Interval Mapping of Quantitative Trait Loci Underlying Endosperm Traits with NCIII and TTC Designs

According to quantitative genetic models for triploid endosperm traits, a new mapping approach was proposed based on North Carolina Design III (NCIII) and Triple Test Cross (TTC). Feasibility and efficacy of the method were investigated through simulated data. Experimental factors considered in the simulations included QTL heritability, number of plants in F2 population, and number of endosperms collected per family. The results suggested that the 2 methods had satisfactorily high detection powers, which reached 100% even when the QTL heritability was 5%. The TTC-based approach tended to have slightly higher power than the NCIII-based one. Both approaches could distinguish 2 dominance effects successfully. In general, the TTC-based approach could offer better estimations of either QTL position or effect, though this superiority waned as the heritability and sample size increase.