RICE SELECTION CRITERIA BASED ON MORPHOLOGICAL AND IMAGE-BASED PHENOTYPING UNDER DROUGHT- AND SALINITY-STRESS CONDITIONS

Abstract

Image-based phenotyping in selecting drought- and salinity-tolerant rice lines is a potential approach to complement other selection criteria. This study aimed to determine tolerance response and selection criteria on drought and salinity stresses based on a morphological and image-based phenotyping character. The experiment, set up in a screen house of the Department of Agronomy, Faculty of Agriculture, Hasanuddin University, Indonesia, consisted of a nested randomized complete group design. The nested replication included stressed environments with two factors and three repetitions. The level of environmental stresses comprised the first factor, i.e., normal (without NaCl and PEG), salinity (60 and 120 mM NaCl), drought (10% and 20% PEG), and combination of drought-salinity (10% PEG + 60 mM NaCl). The second factor entailed the rice genotypes. Observations of the morphological and image-based phenotyping characters ensued. The results indicated that salinity stress had a wider diversity than drought stress, while the multiple stresses had a relatively stable variety compared with single stress. Morphological and image-based phenotyping character increased precision in assessing the tolerance or adaptability of rice to drought stress, salinity, and its combination. The morphological characters that can serve as rice selection criteria in a combination of drought-salinity stress included the shoot and root fresh weights and the root length. As for the image-based phenotyping character, the shoot phenotype width can serve as the selection criterion. Image-based phenotyping characters, especially the shoot phenotype area, were recommended as criteria for precise selection in assessing rice genotypes’ potential tolerance and adaptability to drought stress, salinity, and its combinations.