Identification of molecular markers associated with the double flower trait in Petunia hybrida

The flower architectural trait of doubleness is a highly important breeding characteristic in the ornamental species petunia (Petunia hybrida). Here, we described the development of a near-isogenic line of a petunia population that segregated for single and double flower types. Sequence-related amplified polymorphism (SRAP) and simple sequence repeat (SSR) techniques, combined with bulked segregant analysis (BSA) were used to develop molecular markers linked to this floral trait. From a survey of 170 SRAP and 38 SSR primer combinations, one SRAP marker and one SSR marker were found to be linked to the target trait, each leading to the amplification of a specific band in double flower petunia. The two markers were verified in a population of 1065 plants, including 478 single flower and 587 double flower petunia individuals, and were shown to be tightly linked to the double flower locus with no recombination events observed. Hence, these markers have the potential for application in the positional analysis of the double flower locus and, ultimately, may contribute towards determining the genetic basis of flower type.