Marker-assisted recurrent selection for cumulating additive and interactive QTLs in recombinant inbred lines

A computer program has been designed to manage marker information in recomb inant inbred-line populations. The objective is to select pairs of inbred l ines (either recombinant-inbred or doubled-haploid) to be intercrossed, in order to accumulate all or most favourable alleles, either with additive ef fects or with interactive effects. The population size required to have a 9 5% chance of obtaining the best line from a given cross is computed, taking into account the number of QTLs and the probability that no recombination event occurs in any of the QTL confidence intervals. It is shown that the a ccuracy of QTL location greatly affects selection efficiency and that a rec urrent selection scheme is highly preferable for pyramiding many QTLs. An a pplication to the bread-making quality improvement of wheat is presented.