Genotypic variations in morphological and yield attributes in flax (Linum usitatissimum L.) under salt stress

Flax is one of the most ancient and beneficial crops for its high-quality fibre and edible oil. However, increasing soil salinity due to global warming is one of the main obstacles of agricultural productivity. To investigate the effects of salt stress on seed germination, growth and yield, 2 experiments were conducted in the growth chamber and field laboratory of the Department of Crop Botany, Bangladesh Agricultural University on 40 flax genotypes. In germination and seedling growth experiments, 4 salt levels such as 0 (control), 40, 80 and 120 mM were applied. The second experiment was carried out to evaluate the growth and yield performances of the selected ten flax genotypes with 2 salinity levels: i) Control (0 mM NaCl) and ii) Salinity (100 mM NaCl). Salt stress notably retarded seed germination, seedling growth, yield and yield-attributing descriptors in all flax genotypes. The salt tolerance index (STI) values of all studied parameters in the first experiment were used for the hierarchical clustering of genotypes. Cluster II comprised of 16 genotypes with higher STI scores showing greater salt tolerance. Among them, the genotypes BD-10710, Faridpur, BD-10700 and BD-10703 performed better in relation to salt tolerance. In the second experiment, a greater extent of salt tolerance was observed in BD-10710 and BD-7145 genotypes considering the traits plant height, stem diameter, branch (no.) plant?1, filled capsule plant?1, seed (no.) capsule?1, 1000-seed weight, seed yield plant?1 and yield stability index. Therefore, these 2 genotypes can be suggested for the cultivation in coastal areas of Bangladesh with further field trials and investigations.