Methods for estimating gene numbers for quantitative characters using doubled haploid lines.

Three methods of estimating the numbers of genes segregating for quantitative characters using doubled haploid lines are presented. The first uses estimates of the range and genetical variance of an F1 or F2 derived population. The second adapts the genotype assay method of Jinks and Towey (1976) to F2 derived lines. The third uses the variances of an F2 derived population. Statistical problems of obtaining meaningful estimates using these methods are discussed and it is concluded that genotype assay is the best method for distinguishing between few and many genes. These methods are illustrated using data from an experiment containing doubled haploid lines of barley developed using the H. bulbosum system.