Evaluation of Cotton Germplasm Against Salt Stress for Development of Salt-Tolerant Genotypes

Erratic precipitation patterns under the climate change scenario are leading to secondary salinization in arid and semi-arid regions, especially in Pakistan. The problem is particularly severe in south Punjab, where cotton and wheat are the primary crops. The development of salt-tolerant cotton genotypes is therefore a priority research area. In the first experiment of the current study, 70 genotypes of Gossypium hirsutum were screened using germination test under control (1.2 dS m(-1)) and three salinity levels (7, 14, and 21 dS m(-1)) in glass Petri dishes. In the second experiment, plant growth parameters including root length (RL), shoot length (SL), root fresh weight (RFW), shoot fresh weight (SFW), root dry weight (RDW), and shoot dry weight (SDW) of the same genotypes were studied by growing in plastic bags (4 '' x 8 '') to avoid root loss (only at the control and 20 dSm(-1) levels), to comprehensively assess the genetic variation of salt-stress tolerance among the existing germplasm. Based on performance under two screening experiments, tolerant genotypes of Gossypium hirsutum were selected. A significant reduction was observed in all seedling characteristics measured under salt-stress (20 dSm(-1)) compared to non-saline (control) conditions. Based on a screening test, it was observed that CIM-707 showed maximum salt tolerance (20 dSm(-1)), followed by IUB-13 and FH-900. In contrast, IUB-222, Tarzen-3, and CH-58 showed maximum reduction in growth attributes and were categorized as susceptible varieties. The evaluated tolerant genotypes could be a valuable resource for cotton improvement to salinity stress. The selection of salt-tolerant genotypes will serve as a valuable contribution to the farming community.