Morphological Responses to Salinity Stress at the Germination Phase in Eight Rice (Oryza sativa L.) Cultivars Cultivated in North Sulawesi, Indonesia.

<b>Background and Objective:</b> The biodiversity of rice cultivars, including local rice from North Sulawesi, represents a potential source of germplasm for fulfilling national food needs. A few publications related to the characteristics of salinity stress resistance in rice cultivars, including local rice from North Sulawesi. This study aimed to examine the morphological response to salinity stress at the germination phase in eight rice cultivars cultivated in North Sulawesi, Indonesia. <b>Materials and Methods:</b> The randomized block design experiment was conducted in the laboratory using eight rice cultivars (Superwin, Ombong, Temo, Burungan, Ciherang, Inpari 31, Inpago 10 and TB) using the Roll Paper Test method during the germination phase. The treatments in this experiment were salinity stress of 0, 10, 20 and 30% seawater for 14 days. The morphological characteristics evaluated as a response to salinity stress consisted of germination percentage, normal germination percentage, root length, shoot length and root-to-shoot ratio. To determine the significant differences and interactions between treatments (where, p<0.05), the data were analyzed using Analysis of Variance (ANOVA) followed by Least Significant Difference (LSD) 5%. <b>Results:</b> Salinity stress reduced germination rates, including overall and normal germination and shorter shoot and root lengths. However, this stress caused an increase in the root-to-shoot ratio. The Roll Paper Test with salinity treatment at the germination phase could be used as a simple selection method to obtain salinity-tolerant-rice cultivars. <b>Conclusion:</b> Shoot length and root-to-shoot ratio were potential morphological indicators for salinity tolerance in rice.