Gas Exchange Traits and Biplot Analysis Method can be used as Screening Criteria for Salt Tolerance in Maize (Zea mays L.) Cultivars

Water induced salt stress among other abiotic stress is a main problem and decreases crop productions in arid and semiarid areas of the world. However, selection of salt tolerant cultivars by screening method in solution culture at vegetative stage is an easy and economical way to combat with salinity problems. The present hydroponic study was conducted to evaluate the salt tolerance of some newly approved and candidate cultivars of maize on the basis of gas exchange, growth and ionic traits. Three water salinity levels having different electrical conductivity (EC), sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) were developed and fifteen maize cultivars were grown in Hoagland’s nutrient solution. The results depicted that the highest reduction in plant photosynthetic rate, K+ ion uptake and K+: Na+ under onset of salt stress was recorded in Sadaf, FH-963, FH-722 and FH-793 and the minimal in Sahiwal-2002 and Afgoi. Salt tolerant cultivars uptake less Na+ which depicted that Na+ ion exclusion is positively correlated with salt tolerance and plant photosynthetic rate. Biplot analysis method appeared valuable over conventional relative salt tolerance method due to its graphical evaluation of superior cultivars and grouping of cultivars in a particular environment in the biplot graph.