Yield assessment of F6 generation tomato lines under irrigated and drought environments based on stress tolerance index

The stress tolerance index is widely used to detect genotypes' tolerance levels under stress conditions, such as tomato plants. Therefore, determining secondary characters requires an appropriate statistical approach, one of which is the concept of multivariate analysis. This study aims to determine the main secondary characters and select tomato lines that are adaptive to drought stress. The research was conducted in parallel at 2 locations from August to December 2023 at the Experimental Garden of the Faculty of Agriculture, Hasanuddin University, located in Tamalanrea District, Makassar City, at an altitude of 12 m above sea level and the Maros Youth Learning Center Garden, Purnakarya Village, Tanralili District, Maros Regency at an altitude of 31 m above sea level, South Sulawesi. This study used Augmented design with Nested Design as the environment design. Location 1 irrigated environment and location 2 drought stress comprised 126 genotypes of 121 F6 lines and five parental varieties (Karuna, Mawar, Chung, Gustavi, and Gammara). This study consisted of 5 blocks; each genotype consisted of 8 plants in each location. The stress tolerance index analysis results showed that the 12 best tomato genotypes have adapted to drought stress, namely genotypes MC10. 4.5.5, KM23.3.3.10, MC74.12.8.1, MC10.7.2.3, MC12.3.2.1, MC29.4.6.4, KM5.3.4.12, MC8.3.3.2, MC10.7.2.1, MC79.2.7.9, MC8.11.5.1 and MC27.12.1.6. These genotypes were selected based on a comprehensive performance review across all measured parameters. Based on the overall review, the results of this evaluation are recommended as a consideration for the selection of F7 lines in supporting the direction of releasing tomato varieties from environmentally adaptive results.