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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #352750
Research Project: Utilizing Conventional and Molecular Approaches to Enhance Seed and Fiber Quality Traits, and Conducting a National Cotton Variety Testing Program

Location: Crop Genetics Research

Title: Testing locations in regional high quality tests for cotton seed quality traits

Author
item Zeng, Linghe
item BRIDGES, WILLIAM - Clemson University
item BOURLAND, FRED - University Of Arkansas

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2018
Publication Date: 4/15/2019
Citation: Zeng, L., Bridges, W., Bourland, F. 2019. Testing locations in regional high quality tests for cotton seed quality traits. Journal of Cotton Science. 23:48-58.

Interpretive Summary: Multiple-location tests for evaluating varieties before their use in large acres of production are necessary because of environmental influence. Determination of an optimum number of testing locations in these tests is critical for reducing program cost. Historical data from 2005 through 2013 in National Cotton Variety Tests (NCVT) were used in this study to analyze how reduction of testing locations affected precision in estimation of variety performance in cotton breeding. Cotton seed quality traits of oil content, protein content, and gossypol content were analyzed with different numbers of locations omitted. When locations were reduced by one, two, and three, the precision decreased by 5.7%, 7.3%, and 9.1%, respectively, compared to that with zero locations omitted. These results suggest that up to three testing locations can be reduced from the future NCVT with a minimum sacrifice of precision in breeding. These results can benefit breeders who participate in the NCVT program on redirecting their research resources to other research projects after the unnecessary testing locations were reduced. This study can also be used by other plant breeders as an example on how to reduce testing locations while maintaining precision in breeding.

Technical Abstract: Significant genotype (G) × environment (E) effects for cotton (Gossypium hirsutum L.) seed quality traits have been identified in previous studies. Significant G × E interactions necessitate multiple-location tests to evaluate seed quality traits which have increased cost in the tests. Reduction of testing locations could trim costs if the analysis of G × E interactions and the efficiency in breeding are not dramatically affected by the reduction. The objectives of this study were: 1) to determine an appropriate reduction of testing locations from multiple-location tests without significant loss in power for detecting G × E effects; 2) determine an appropriate reduction of testing location without significant loss in precision for estimating strain means; and 3) identify a possible megaenvironment for evaluation of seed traits using GGE biplot. Historical data of Regional High Quality (RHQ) tests from 2005 through 2013 were used to address the objectives for three seed quality traits including oil content, N content, and free-gossypol. Significant strain × location interactions were detected in most cases with 5.7%, 7.3%, and 9.1% non-significance when one, two, and three locations were omitted with averages of the three traits. Reduction of locations up to three increased standard error about 25% of those with zero locations omitted. There was no clear megaenvironment identified for seed traits. However, the locations of Lubbock, TX, Stoneville, MS, Florence, SC, and Portageville, MO were identified more representative than others for evaluation of the N content.