Assembly and field evaluation of a set of naturally occurring day neutral cotton landraces under rainfed and irrigated conditions

Authors: Sansbury, Sarah; HUGIE, K - Syngenta; SUBRAMANI, J - University Of Arizona; Campbell, Benjamin

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2026
Publication Date: 2/14/2026
Citation: Sansbury, S.H., Hugie, K., Subramani, J., Campbell, B.T. 2026. Assembly and field evaluation of a set of naturally occurring day neutral cotton landraces under rainfed and irrigated conditions. Journal of Theoretical and Applied Genetics. 139. Article 71. https://doi.org/10.1007/s00122-026-05172-2.
DOI: https://doi.org/10.1007/s00122-026-05172-2

Interpretive Summary: Cotton breeding programs are searching for new sources of genetic variation that can be used to enhance and improve cotton production. One source of genetic variation that has not been utilized is the landrace collection maintained by the US cotton germplasm collection in College Station, TX, USA. The landrace collection has not been fully utilized due to a lack of available and relevant performance data including whether an accession is sensitive to daylength. To address this, we field evaluated the entire upland cotton landrace collection for sensitivity to daylength. Following, we assembled a population of naturally occurring day-neutral accessions and evaluated them, along with eight elite, upland breeding lines and cultivars, over two years for agronomic and fiber quality performance in replicated field trials under rainfed and irrigated conditions. On average, day-neutral landraces produced lint yield and lint percent lower than elite checks while they did not differ from elite checks for seed protein, seed oil, and fiber quality properties. Several day-neutral landraces were identified with desirable lint yield and fiber quality under rainfed and/or irrigated conditions. In total, this large evaluation of day-neutral landrace agronomic and fiber quality performance provides a much-needed resource to facilitate their efficient selection as breeding parents for cotton improvement.

Technical Abstract: The Gossypium hirsutum L. landrace collection (n ~ 2,500), maintained by the US cotton germplasm collection in College Station, TX, USA, has been underutilized in cotton cultivar development programs. Underutilization is due to: 1) the common photoperiod sensitive growth habit of landraces that requires short daylength to stimulate reproductive growth and 2) a lack of relevant phenotypic data for traits of interest in cotton production including photoperiod sensitivity. First, the entire G. hirsutum landrace collection was field evaluated in the southeastern US for photoperiod insensitivity. A total of 186 naturally occurring day-neutral accessions were identified and self-pollinated over 2-3 years to maintain heterogeneity and assemble a total of 216 accessions (including some component lines). Second, the 216 day-neutral accessions, along with eight elite, upland breeding lines and cultivars, were evaluated over two years for per se agronomic and fiber quality performance in replicated field trials under rainfed and irrigated conditions. On average, day-neutral landraces produced lint yield and lint percent lower than elite checks while they did not differ from elite checks for seed protein, seed oil, and fiber quality properties. Several day-neutral landraces were identified with desirable lint yield and fiber quality under rainfed and/or irrigated conditions. In total, this large evaluation of day-neutral landrace per se agronomic and fiber quality performance provides a much-needed resource to facilitate their efficient selection as breeding parents for cotton improvement.