Conditions favouring doubled haploid breeding over conventional breeding of self-fertilizing crops

Summary Monte Carlo computer simulation was used to investigate the conditions favouring doubled haploid breeding over conventional breeding of self-fertilizing crops. Two different systems of doubled haploid breeding and three systems of conventional breeding were compared for two criterion parameters, i.e., the probability of obtaining desirable genotypes and the expected genetic advance of selected lines. It was inferred that the efficiency of production of haploid and doubled haploid plants primarily determines the success of the doubled haploid breeding method. In doubled haploid breeding, about 1/5, hopefully 1/2 as many test plants need to be raised as in conventional breeding to achieve the same level of success. With this condition begin satisfied, the doubled haploid breeding method can efficiently be used when one or more of the following conditions are met: (i) a relatively small number of loci, presumably ten of less, is involved with the breeding objective concerned, (ii) desirable alleles are recessive to undesirable ones at most, if not all, of the segregating loci, and (iii) the genes are not strongly linked. It was confirmed that the doubling of haploids can better be applied to selected F₂ plants rather than to F₁ plants.