Degree Type


Date of Award


Degree Name

Doctor of Philosophy




Broadening the genetic base of the cultivated soybean Glycine max (L.) Merr. by use of the wild progenitor, Glycine soja Sieb. & Zucc., may reduce vulnerability to pests and increase the genetic potential of cultivars for seed yield. The objective of this study was to evaluate yield and other agronomic characteristics of soybean lines derived from populations with different percentages of G. soja parentage. Two G. soja accessions were crossed to one of two high-yielding G. max cultivars followed by five backcrosses to the G. max parent. F(,2) plants lacking hardseededness, vininess, and shattering, and having maturity similar to the G. max parent were identified from the backcross but not from the single-cross populations. Progeny of selected plants from the populations were compared to the recurrent parents for seed yield, maturity, lodging, and height in four environments during two years;Significant variation was observed among lines in each backcross generation for the four traits. Mean yields and lodging scores of the populations improved from the BC(,1) to the BC(,4) generation. No lines from the BC(,1) generation performed as well as the recurrent parent for all traits. Three backcrosses to the cultivated parent were necessary to obtain a reasonable number of lines similar to the recurrent parent. No enhancement in yield was obtained from the introgression of G. soja germplasm into the two soybean cultivars.



Digital Repository @ Iowa State University,

Copyright Owner

David Stanley Ertl



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88 pages