Published online by Cambridge University Press: 27 March 2009
Random inbred lines produced by doubled haploidy and single seed descent have been used to estimate the number of genes or more correctly effective factors (k) controlling quantitative characters in barley. Estimates of k obtained by various biometrical methods are generally an underestimate since the effective factor may be considered a unit only in a temporary sense. In the past, estimates of k have been used to predict the range of inbreds extractable from a cross. Alternative and efficient methods are now available to predict the number of inbreds expected to exceed any given standard. Under these circumstances the need to estimate the number of genes is questionable.