Date of Award
Doctor of Philosophy
Fifty random soybean Glycine max (L.) Merrill lines of maturity group II from intermated populations were used to compare hill and row plot arrangements for selection of superior genotypes for yield, maturity, height, lodging, and phenotypic score. Single, nonbordered hill plots spaced 102 x 102 cm were grown in random and nonrandom complete block designs. The row arrangement was a two-row, nonbordered plot with 69 cm between rows within the plot and 102 cm betwen plots. S(,6) progeny from 50 S(,3) plants were evaluated in hill plots at eight environments and in row plots at 10 environments in Iowa during 1977 and 1978;There was no difference in the effectiveness of selection for yield between random and nonrandom hills. The hill and row plots were equally effective in selecting the top two lines. Actual genetic gain was 2.5 q/ha for random hills, 2.8 q/ha for nonrandom hills, and 3.0 q/ha for rows when the top five lines were considered. Predicted genetic gain per year was 0.64 q/ha for both hill arrangements compared with 0.41 q/ha for rows;Selection for maturity, height, lodging, and phenotypic score was similar in effectiveness for the three plot arrangements. Genotypic correlations of line performance between random and nonrandom hills were nearly perfect and between hills and rows ranged from 0.89 to 0.99 for the four traits;The primary advantage of hills is the reduction in number of years for cultivar development by eliminating the need for a generation of seed increase before yield evaluation in row plots. The use of progeny rows for visual selection and for a seed increase can be replaced by combining visual selection and yield evaluation in replicated hill plots. In environments where intergenotypic competition between single, nonbordered hills is minimal, selection for superior agronomic genotypes can be conducted effectively and efficiently in nonrandom hill plots.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Marshall L. Garland
Garland, Marshall L., "Selection for agronomic traits in hill and row plots of soybeans " (1980). Retrospective Theses and Dissertations. 6725.