NP and 9311 are excellent population parents for screening QTLs of potassium-efficient rice

High and stable rice yields are critical to global food security, and potassium-deficient soils in East Asia have seriously limited rice production in the regions. It is feasible to screen potassium efficient quantitative trait locus(QTLs) from existing rice varieties to cope with rice production in potassium-deficient areas, and the selection of population parents is the key to locating major QTLs. After a long period of natural selection, potassium efficient rice varieties mainly exist in the region where the soil potassium level is low. The present study chose the representative twelve high-yielding rice varieties in east Asia, firstly, to measure plant height, fresh sheath weight, and fresh blade weight under hydroponic conditions. Based on the difference and consistency of the three parameters, NP as low potassium tolerant, and 9311 as low potassium sensitive rice variety were screened. We further analyzed the relative values of the six parameters of NP and 9311 treated with a culture medium containing different potassium (K+) concentrations and showed that the two varieties significantly differed in multiple low potassium concentrations. Meanwhile, we calculated the coefficient of variation of twelve rice varieties and most of those parameters reached a maximum at 4 mg/L K+, indicating that this concentration was suitable for screening potassium-efficient rice. We also measured the potassium content and the potassium-related traits in NP and 9311 tissues, and found that NP and 9311 significantly differed in potassium translocation. These differences may be responsible for the long-distance transport of potassium from the root to the aboveground part. In conclusion, we identified a pair of parents with significant differences in potassium translocation, which can be used to locate the relevant QTLs with high potassium efficiency to cope with the crisis of soil potassium deficiency in East Asia.

Automated summary

This study selected twelve high-yielding rice varieties in East Asia and screened low potassium tolerant and low potassium sensitive varieties by measuring their plant height, fresh sheath weight, and fresh blade weight under hydroponic conditions. Based on the relative values of these two varieties at different potassium concentrations, significant differences were found at multiple low potassium concentrations. The potassium content and potassium transport traits in plant tissues were also measured, and significant differences were observed between the two varieties. Therefore, it is believed that this pair of parents with significant differences in potassium transport can be used to locate relevant QTLs with high potassium efficiency to cope with the crisis of soil potassium deficiency in East Asia.