Enhancing Growth of Upland Rice in Low-Phosphorus Soil by Leveraging Root Morphological Traits

Low phosphorus (P) in the upland ecosystems negatively, influence rice growth and causes significant yield losses. In the present study, 9 upland rice genotypes were screened to identify root traits that support the growth in low P soil in a cement tank. Rice genotypes showed significant (p = ≤ 0.05) variation for number of root tips (NRT), number of root branching points (NBP), total root length (TRL), whole root network area (NA), average root diameter, root volume (RV), root surface area (RSA), first order root length (FORL), and second order root length (SORL). BW01 and ITA01 recorded the highest NRT, NBP, TRL, RV, NA, RSA, FORL and SORL while NERICA04 had the lowest representing 5.8, 8.0, 7.6, 6.8, 9.0, 5.8, and 9.3 differences in these traits under low P soil. NRT significantly positively correlated with NBP, TRL, NA, RV, RSA, FORL indicating the role of different root traits in foraging for soil nutrients. The principal component analysis (PCA) showed that the NRT, NBP, TRL, RSA and SORL are important and effective root traits for selection in rice breeding under low P soil supply. BW01 and ITA01 recorded well developed root system indicating that they are P-efficient than P-inefficient NERICA04 under low P soil conditions. Therefore, BW01 and ITA01 can targeted for cultivation in P deficient soils and also used as donor of novel root traits to improve P-inefficient rice cultivars.