Root distribution influences cotton performance
O. P. Ghimire, V. Kuraparthy, M. A. Jones, B. T. Campbell, J. Thomas, S. Rustgi, S. Narayanan
Department of Plant & Environmental Sciences, Clemson University, 105 Sikes Hall, Clemson, SC 29634

Root system architecture plays a pivotal role in improving water and nutrient uptake, thereby enhancing plant productivity. Modern cotton cultivars exhibit limited root activity during critical growth periods due to historical breeding efforts concentrating on above-ground traits. This study focused on assessing root system architecture in relation to above-ground traits, aiming to identify the root ideotype for enhancing cotton performance. Field trials were conducted in Florence, SC, using 20 genotypes from the U.S. cotton diversity panel, representing 74% genetic diversity in the US upland cotton population. The in-situ root imaging technique was adopted to study the root architecture, and the above-ground physiological traits, including leaf area index, biomass, yield, and water use efficiency, were measured. Analysis of variance revealed significant genotypic effects on above and below-ground traits. Clustering analysis identified the top-performing and poor-performing genotypes based on the aboveground traits. The top-performing genotypes showed better root distribution at the deeper root zone than the poor-performing genotypes, and above-ground traits were more strongly correlated with root traits at the deeper root zone. This crucial root ideotype with a distinct pattern of root architecture at different depths will be valuable in the breeding of improved cotton cultivars.