Evaluating Salt Tolerance in Doubled Haploid Lines

Seed of the parental varieties and the DH lines were sown in 40 L containers filled with a pine bark/loam based potting mix with premixed slow release fertiliser. The containers were located in a glasshouse at the Mt Pleasant Laboratories in Launceston, Tasmania. Each genotype comprised of three replicates, each of five seeds. The glasshouse experiment was performed during summer (sown on 11^th of February) in 2011 under natural light. The experiment was arranged as a randomized complete block design. The control experiment was not conducted since it has been proved that different varieties or DH lines grown in the same potting mixture but with no salt added showed no apparent symptoms of leaf chlorosis or wilting [23] . The salt treatment was similar to previously described [23] . Salt tolerance was assessed by combining scores for leaf chlorosis and plant survival when most of the DH lines reached booting stage (0 = no damage and 10 = all dead; scores between 0–5 are basically the level of leaf chlorosis and the number of dead leaves and score 6–10 are the percentage of plant survival as well as dead leaves and leaf chlorosis of survived plants). Figure 1 shows the differences among DH lines with low scores for lines showing less chlorosis or good survival and high scores for lines showing severe chlorosis and low survival.