen

ER -