Assessing the weed-suppressing potential of cotton Chromosome Substitution Lines using the Stair-Step Assay

Authors: FULLER, MARY - Mississippi State University; Saha, Sukumar; STELLY, DAVID - Texas A&M University; Jenkins, Johnie; TSENG, TE-MING - Mississippi State University

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2021
Publication Date: 11/13/2021
Citation: Fuller, M.G., Saha, S., Stelly, D.M., Jenkins, J.N., Tseng, T.P. 2021. Assessing the weed-suppressing potential of cotton Chromosome Substitution Lines using the Stair-Step Assay. Plants. 10:2450. https://doi.org/10.3390/plants10112450.
DOI: https://doi.org/10.3390/plants10112450

Interpretive Summary: Palmer amaranth (Amaranthus palmeri) is a difficult weed commonly present in Upland cotton field. The discovery of any cotton germplasm with genetic potential to impede the weed growth and development will provide economic benefit to the farmers because weeds compete with the crop for its nutrition and water in the same farm field. The overall objective of this research to identify cotton chromosome substitution (CS) lines with genetic potential to have negative impact on the growth and development of Palmer amaranth. A stair step method in greenhouse was used to study the effect of individual CS line which provided scope to study the effect of individual CS lines on the growth and development of Palmer amaranth weed without any interference of other external factors in the greenhouse. Eleven CS lines (CS-B26lo, CS-T17, CS-B16-15, CS-B17-11, CS-B12, CS-T05sh, CS-T26lo, CS-T11sh, CS-M11sh, CS-B22sh, and CS-B22lo) were screened for weed-suppressing abilities in this study. Results indicated that CS-B22sh had the highest effect in reducing Palmer amaranth height and chlorophyll concentration with the most heightened susceptibility for Palmer amaranth. Results from cluster analysis revealed that the transgenic herbicide tolerant Enlist cotton line was grouped with CS-CS-B22sh, and CS-T26lo in one group suggesting similar genetic potential with reference to Palmer amaranth growth and development. In the future, it will be interesting to investigate if CS-B22sh exudates from its root any chemical that impeded the growth and development of Palmer amaranth.

Technical Abstract: Palmer amaranth (Amaranthus palmeri) is a problematic common weed species, especially in cotton (Gossypium hirsutum). With the wide use of chemical herbicide and herbicide-tolerant transgenic cotton lines, Palmer amaranth populations have developed tolerance to commonly used herbicides. It is imperative to develop alternative weed control methods to slow the evolution of herbicide-resistant weed populations and provide new sources for weed management. Eleven chromosome substitution (CS) cotton lines CS-B26lo, CS-T17, CS-B16-15, CS-B17-11, CS-B12, CS-T05sh, CS-T26lo, CS-T11sh, CS-M11sh, CS-B22sh, and CS-B22lo were screened for weed-suppressing abilities in this study. The cotton lines were tested using the established stair-step structure methodology, which provided scope to study the effect of individual CS lines on the growth and development of Palmer amaranth weed without any interference of other external factors in the greenhouse. Height (cm) and chlorophyll concentration (cci) were measured for each plant in the system. The data were analyzed as a randomized complete block design using LSD mean comparisons of the genotypes at the P= .05 level. The 14th day after establishment resulted in the most significant variation in Palmer amaranth height reduction among the CS lines. Results indicated that CS-B22sh had the highest effect in reducing Palmer amaranth height and chlorophyll concentration with the most heightened susceptibility for Palmer amaranth. The cluster analysis revealed that Enlist cotton, CS-CS-B22sh, and CS-T26lo were clustered in one group suggesting similar genetic potential with reference to Palmer amaranth growth and development. CS-B22sh showed novel genetic potential to control the growth and development of Palmer amaranth, a major weed in cotton fields. In the future, it will be interesting to investigate if CS-B22sh exudates from its root contain allelelochemicals able to impede the growth and development of Palmer amaranth.