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Title:Evaluation of Soil Compaction, Plant Density, and Resistance to Phytophthora Root Rot in Soybeans
Author(s):Moots, Craig Keith
Department / Program:Agronomy
Discipline:Agronomy
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Agriculture, Agronomy
Abstract:Phytophthora root rot, caused by Phytophthora megasperma f. sp. glycinea Kuan and Erwin, is a soil-borne fungal disease of soybean Glycine max (L.) Merr. . Studies were conducted to determine the effects of soil compaction on phytophthora incidence, to determine if reduced soybean stand due to phytophthora is the only factor responsible for yield reduction, and to study the inheritance of resistance to phytophthora in the plant introduction (PI) 92718-2.
Field studies conducted for two years found that soil compaction significantly increased incidence of phytophthora. Increased disease incidence due to soil compaction helped differentiate susceptible from resistant cultivars. Soil compaction may be useful in field evaluations to aid in identifying susceptible soybean lines.
Comparisons of the phytophthora susceptible cultivar 'Corsoy' and artificial removal of plants in the resistant isoline L27 indicated factors other than stand reduction contributed to yield reduction in two of the three environments tested. In the third environment, which had the lowest disease incidence, stand reduction was the most critical factor influencing yield reduction from phytophthora.
Inheritance studies involving PI 92718-2 found three genes controlling resistance to phytophthora physiologic races 1, 2, and 3; two genes for races 4, 6, and 8; and a single gene controlling resistance to races 5, 7, 9, and 16 in PI 92718-2. Phytophthora resistance genes in PI 92718-2 were found allelic to Rps(,1), Rps(,4), and Rps(,6). Information gained on the inheritance of resistance and allelic relationships of resistance genes in PI 92718-2 will aid in its use as a source of phytophthora resistance.
Issue Date:1985
Type:Text
Description:85 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.
URI:http://hdl.handle.net/2142/71610
Other Identifier(s):(UMI)AAI8521840
Date Available in IDEALS:2014-12-16
Date Deposited:1985


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