<p>The lack of soil-phosphorus (P) element will result in plant growth retardation. Plants could survive in P deficiency stress by increasing the ability of P uptake or by increasing the efficiency in the P utilization. The aims of this study were to understand genetic composition of rice genotypes possessing Pup1 locus and to know root and leaf growth responses at different P availability condition. The three rice genotypes (IR74, IR74-Pup1, and Kasalath) were analyzed for their genetic composition using SNP markers. The phenotypic experiment was arranged using a Completely Randomized Design with four replications and performed hydroponically in nutrient solution with different availability of P. The result showed that IR74-Pup1 had 84.4% similarities to its parent (IR74) with 13.6% of donor segments, where the Pup1 locus located. The influence of Pup1 locus<br />introgression on total length, surface area, diameter, and volume of the root varied at each growth stage. IR74 and IR74-Pup1 had root and leaf growth restriction on low P, but Pup1 locus introgression showed better growth performance, both in normal P and in low P conditions. The introgression of Pup1 locus increases plant ability to reduce the impact of growth inhibition<br />caused by P deficiency. </p>