Mapping quantitative trait loci associated with chilling requirement, heat requirement and bloom date in peach (Prunus persica)

• Published in: The New phytologist 2010-03, Vol.185 (4), p.917-930
• Main Authors: Fan, Shenghua, Bielenberg, Douglas G., Zhebentyayeva, Tetyana N., Reighard, Gregory L., Okie, William R., Holland, Doron, Abbott, Albert G.
• Format: Article
• Language: English
• Subjects: Additives; bloom date; Blooms; Breeding; Chilling; Chilling requirement; Chills; Chromosome Mapping - methods; Cloning; Cold Temperature; Cooling; Crosses, Genetic; Cultivars; DNA sequences; endo-dormancy; Flowers - genetics; Flowers - physiology; Fruit trees; Gene mapping; Genomics; Genotypes; Geographical distribution; Heat; heat requirement; Horticulture; Hot Temperature; Inheritance Patterns - genetics; Linkage groups; Mapping; peach; peaches; Phenotype; Phenotypic traits; Plant breeding; Plant genetics; Plant species; Prunus - genetics; Prunus - physiology; Prunus persica; Quantitative trait loci; Quantitative Trait Loci - genetics; Quantitative Trait, Heritable; Seasons; Statistics, Nonparametric; Temperature requirements; Time Factors
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2009.03119.x

Chilling requirement, together with heat requirement, determines the bloom date, which has an impact on the climatic distribution of the genotypes of tree species. The molecular basis of floral bud chilling requirement is poorly understood, despite its importance to the adaptation and production of fruit trees. In addition, the genetic nature of heat requirement and the genetic interrelationships among chilling requirement, heat requirement and bloom date remain unclear. A peach (Prunus persica) F₂ population of 378 genotypes developed from two genotypes with contrasting chilling requirements was used for linkage map construction and quantitative trait loci (QTL) mapping. The floral bud chilling and heat requirements of each genotype were evaluated over 2 yr and the bloom date was scored over 4 yr. Twenty QTLs with additive effects were identified for three traits, including one major QTL for chilling requirement and two major QTLs for bloom date. The majority of QTLs colocalized with QTLs for other trait(s). In particular, one genomic region of 2 cM, pleiotropic for the three traits, overlapped with the sequenced peach EVG region. This first report on the QTL mapping of floral bud chilling requirement will facilitate marker-assisted breeding for low chilling requirement cultivars and the map-based cloning of genes controlling chilling requirement. The extensive colocalization of QTLs suggests that there may be one unified temperature sensing and action system regulating chilling requirement, heat requirement and bloom date together