Researchers in the United States are working to help cotton grow as a perennial plant from its current annual yield to help farmers crop better with a higher quality fibre.
- The study hopes to lead to breeding methods that would develop annual-type cotton plants which will help cotton plants to use more energy to produce higher-quality lint, resulting in more profits for growers.
The research: The cotton plant growth habit and structure determine its productivity and influence management strategies for production. The researchers are looking at how regulating certain genes can transform cotton from a perennial plant to an annual plant, as well as genes that control the number of bracts, small leaf-like structures that protect the plant’s floral buds, or squares, against bollworms and other pests.
- The researchers are looking at how plants use environmental and hormonal cues to transition from vegetative growth to reproduction. Reproductive development begins 4-to-5 weeks after planting when squares form. During this stage, bracts surround the squares.
- Perennial crops usually grow in environments that may have limitations such as short growing seasons or dry climates, or where plants’ ability to access resources may be limited.
- Perennial plants store reserves such as carbohydrates, fats and proteins to use for regrowth. In many plant species, this process produces root and shoot buds that can grow into new plants. This is called “vegetative reproduction.”
- Because of its growth habit, cotton continues to add vegetative growth at the same time as reproductive development, diverting the plant’s energy away from lint and seed production.
The experiments: During this study, researchers injected the tobacco rattle virus into cotton plants to finetune the balance between vegetative and reproductive growth.
- The virus was used to manipulate a cotton gene associated with bract development to help prevent a fourth bract from appearing.
- When injected into a cotton plant, the tobacco rattle virus ‘knocks down’ the gene associated with the fourth bract and just three bracts are produced. Compactly packed bracts make it more difficult for insects to attack the bolls.
- The tobacco rattle virus also was used to manipulate a cotton gene associated with plant growth.
Upland cotton cultivars used in this study are Coker 201, CABD3CABCH-1-89, ARKOT 8102, HOPI MOENCOPI, SPNXCHGLBH-1-94, CAHUGLBBCS-1-88, TAMCOT SP-23 and GSA 74.
The Team: The team is being led by Sachin Rustgi, Scientist at the Advanced Plant Technology Program at Clemson’s Pee Dee Research and Education Center (REC) near Florence in South California; Salman Naveed, a Clemson doctoral student; Clemson graduate student Seyi Toyinbo and Clemson technicians Nitant Gandhi and Sarah Rawlins. Mike Jones, Clemson Extension cotton specialist, and Todd Campbell, USDA-Agricultural Research Service research geneticist, also are involved. This research is being supported by the South Carolina Cotton Board and Cotton Incorporated.
The backdrop: The United States is the world’s leading cotton exporter, providing about 35% of global cotton exports in recent years. Figures from the United States Department of Agriculture show almost 18 million bales of cotton were produced in the United States in 2021.
- In addition to South Carolina, other major cotton-producing states are Alabama, Arizona, Arkansas, California, Georgia, Louisiana, Mississippi, Missouri, New Mexico, North Carolina, Oklahoma, Tennessee, Texas, Florida, Kansas, and Virginia.
WHAT THEY SAID:
Right now, cotton is planted and grown as an annual plant, but it is really a perennial plant. If we can develop an annual variety for cotton, we believe South Carolina farmers will benefit by seeing a higher yielding cotton with higher quality fibre.
— Sachin Rustgi
Scientist, Advanced Plant Technology Program
Clemson’s Pee Dee Research and Education Center