Degree Type

Dissertation

Date of Award

1988

Degree Name

Doctor of Philosophy

Department

Agronomy

First Advisor

Walter R. Fehr

Abstract

Developing a nutrient solution system for evaluating the iron (Fe)-efficiency of soybean (Glycine max (L.) Merr.) genotypes would be beneficial to breeders interested in developing superior cultivars. The objectives of this research were to evaluate alternative nutrient solution techniques for the evaluation of lines with a wide range of Fe efficiency and to determine the effectiveness of nutrient solution evaluation in a recurrent selection program for Fe efficiency;Evaluation of lines for Fe-efficiency was conducted on calcareous soil in the field and in nutrient solution in a greenhouse. Eight genotypes with a wide range of Fe efficiency were evaluated in 15 nutrient solution treatments consisting of a factorial arrangement of five bicarbonate levels and three solution change schedules. The parents of the Cycle 0 to 7 populations of AP9 were evaluated in three nutrient solutions differing in bicarbonate concentration. One hundred random lines of the Cycle 6 and Cycle 7 populations of AP9 were evaluated in nutrient solution containing a high bicarbonate concentration;Replacing the solution every fourth-day was not superior to replacing it only at each stage of plant development, or not changing the solution throughout the test. A stepwise increase in bicarbonate level at each stage of plant development was not superior to utilizing a constant level of bicarbonate throughout the test;The rates of genetic gain for Fe efficiency in Cycles 0 to 7 were similar for nutrient solution and field tests. The estimated heritability of Fe efficiency on a plot basis was 22 ± 7% for nutrient solution and 10 ± 2% for field tests. Using a 10% selection intensity, actual genetic gain was -0.05 score for nutrient solution and -0.08 score for field tests when compared with a common field standard. Actual genetic gain was -0.14 score for nutrient solution and -0.11 score for field tests when compared with a common nutrient solution standard. Nutrient solution evaluation can be used effectively in a recurrent selection program for improved Fe efficiency.

DOI

https://doi.org/10.31274/rtd-180813-11241

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Michael Barry Dragonuk

Language

en

Proquest ID

AAI8825389

File Format

application/pdf

File Size

115 pages

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