SOYBEAN-SEED YIELD RESPONSE IN ROW-PLOTS AND HILL-PLOTS UNDER A RECURRENT SELECTION PROGRAM

The objective of this study was to evaluate F-4 lines in both row- and hill-plots for agronomic traits in order to test the effectiveness of selecting high-yielding S-1 soyabean (Glycine max (L.) Merr.) lines s elected in hill-plots after two cycles of recurrent selection. There w as a cumulative seed yield loss of 197 kg/ha from cycle C-0 to C-2 whe n the selections were evaluated in row-plots but a cumulative gain in seed yield of 533 kg/ha from C-0 to C-2 was observed when the selectio ns were evaluated in hill-plots. Ranking of seed yield between row- an d hill-plots showed a nonsignificant association, but correlation coef ficients between the two methods of testing were positive and highly s ignificant for height, lodging and maturity. Thus, evaluation of heigh t, lodging and maturity can be carried out effectively with either met hod of planting. There were increases in plant height, in lodging scor es and in days to maturity with each cycle of selection. These changes were evident in both row and hill-plots. The lack of seed yield respo nse to selection as measured in row-plots and a non-significant associ ation between the two plot arrangements indicated that seed yield eval uation by S-1 testing in hill-plots was nor a reliable procedure in th e identification of productive genotypes.