Family and line selection far seed yield of soybean

Plant-row-yield tests (PRYT) are used by soybean [Glycine max (L.) Merr.] b reeders for the initial evaluation of experimental lines. The highest yield ing lines in the PRYT are advanced for additional testing in replicated tes ts. The objective of this study was to determine the, reliability of select ion for seed yield in unreplicated plots by the family and line methods of selection. Four F-3-derived lines from each of 21 F-2 families from four po pulations were grown in a PRYT during 1995 and in replicated tests at four environments in 1996. For the family method the mean seed yield of the four S-derived lines of each Fz family was used to identify superior families f rom which to select individual lines. For the line method,lines were select ed without regard to the family structure. The seed yield of the selected a nd unselected lines on the basis of data from the PRYT was compared with th eir mean seed yield in the 1996 environments. The total number of lines sel ected by the family method was less than for the line method in ah populati ons, The percentage of selected lines that were correctly classified was si milar far bot ii met beds. There was a greater percentage of lines incorrec tly rejected by the family method than by the line method. The use, of repl ication at an individual location did not improve the selection of lines by the family or line methods of selection. For the selection of lines for se ed yield in unreplicated plots, breeding methods that rely on family perfor mance would not be more effective or efficient than methods that ignore fam ily structure. To obtain lines for yield tests at multiple locations, selec tion of Lines by the line method an the basis of their performance in a PRY T would be better than the use of random lines.