Cotton plays a great role in national economy and people's livelihood in China. Potassium (K) is one of the most important factors influencing crop metabolism, growth, development and yield. However, 3/4 of paddy soils in China are deficient in potassium, because of the limitation of potash resource in the country and the low K fertilizer use. Therefore, screening a broad range of cotton genotypes to identify their differential K uptake and use efficiency is highly desirable.

Potassium uptake and use efficiency are mainly related to the mechanisms of potassium uptake in root system, potassium translocation and distribution to harvested parts of crop. PhD student Ying Xia at the supervision of Professor Fang Chen from Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden used single and double grafting technologies for two different cotton genotypes (103, a high potassium efficiency genotype; 122, a low potassium efficiency genotype) to clarify the main mechanisms of cotton high K use efficiency.

The results indicated the cotton K use efficiency is mainly related to the K translocation and distribution within above ground organs and tissues. The K uptake efficiency was determined by the root and shoot genotypes. Therefore, more dry matter and K translocated into shoot and reproductive organs could be one of the main mechanisms of cotton high K-use efficiency.

Relevant results were published in Journal of Food, Agriculture & Environment entitled “Studies on potassium uptake and use efficiency of different cotton (Gossypium hirsutum L.) genotypes by grafting”.

 Differences in K use efficiency of the different grafts