Salinity Screening - 120mM solution. CONDITIONS: Growth Chamber - 16h light at 25C METHOD NARR: Plantlets were grown in media containing various salinity levels. The single-node cutting bioassay produced data on root lengths and fresh & dry weights at each salinity level. The root tip segment bioassay produced data on root extension growth relative to growth in control medium, for both solid and liquid medium. The microtuberization bioassay produced data on microtuber yield and size distribution per container. The lysimeter experiment measured tuber yield and grade per plant. RESULTS NARR: Plantlet growth parameters were not affected by 40mM NaCl, while 80 and 120 mM NaCl significantly reduced all plantlet growth parameters compared with control and each other in the single-node cutting assay. In the root tip segment assay, the impact on root growth was less in liquid than in solid medium in 40 & 80mM NaCl, but similar in the 120mM treatment. All genotypes were inhibited at 40mM/solid except PI473403. AUTHOR EXPLANATION: It appears that salinity tolerance can be credibly evaluated in vitro. Low to mid-range salinity levels cannot be used to predict genotype tolerance at higher levels. None of the 6 growth parameters used in the single-node cutting assay was a better indicator of salinity ranking than any of the others. The single node cutting assay is recommended as the best in vitro screen.