Creation of salt tolerant wheat doubled haploid lines from wheat × maize crosses

Salinity is one of the most serious agricultural problems throughout the world. The objectives of these studies were: 1. to determine if salt tolerance can be enhanced by combining characters related to salt tolerance (salt exclusion, and high growth rate and grain yield in saline conditions) and 2. to study the genetic basis of salt tolerance in doubled haploid (DH) lines developed using wheat (<i>Triticum aestivum</i> L.) × maize (<i>Zea mays</i> L.) crosses. The 47 DH lines in experiment 1 and 22 DH lines in experiment 2 and their parents were grown in a controlled environment cabinet in nutrient solution with or without addition of 150 mM NaCl. Under the saline condition, the DH lines mean was significantly higher than mid-parental values for shoot fresh weight (SFW), shoot dry weight (SDW), root fresh weight (RFW), whole plant fresh weight (PFW), plant height (PH), number of tillers per plant (TNP), number of spikelets per spike (SNS), number of grains per spike (GNS), grain yield per plant (GYP), 100-grain weight (GW) and plant biomass (PB). Some DHs showed trangressive segregation for salt tolerance as determined by greater SFW, SDW, RFW, PFW, PH, TNP, SNS, GNS, GYP, GW and PB than the better parent. The genetic variances were greater than the error variances for all measured characters except K content in saline conditions. Moderate to high heritability estimates were found for all the characters studied in saline and control conditions. Salt exclusion was an important aspect of salt tolerance as Na content of leaves was negatively correlated with all growth characters at an early stage of growth, and with grain yield and yield components. We concluded that the higher salt tolerance of some DHs was due to the combination of genetic characters responsible for salt tolerance and salt tolerance is an inherited character.