Authors: G.H.Abbasi, M. Noman Tahir, M.Anwar-ul-Haq, Moazzam Jamil
Salt and drought stress is the major constrains to crop productivity worldwide. A pot study was conducted to evaluate the morpho-physiological, ionic and yield attributes to cope with these stresses in two cotton varieties (FH-901 and NIAB-777). Five water levels (control, saturated water contents, field capacity (FC), ½ FC and ¼ FC) and two salinity levels (control and 10 dS m-1) were applied in ten combinations. Results of study revealed that water and salt stress have deleterious effects on growth, photosynthetic activities and yield attributes of both cotton varieties. Fresh and dry weight, shoot length, no. of bolls per plant and boll size have shown reduction under water stress and salinity, but only root length was found highest under mild water stress in order to explore more area for water and nutrient, while salinity still have adverse impact on root length. Optimum photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs) and total chlorophyll contents have been observed under FC in both saline and non saline conditions. A gradual reduction in these parameters was observed with reduction in water content. Salinity have decreased K+ concentration in leaf sap, while Na+ concentration in leaf sap have dramatically increased under saline condition. The results showed that NIAB-777 variety exhibit more efficient stress protection mechanisms to survive under salinity and water stress than FH-901 variety.
Keywords: Salinity. Cotton, Yield, Ions