Multielement stoichiometry of cotton (Gossypium genus) and its improvement potential through the use of genetic variation

According to the geochemical niche hypothesis, different species have unique elemental compositions, but the elemental stoichiometry of cotton ( Gossypium genus) has not been systematically studied. The rich variation and patterns in elemental stoichiometry within cotton can indicate potential directions for breeding. We studied the concentrations of 15 elements (carbon, nitrogen, calcium, potassium, sulfur, phosphorus, magnesium, iron, silicon, manganese, boron, zinc, nickel, copper, and molybdenum) in the leaves of 18 different cotton species grown in a common garden and compared them with global plant averages. Compared with the global plant averages, the cotton had advantages in nitrogen, calcium, potassium, sulfur, phosphorus, boron, nickel, and molybdenum concentrations. Through redundancy analysis, we confirmed that the elemental stoichiometric variation in cotton was mainly influenced by ploidy level, domestication status, and genome type, which indicated that the elemental composition of cotton can be adjusted by changes in these aspects. Magnesium and calcium exhibited strong centrality in the elemental network of cotton, limiting the variation in the concentrations of sulfur, iron, zinc, nickel, and boron. These results enhance our understanding of cotton species and suggest that magnesium should be further enhanced in future breeding.