To develop inbred lines, parents are crossed to generate segregating populations from which superior inbred progeny are selected. The value of a particular cross thus depends on the expected performance of its best progeny, which we call the superior progeny value. Superior progeny value is a linear combination of the mean of the cross's progeny and their standard deviation. In this study we specify theory to predict a cross's progeny standard deviation from QTL results and explore analytically and by simulation the variance of that standard deviation under different genetic models. We then study the impact of different QTL analysis methods on the prediction accuracy of a cross's superior progeny value. We show that including all markers, rather than only markers with significant effects, improves the prediction. Methods that account for the uncertainty of the QTL analysis by integrating over the posterior distributions of effect estimates also produce better predictions than methods that retain only point estimates from the QTL analysis. The utility of including estimates of a cross's among-progeny standard deviation in the prediction increases with increasing heritability and marker density but decreasing genome size and QTL number. This utility is also higher if crosses are envisioned only among the best parents rather than among all parents. Nevertheless, we show that among crosses the variance of progeny means is generally much greater than the variance of progeny standard deviations, restricting the utility of estimates of progeny standard deviations to a relatively small parameter space. I N inbred line development, parents are crossed to generate segregating populations from which superior inbred progeny are selected. The value of a particular cross depends on the performance of its best progeny rather than on its mean progeny performance. In a typical breeding program, far too many crosses are possible between elite candidate parents for exhaustive evaluation. For example, among 50 elite parents there are 1225 possible crosses. Even if it were feasible to evaluate a sufficient set of progeny from all those crosses, it is unlikely that that would be efficient. Rather, one would want to predict, among possible crosses, which ones are most likely to lead to superior inbred lines.Schnell and Utz (1975) introduced the usefulness concept for line development. Their definition of the usefulness of the cross m was U m ¼ m m 1 DG m ¼ m m 1 is GðmÞ h m , where m m is the population mean of homozygous lines that can be derived from cross m, s 2 GðmÞ is the genetic variance among these lines, h m is the square root of the heritability, and i is the standardized selection intensity. Two other criteria for similar usefulness are the varietal ability (Wright 1974;Gallais 1979) and the probability of obtaining transgressive segregants ( Jinks and Pooni 1976). Here, rather than focus on the genetic gain that might be obtained within a cross, we sought a simpler characterization that expresses which crosses would...