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Abstract
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The effect of salinity stress during germination, early seedling and vegetative growth on
morphological and biochemical traits was evaluated for 18 genotypes of common bean (Phaseolus
vulgaris L.) at 0, 60, 120, and 180 mM NaCl. Analysis of variance showed that the salinity stress had
significant effect on all traits except shoot to root length and dry weight ratios. Though salinity stress
delayed germination in all accessions, three local landraces, ‘Naein’, ‘Lordegan’ and ‘Talash’
germinated fastest under high salinity (120 mM NaCl). The Na uptake among the cultivars studied
suggested that ‘COS-16’ (1.12 mg/g) and ‘Naein’ (1.07 mg/g) were most tolerant to salinity. Conversely,
‘Cardinal’ (1.89 mg/g) and ‘Talash’ (1.89 mg/g) that had the highest Na uptake were considered as the
most susceptible cultivars. Seeds that germinated rapidly at 60 mM NaCl also germinated rapidly
at 120 mM NaCl. At 180 mM NaCl, several accessions reached 50% germination by 6 days, demonstrating
high genetic potential within P. vulgaris for salinity tolerance during germination.
The biomass of radicles plus hypocotyls decreased with increasing salinity. Cluster analysis
separated the accessions into three groups. Group I included salt sensitive accessions with
late germination, high sensitivity index, and reduced seedling growth. Group II included salt
tolerant accessions with rapid germination, high sensitivity index, and enhanced seedling
growth. Group III only included cultivated accessions corresponding to the CIAT gene pool
with rapid germination, low sensitivity index, and intermediate seedling growth.
Key
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