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Title:Evaluation of Soybean Genotypes in Monoculture and Multiple Cropping Systems
Author(s):Mcbroom, Roger Lynn
Department / Program:Agronomy
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Agronomy
Abstract:Samples of currently grown soybean (Glycine max (L.) Merrill) cultivars, near isogenic lines of soybeans, and soybean plant introductions were planted in two cropping systems--monoculture and relay intercropping with small grains, in five experiments at Urbana and DeKalb, Illinois during 1978 and 1979. The objectives of this study were to (a) determine which current soybean cultivars perform best in a relay intercropping system, (b) determine if certain morphological and maturity characteristics (controlled by the genes, dt(,1), Dt(,2), Lf(,1), ln and e(,3) confer an advantage in a relay intercropping system, and (c) determine if there is a genotype x cropping system interaction that would require separate breeding programs for maximum progress in developing new cultivars for use in these different systems.
There was a consistent lack of a significant genotype x cropping system interaction when soybeans were interplanted in small grains {oats (Avena sativa L.) or wheat (Triticum aestivum L.)} and planted in monoculture on the same day. Apparently the early season competition in intercropping was not sufficient in these experiments to cause differential reactions among these genotypes. Apparently early generations of a breeding program could be grown and selected in monoculture. Only advanced generations would need to be tested in relay intercropping.
A good full season soybean cultivar for a specific location seems to be the proper choice for a relay intercropping system at the same location. Further performance testing in relay intercropping should concentrate on group III cultivars, at Urbana and group II cultivars at DeKalb. Modification of morphological and maturity characteristics did not increase yields in relay intercropping, double cropping, or monoculture.
Fourteen soybean cultivars were planted with a no-till planter following wheat harvest at Urbana on 7 July 1978 and 7 July 1979. Twelve of these soybean cultivars were no-till planted at Brownstown, Illinois in 1979. Twelve near isogenic lines of soybeans were planted in a conventional seedbed following wheat harvest at Urbana in 1978 and 1979 and at Brownstown in 1979. Objectives of this study were to evaluate current soybean cultivars in double cropping environments and to determine if morphological or maturity characteristics would be of an advantage in double cropping environments.
'Wells' and 'Cutler 71' were significantly lower yielding at Urbana and probably should not be recommended for double cropping at locations near Urbana. 'Corsoy', 'Harcor', 'Cumberland', and 'Williams' produced good yields in double cropping environments. Continued testing of group II and group III cultivars in double cropping environments at Urbana is recommended.
Relay intercropped soybeans and wheat returned the highest net income per unit area of land at Urbana in 1979, followed by double cropped soybeans and wheat. Monoculture soybeans returned the highest net income per unit area of land at DeKalb in 1979, followed by relay intercropped soybeans and wheat. Future research on relay intercropping should be concentrated on the soybean-wheat combination rather than the soybean-oat combination because of economic considerations.
Issue Date:1980
Description:83 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.
Other Identifier(s):(UMI)AAI8108601
Date Available in IDEALS:2014-12-14
Date Deposited:1980

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