A genetic linkage map of Phalaenopsis-based on AFLP markers and the "two-way pseudo-testcross" mapping strategy

Abstract

Phalaenopsis are grown widely as cut-flowers and potted plants in the floriculture trade. Here, we report the genetic linkage maps for Phalaenopsis, which were developed by genotyping 88 F1 progenies from a cross between Phalaenopsis '462' (male) and Phalaenopsis '20' (female) with amplification fragment length polymorphisms (AFLP) in a "two-way pseudo-testcross" mapping strategy. For a total of 416 polymorphic loci showing Mendelian segregation were generated from 71 AFLP primer combinations. The data were analyzed using JoinMap 3.0 to construct the parent-specific linkage maps. The paternal map consisted of 15 linkage groups and 122 AFLP makers, covering 820.3 cM with a mean distance of 6.7 cM between adjacent markers. The maternal map consisted of 14 linkage groups with 175 loci, resulting in a total genetic distance of 878.3 cM and an average genetic distance of 5.0 cM between adjacent markers. Yet, as far as we know, this is the first study to construct the linkage map of Phalaenopsis. The two maps will serve as the frameworks for mapping of horticultural quantitative trait locis (QTLs) and furnish reference information for the application of future marker-assisted selection in Phalaenopsis breeding.