Salt Stress Effects On Hybrid Bottle Gourd (Lagenaria siceraria) Rootstock Candidates Plant Growth, Hormones and Nutrient Content

Globally, salinity has a devastating effect on plant yield and quality. The breeding of salt-tolerant varieties/rootstocks is crucial to reducing these effects. This study involved 35 hybrid rootstock candidates, their female and male parent lines, 9 genotypes ( Lagenaria siceraria ). In hydroponic conditions, rootstock candidates were evaluated for the biomass, physicochemical parameters in leaf and root tissues under control [1.8 dS m −1 ] and saline [10 dS m −1 ] conditions. Salt stress reduced shoot dry weight by 63%, root dry weight by 43%, main stem diameter by 18%, number of leaves per plant by 41%, main stem length by 68%, and root length by 45%. Under salt stress, the highest amount of photosynthetic parameters were measured in genotypes 39-01 × 56-01 (16.17 µmol CO 2 /cm 2 /s) and 42-11 × 47-02 (16.47 µmol CO 2 /cm 2 /s), respectively. Salt stress decreased leaf tissue IAA (3%), ABA (63%), and root tissue IAA (28%), GA 3 (32%), and SA (63%) content, but increased leaf tissue GA 3 (196%), SA (27%) and root tissue ABA (47%) content. Salt stress decreased leaf K/Na and Ca/Na ratios by 100 and 97%, respectively, under salt stress. The increase in the amount of K/Na and Ca/Na in leaf tissues under salt stress conditions positively affected biomass and photosynthesis parameters. In this study, 15 Lagenaria hybrid rootstock candidates performed better under salt stress than watermelon and other hybrids salt-tolerant plants. It has been concluded that rootstock candidates selected as salt tolerant can be used as watermelon rootstocks in regions experiencing salt stress by determining their rootstock/scion interactions in terms of yield and quality in future studies.