Identification of Drought-Tolerant Tomato Genotypes Using Multi-trait Index at Early Growth Stage

This study is aimed to assess and compare the performance of various elite tomato genotypes under controlled conditions and drought stress induced by 10% polyethylene glycol (PEG-6000). Fifty-three tomato inbred lines were evaluated for their drought tolerance potential under control and 10% polyethylene glycol (PEG-6000) induced drought stress in growth chamber. The study employed a completely randomized design with three replications. Germination percentage, seedling vigor index, germination rate index, mean germination time, and various morphological traits were measured. Genotypes and treatments showed significant differences based on descriptive statistics. Drought stress led to a decline in germination percentage, accompanied by variable changes in root length, shoot length, root/shoot ratio, root numbers, and biomass. A principal component analysis identified key traits influencing variation (58.3%), highlighting complex interrelationships between germination and morphological features. All the traits were positively correlated with each other except mean germination time. Twenty-six genotypes excelled in both control and stress conditions, while 17 genotypes displayed remarkable drought tolerance and germination performance. The manuscript discusses drought stress's adverse effects on tomato seed germination, root and shoot growth, and biomass. It underscores the role of root development in drought tolerance. Some genotypes showed promise for drought tolerance, indicating their potential in breeding programs. The multi-trait genotype-ideotype distance index (MGIDI) proved useful in genotype selection. The study reveals that drought stress significantly affects tomato seed germination and growth, with several genotypes showing substantially higher drought tolerance than the others, indicating their potential for inclusion in future breeding program.