Genotypic difference in salt tolerance during germination and early seedling growth between a native Libyan cultivar and a Ukrainian cultivar of barley (Hordeum vulgare L.)

Salinity adversely affects productivity of crops in arid regions primarily via impeding seed germination. Barely is an important cereal crop for human and animal feeding. The differential impact of salinity on seed germination of a Libyan cultivar (cv. Rihane) and a Ukrainian cultivar (cv. 10031000) was investigated. Seeds were germinated in the dark in 0, 50, 100, 200 and 300 mM NaCl at 25 ○C. The high germination potential of cv. Rihane, with 200 mM NaCl threshold and moderate reduction at 300 mM NaCl, contrasts the lower germination potential of cv. 10031000 with severe salinity-dependent reduction. The effect of salinity on germination speed was stronger than on germination magnitude. The uniformity and synchrony of germination were comparable in the two cultivars and peaked at mild to moderate salinity followed by sharp reduction at high salinity. The mean germination time and germination lag were longer in cv. Rihane than cv. 10031000 and increased by salinity particularly in cv. 10031000. The length of embryonic axis exhibited more severe salinity-induced reduction in cv. 10031000 than cv. Rihane. Radicle fresh weight was comparable in the two cultivars but plumule fresh weight was higher in cv. Rihane than cv. 10031000. Increasing salinity, severely reduced embryo fresh weight either progressively (cv. Rihane) or beyond a 50 mM NaCl threshold (cv. 10031000). The superior salt tolerance at germination of cv. Rihane over cv. 10031000 points to an inherited trait of barley cultivar adapted to salt-affected, arid regions relative to a cultivar native to a well-watered region.