Evaluation of the Pure‐line Family Method for Cultivar Development1

Abstract

The pure‐line family method (PLF) has been proposed as a means of developing high yielding cultivars. The method consists of harvesting individual F2 plants from a population and selling the bulk progeny of each plant (family) to a desired level of homozygosity. individual plant (pure line) is harvested from each family, and yield tested in replicated trials. If a line has superior performance, additional plants from the F2 family are evaluated as potential cultivars.Two soybean [Glycine max (L.) Merr.] populations were used to compare the PLF method with three alternative methods used by soybean breeders, early‐generation testing of bulk progeny from F2 plants (BF), pedigree selection (PS), and single‐seed descent (SSD). derived lines developed by each method were compared for yield during 2 years. The BF method was superior to PLF for identifying the top F2 families, but the number of superior F5 lines selected was similar. The PLF method produced a greater number of superior pure lines than did PS or SSD. Yield of the top line was not different for the four methods.The choice between PLF and BF would depend on the resources available and the breeding objective. The PLF method generally would be a faster method for cultivar development than BF, but BF would be preferred when recurrent selection by early‐generatlon testing was feasible for improving a character. Cultivar development with PLF would be faster than with PS when winter facilities were available for generation advance. The PLF method may provide a larger number of superior F5 lines than SSD; however, it would sample less genetic variability and require more years, land, labor, and record keeping than SSD.