Characterization of Rice Germplasm for Tolerance to Nutrient Stress Through Morpho-physiological Parameters

Liquid fertilization is a crucial factor in agricultural production, particularly for crops such as rice, as food demand continues to grow with the global population. This study aimed to evaluate the effect of nutritional stress on the morphophysiological characteristics of 100 rice genotypes and classify them into tolerance levels. A para-hydroponics cultivation system was used, in which 100 rice genotypes were grown for 25 days with varying applications of the Hoagland nutrient solution at 20%, 40%, and 100%. At the end of the experiment, the plants were assessed for the morphophysiological characteristics in both the shoot and root systems. This assessment enabled calculation of the total nutritional response index (TNRI), which classifies genotypes into nutrient-sensitive, moderately nutrient-sensitive, moderately nutrient-tolerant, and nutrient-tolerant categories. The results for most evaluated parameters showed significant reductions (for all genotypes) in plant height, leaf area, number of tillers, total dry weight (all plants parts), root length, root volume, and Fv/Fm. This indicated considerable variation among genotypes under nutritional stress. The TLNRI values ranged from 28,107 for the RU1504186 genotype to 16,294 for the JUPITER genotype. Based on nutrient tolerance, 14 genotypes were classified as nutrient-tolerant, 21 were moderately nutrient-tolerant, 41 were moderately nutrient-sensitive, and 24 were nutrient-sensitive. Furthermore, the correlation between shoot and root characteristics using TLNRI for nutrient tolerance was found to be strong (r2 = 0.36 for shoots and 0.86 for roots). This robust classification will guide future studies aimed at clarifying the role of each nutrient in stress responses.