Development of sequence-tagged site markers linked to the pillar growth type in peach (Prunus persica)

In peach [Prunus persica (L.) Batsch], trees showing columnar (also termed pillar or broomy) growth habit are of interest for high-density production systems. While the selection of the pillar homozygous phenotype (brbr) can be carried out prior to field planting, the intermediate heterozygous upright phenotype is difficult to distinguish from standard trees until they are quite large in the field. Application of marker-assisted selection would be helpful in establishing more efficient breeding programmes developing pillar and upright varieties. Thirty-four amplified fragment length polymorphism (AFLP) markers and three simple sequence repeat (SSR) markers identified by bulked segregant analyses mapped together with the br gene on linkage group 2 (LG 2) of the Prunus reference map. The linkage group covers 92.9 cM. The AFLP marker ETGM61_291R mapped with 4.8 cM to the br gene on one side and the closest AFLP markers ETAM56_267A, ECAM61_426A and ETAM48_279A with 3.8 cM on the other side. These four AFLP markers were sequenced, and two, ETGM61_291R and ETAM48_279A, were successfully converted into sequence-tagged site (STS) markers for marker-assisted selection. BLAST searches against the peach genome placed the br gene in the region 17-18 Mb on LG 2.