Identification of potential rice lines harboring phosphorus uptake 1 QTL using diagnostic markers

Soil phosphorus (P) deficiency is a major constraint on rice productivity. Identifying donors with better uptake and yield under low soil P is crucial for rice breeding programs. To identify novel rice lines with Pup1 QTL that confer tolerance to P deficiency, 143 rice lines were molecularly characterized using three dominant Pup1 gene-specific markers, K46-1, K46-2, and K46-K. Thirty-seven lines with Pup1 QTLs were further validated using a co-dominant marker, K20-2. The following rice lines were confirmed to have the K20-2 allele: Phoudum, Sangsangba, Moirangphou, Punshi, Heitup-Phou, Kumbi-Phou, Phougak, Wangoo-Phou, Moirangphou-Yenthik, Ayangleima, Heimang-Phou, Kakcheng-Phou, MoirangPhou-Angouba, Phouren-Amubi, KJ-216, KJ-219, KJ-222, TI-15, TI-19, Vandana, NPS-53, NPK-43, SM-686, PB-4, PB-5, Sabita, DRR Dhan-41, and ASG-126. The highest percentage of tolerant alleles (represented as ‘+’) for K46-2 was 67.13%, followed by K46-K at 53.84%, K46-1 at 38.46%, and K20-2 at 20.97%. The lines showing the presence of both dominant and co-dominant markers were evaluated for root length, shoot length, and root volume at the maturity stage under irrigated low soil P field conditions in relation to soil P uptake and growth. Among the evaluated lines, Ayangleima and Keibi-phou had higher root lengths, while Kakcheng-phou and TI-17 had higher root volumes than the checks. These lines could be further explored to understand the uptake and efficiency mechanisms under low soil P conditions.