Use of Phenotypic and MAS Selection Based on Bulk Segregant Analysis to Reveal the Genetic Variability Induced by Artificial Hybridization in Apple

Abstract

Phenotypic selection in apple seedling populations (F1), derived from semidiallel hybridizations between genitors with different peculiarities (Florina and Liberty, resistant to apple scab attack; Starkrimson and Golden spur, with spur ideotype) was completed with Marker Assisted Selection (MAS), based on Bulk Segregant Analysis (BSA) technique. Molecular analyses performing by Bulk Segregant Analysis were intended to indentifying markers for scab resistance, powdery mildew resistance and architectural tree structure (ideotype) with bulks of five to six plants per groups, and testing the bulks with RAPD polymorphic primers. The polymorphic bands between the bulks were mostly associated to apple scab resistance genes. Concerning powdery mildew resistance and architectural tree structure analysis the results are inconclusive. Although it seems that the primer 54 showed a polymorphic band in a resistant to powdery mildew hybrid, which is missing in the sensitive hybrids, the result is only apparently favourable since this band is present in both parental forms (Starkrimson, tolerant to powdery mildew and Liberty, relative susceptible). Molecular profile of the standard ideotype and spur ideotype, resulted in hybrids originated in standard parental form (Florina) and spur parental form (Golden spur), were usually monomorphic. Genetic association among the parental molecular polymorphism for scab resistance and the other two important traits (powdery mildew resistance and ideotype), was not conclusive.