Genetic map of the primocane-fruiting and thornless traits of tetraploid blackberry

• Published in: Theoretical and applied genetics Vol. 126; no. 10; pp. 2521 - 2532
• Main Authors: Castro, P, Stafne, E. T, Clark, J. R, Lewers, K. S
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.10.2013; Springer Berlin Heidelberg; Springer; Springer Nature B.V
• Subjects: Agriculture; Biochemistry; Biomedical and Life Sciences; Biotechnology; Blackberries; Chromosome Mapping; chromosome number; Chromosome Segregation - genetics; Chromosomes; Chromosomes, Plant - genetics; Crosses, Genetic; Cultivars; Development; Fruit - genetics; fruiting; Fruits; Genetic aspects; Genetic Linkage; Genetic Markers; genotype; Growth; Horticulture; Life Sciences; linkage groups; loci; marker-assisted selection; microsatellite repeats; Microsatellite Repeats - genetics; Morphology; Original Paper; Phenotype; Physiological aspects; Plant Biochemistry; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant Stems - genetics; Plants; Polymorphism, Genetic; Polyploidy; primocanes; progeny; Quantitative genetics; Quantitative Trait, Heritable; Rosaceae - genetics; seedlings; Tetraploidy; thornless varieties; Spain; United States > US; Dominant Marker; Linkage Phase; Linkage Group; Homologous Chromosome; Double Reduction
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-013-2152-3

Blackberry primocane fruiting, fruiting on first-year canes, has the potential to expand blackberry production both seasonally and geographically. The incorporation of the primocane-fruiting trait into cultivars with desirable horticultural attributes is challenging due to its recessive nature and tetrasomic inheritance. Molecular marker-assisted selection has high potential to facilitate incorporation, because breeders already use morphological marker-assisted selection of seedlings without marginal cotyledonary hairs to identify progeny that will be thornless when mature. The development of a genetic linkage map with these two traits is the first step to utilizing molecular markers in breeding for thornless primocane-fruiting blackberry cultivars. A full-sib family segregating for thornlessness and primocane fruiting, from a cross between ‘APF-12’ and ‘Arapaho’, was used to construct the first genetic map of tetraploid blackberry. Segregation patterns of several dominant markers and the two phenotypic traits fit those expected uniquely with tetrasomic inheritance (e.g., 5:1, 11:1 and 35:1). Some loci showed significant double reduction frequencies, but genotypes that could have originated only from double reduction were not found. The map consists of seven linkage groups (LG) in each parent, consistent with the basic number of chromosomes (2n = 4x = 28). Naming of LG1-LG6 followed that of the recently revised system for raspberry using SSR markers in common between blackberry and raspberry, and LG7 was tentatively defined by default. The loci controlling primocane fruiting and thornlessness were not linked to each other; thornless/thorny, the S Locus, was mapped on LG4, and the primocane-/floricane-fruiting locus, named in this work the F Locus, on LG7.