Screening of historical and current upland and pima cotton germplasm for resistance to rhizoctonia solani

Authors: GARCIA, JORGE - California State University; Ulloa, Mauricio; HUTMACHER, ROBERT - University Of California, Davis; ELLIS, MARGARET - California State University

Submitted to: BMC Research Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2025
Publication Date: 3/14/2025
Citation: Garcia, J., Ulloa, M., Hutmacher, R.B., Ellis, M.L. 2025. Screening of historical and current upland and pima cotton germplasm for resistance to rhizoctonia solani. BMC Research Notes. 18. Article 113. https://doi.org/10.1186/s13104-025-07161-y.
DOI: https://doi.org/10.1186/s13104-025-07161-y

Interpretive Summary: Diseases affecting small plants or seedling diseases have a detrimental impact in cotton production through all cotton growing regions of the world. Rhizoctonia solani is a soilborne fungus and a prominent seedling pathogen associated with the cotton seedling disease complex. Despite substantial efforts in developing management strategies over the years, seedling diseases remain a significant challenge of cotton production. Relatively few and no recent screenings of cottons have been conducted to identify potential sources of resistance to Rhizoctonia solani. Therefore, the objective of this study was to screen historical and current Upland and Pima cottons for resistance/susceptibility to Rhizoctonia solani. The results of this screening found no significant differences among 85 Upland and 10 Pima cotton entries based on data from infected root rot and fresh root weight. While Upland and Pima cotton make up most cotton grown worldwide, the lack of resistance identified in both historical and newer Upland and Pima germplasm lines suggests a pressing need for further exploration and selection of novel sources of resistance within the vast genetic diversity of different domesticated and wild cotton types. Results from this study provides possible sources of resistance to this pathogen through additional recurrent selection methods and can be used by cotton researchers and breeders.

Technical Abstract: The fungus Rhizoctonia solani is an important seedling pathogen to many plant hosts including cotton (Gossypium). Relatively few and no recent screenings of cotton germplasm have been conducted to identify potential sources of resistance to R. solani. Therefore, the objective of this study was to screen historical and current Upland (Gossypium hirsutum L.) and Pima (Gossypium barbadense L.) cotton germplasm for resistance/susceptibility to R. solani. The results of the R. solani screening found no significant differences among 85 Upland and 10 Pima cotton genotypes, which were all similarly susceptible to R. solani based on data for root rot and fresh root weight. While Upland and Pima cotton make up most cotton grown worldwide, the lack of resistance identified in both historical and newer Upland and Pima germplasm suggests a pressing need for further exploration and selection of novel sources of resistance within the vast genetic diversity of different domesticated and wild cotton species.