Mapping of Candidate Genes Involved in Bud Dormancy and Flowering Time in Sweet Cherry (Prunus avium)

The timing of flowering in perennial plants is crucial for their survival in temperate climates and is regulated by the duration of bud dormancy. Bud dormancy release and bud break depend on the perception of cumulative chilling during endodormancy and heat during the bud development. The objectives of this work were to identify candidate genes involved in dormancy and flowering processes in sweet cherry, their mapping in two mapping progenies 'Regina' × 'Garnet' and 'Regina' × 'Lapins', and to select those candidate genes which co-localized with quantitative trait loci (QTLs) associated with temperature requirements for bud dormancy release and flowering. Based on available data on flowering processes in various species, a list of 79 candidate genes was established. The peach and sweet cherry orthologs were identified and primers were designed to amplify sweet cherry candidate gene fragments. Based on the amplified sequences of the three parents of the mapping progenies, SNPs segregations in the progenies were identified. Thirty five candidate genes were genetically mapped in at least one of the two progenies and all were in silico mapped. Co-localization between candidate genes and QTLs associated with temperature requirements and flowering date were identified for the first time in sweet cherry. The allelic composition of the candidate genes located in the major QTL for heat requirements and flowering date located on linkage group 4 have a significant effect on these two traits indicating their potential use for breeding programs in sweet cherry to select new varieties adapted to putative future climatic conditions

Mapping of Candidate Genes Involved in Bud Dormancy and Flowering Time in Sweet Cherry (Prunus avium).

The timing of flowering in perennial plants is crucial for their survival in temperate climates and is regulated by the duration of bud dormancy. Bud dormancy release and bud break depend on the perception of cumulative chilling during endodormancy and heat during the bud development. The objectives of this work were to identify candidate genes involved in dormancy and flowering processes in sweet cherry, their mapping in two mapping progenies 'Regina' × 'Garnet' and 'Regina' × 'Lapins', and to select those candidate genes which co-localized with quantitative trait loci (QTLs) associated with temperature requirements for bud dormancy release and flowering. Based on available data on flowering processes in various species, a list of 79 candidate genes was established. The peach and sweet cherry orthologs were identified and primers were designed to amplify sweet cherry candidate gene fragments. Based on the amplified sequences of the three parents of the mapping progenies, SNPs segregations in the progenies were identified. Thirty five candidate genes were genetically mapped in at least one of the two progenies and all were in silico mapped. Co-localization between candidate genes and QTLs associated with temperature requirements and flowering date were identified for the first time in sweet cherry. The allelic composition of the candidate genes located in the major QTL for heat requirements and flowering date located on linkage group 4 have a significant effect on these two traits indicating their potential use for breeding programs in sweet cherry to select new varieties adapted to putative future climatic conditions

Cherry Breeding: Sweet Cherry (Prunus avium L.) and Sour Cherry (Prunus cerasus L.)

none3noThis chapter describes the cherry’s origins, botanical classification (taxonomy) and domestication of the only two species cultivated for food and industrial processing: sweet and sour cherry. Cherry breeding programs worldwide have focused on trees, fruit quality traits and resistance to biotic and abiotic factors as well as on specific local characteristics. A detailed discussion of breeding techniques (crossbreeding, early selection, seedling screening and field assessment, embryo culture and mutagenesis) follows. A section is dedicated to sour cherry breeding, whose problems differ from those of the sweet cherry. We underline the importance of the knowledge and conservation of genetic resources for their use in genomic approaches. Then, discuss breeding strategies and the new traits that have been introduced in new genotypes through genomics. Germplasm biodiversity is analyzed in its phylogenetic context. Then, the molecular breeding approaches are extensively described with particular attention for gene mapping and the development of marker linked to monogenic and polygenic traits. A section is dedicated to the gametophytic incompatibility of the sweet cherry, with an updated summary of the research conducted to identify the 57 incompatibility groups (the cultivars for each of these are reported). Finally, we take into account other aspects related to breeding in respect to how functional genes affect some fruit characteristics, the strategies used after the cherry genome was sequenced and the potential of genetic engineering. The Appendix provides pomological profiles of 44 of the most important innovative cultivars, according to the descriptive standard of the Brooks and Olmo official lists with each accompanied by original photos to aid in their identification.noneDondini, Luca; Lugli, Stefano; Sansavini, SilvieroDondini, Luca; Lugli, Stefano; Sansavini, Silvier

A fruit firmness QTL identified on linkage group 4 in sweet cherry (<em>Prunus avium</em> L.) is associated with domesticated and bred germplasm.

Fruit firmness is an important market driven trait in sweet cherry (Prunus avium L.) where the desirable increase in fruit firmness is associated with landrace and bred cultivars. The aim of this work was to investigate the genetic basis of fruit firmness using plant materials that include wild cherry (syn. mazzard), landrace and bred sweet cherry germplasm. A major QTL for fruit firmness, named qP-FF4.1, that had not previously been reported, was identified in three sweet cherry populations. Thirteen haplotypes (alleles) associated with either soft or firm fruit were identified for qP-FF4.1 in the sweet cherry germplasm, and the "soft" alleles were dominant over the "firm" alleles. The finding that sweet cherry individuals that are homozygous for the "soft" alleles for qP-FF4.1 are exclusively mazzards and that the vast majority of the bred cultivars are homozygous for "firm" alleles suggests that this locus is a signature of selection. Candidate genes related to plant cell wall modification and various plant hormone signaling pathways were identified, with an expansin gene being the most promising candidate. These results advance our understanding of the genetic basis of fruit firmness and will help to enable the use of DNA informed breeding for this trait in sweet cherry breeding programs