Effect of Sodium Chloride Salt on Germination, Growth, and Elemental Composition of Alfalfa Cultivars with Different Tolerances to Salinity
2022
Surendra Bhattarai | Seth Lundell | Bill Biligetu
The aim of this study was to evaluate physiological responses and elemental composition of three salt tolerant alfalfa (<i>Medicago</i><i>sativa</i> L.) cultivars, ‘Halo’, ‘Bridgeview’, ‘Rugged’, and two intolerant cultivars ‘Rangelander’ and ‘Vernal’ under five salinity levels (0 dSm<sup>−1</sup>, 4 dSm<sup>−1</sup>, 8 dSm<sup>−1</sup>, 12 dSm<sup>−1</sup> and 16 dSm<sup>−1</sup>) in a sand based hydroponic system in the greenhouse. The germination percentage among the cultivars was highest for ‘Halo’ under salt stress. ‘Rugged’ and ‘Halo’ had higher seed vigor than the other cultivars in 16 dSm<sup>−1</sup> EC. Among the alfalfa cultivars, ‘Rugged’ had the highest chlorophyll content at 0–12 dSm<sup>−1</sup> EC. There was variation for root (<i>p</i> = 0.01) and shoot (<i>p</i> = 0.03) biomass among the alfalfa cultivars. Salt stress reduced (<i>p</i> < 0.001) plant height and shoot biomass, with 4.2% and 7.9% reduction for each 1 dS m<sup>−1</sup> increase, respectively. Shoot biomass showed a positive correlation with plant height (<i>p</i> < 0.001, r = 0.80), chlorophyll content (<i>p</i> < 0.001, r = 0.56), root biomass (<i>p</i> < 0.001, r = 0.51), but was not correlated with seed vigor. This study demonstrated that seed vigor in the germination stage can not be used to predict salt tolerance of alfalfa at mature growth stages, however plant height and leaf chlorophyll content can serve as physiological markers for high shoot biomass selection at mature growth stages under salt stress.
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