|Campbell, Benjamin - Todd|
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/2005
Publication Date: 9/23/2005
Citation: Campbell, B.T., Jones, M.A. 2005. Assessment of genotype environment interactions for yield and fiber quality in cotton performance trials. Euphytica. 144(1-2):69-78. Interpretive Summary: Plant breeding programs routinely practice selection for genotypes that display stability for a trait or set of traits across testing environments. Prior to selecting stable genotypes for a trait or set of traits, proper testing locations must be identified that best represent the target crop growing regions the breeding program is directed toward. The objectives of this study were to dissect genotype x environment interactions (the basis for genotype stability) for agronomic performance and fiber quality present in cotton performance trials conducted in twelve location-year environments in South Carolina, and to identify testing locations that best represent different target cotton production regions within the state. For lint yield, genotype x environment interactions were larger in higher yielding environments indicating that selection of high yielding genotypes may result in selection for lower yield stability across environments. For fiber strength, genotypes with lower average fiber strength values displayed larger genotype x environment interactions, indicating that selection for high fiber strength should not result in lower fiber strength stability across environments. The five testing locations evaluated in this study from 2000-2003 were separated into two target 'micro' regions for lint yield evaluation, while all five testing locations provided similar information for fiber strength evaluation. Hence, testing for lint yield in South Carolina should be conducted in two 'micro' regions within the cotton producing areas that include sites located in northeast and southern areas of the state. In contrast, testing for fiber strength in South Carolina can be accomplished using any area within the cotton producing areas of the state without the need to target genotypes to their proper 'micro' location within the state. The results of this study provide valuable information that can be used by cotton breeding programs focused on cultivar development in South Carolina. In addition, this study provides an approach that regionally based breeding programs can use to identify testing locations that efficiently target 'micro' regions and provide the most relevant information within the scope of the breeding program.
Technical Abstract: Plant breeding programs involving a wide range of crop plants routinely practice selection (directly or indirectly) for genotypes that display stability for a given trait or set of traits across testing environments through the genotype evaluation process. Genotype stability for trait performance is a direct measure of the presence and effect of genotype x environment interactions, which result from the differential performance of a genotype or cultivar across environments. The genotype evaluation process also requires selection of the proper field trial locations that best represent the target environments the breeding program is directed toward. In this study, we assessed the extent to which genotype x environment interactions affected agronomic performance (lint yield, gin turnout) and fiber quality (fiber length, fiber strength, uniformity index, micronaire, fiber elongation) in a series of cotton (Gossypium hirsutum) performance trials in twelve location-year environments in South Carolina. Genotype x environment interactions affecting lint yield were larger in higher yielding environments, while interactions for fiber strength were greater for genotypes with lower mean fiber strength values. Two regions within the South Carolina cotton production areas were identified as proper testing locations for lint yield performance, while testing for fiber strength can be accomplished in any location within the statewide cotton production areas.