Physiological and genetic basis of superior phosphate uptake and utilization efficiency in the rice landrace...

Low phosphorus (P) availability due to edaphic conditions or the scarcity of P fertilizers restricts agricultural productivity. Various rice-growing regions experience poor P availability. Landraces from these regions, such as Wazuhophek in Northeast India, may provide a source of critical genetic variation needed for developing highly efficient, tolerant rice varieties. This study identifies the physiological and genetic basis of higher efficiency and tolerance in Wazuhophek. Wazuhophek displays higher shoot P content across three different P regimes (0, 15, and 200 µM P) compared with the sensitive parent, Improved Samba Mahsuri (ISM). In 0 µM P, the increased shoot P content of Wazuhophek can be attributed to greater root physiological P use efficiency and improved root-to-shoot P translocation. At 15 µM and 200 µM P, Wazuhophek exhibited a higher crown root number and surface area, with more efficient roots than ISM, facilitating better phosphate acquisition and higher shoot P. Furthermore, the genetic basis was delineated by identifying quantitative trait loci (QTLs) for critical traits. Revealing physiological mechanism of low P tolerance of Wazuhophek provides valuable insights for developing rice varieties suited for nutrient-poor soil. Additionally, the identified QTLs for key traits offer targets for breeding more efficient low P-tolerant rice.