Growth, yield, and fiber quality of cotton plants under drought stress are positively affected by seed priming with potassium nitrate

Growth, productivity, and fiber quality of cotton (Gossypium hirsutum L.), a vital fiber-producing cash crop, are severely affected under drought conditions. Seed priming has a proven role in enhancing crop tolerance to abiotic stress, including drought. The objective of this study was to evaluate the effects of seed priming with KNO3 on cotton productivity and fiber quality under drought stress. A germination experiment was established under laboratory conditions with five treatments of seed priming (non-primed or control treatment, hydropriming, and priming with 2.5, 5.0, and 7.5 g KNO3 L-1). Another experiment under polyhouse conditions based on the same seed priming treatments was conducted under three levels of soil water contents (field capacity [FC] 100%: FC100, 75%: FC75, and 50%: FC50). The results obtained showed that there was a clear reduction in the different parameters tested at FC50 in comparison to FC100 (39-54%, 32-44%, 6-12%, and 7-12% reduction for boll number per plant, seed cotton yield, fiber strength, and leaf relative water content, respectively, across all priming treatments). Seed priming with KNO3 at 5 g L-1 effectively alleviated the detrimental effects originated from drought stress and caused 61-73%, 13-16%, and 16-23% increase in seed cotton yield, fiber length, and fiber strength, respectively, across soil moisture levels when compared with the control treatment. The same KNO3 dose caused an increase of 78% in water productivity in comparison to the control plants at FC50. Priming cotton seeds with 5 g KNO3 L-1 holds promise to obtain synchronized germination, enhance fiber quality, and increase yield, especially under water-limited conditions, thereby promoting economic viability and environmental sustainability. Additionally, this practice enhances water productivity, leading to significant water savings and reduced irrigation costs for cotton farmers. This method could be used as potential technology in advancing sustainable agriculture in water-constraint conditions.