Salt tolerance of hybrid baby corn genotypes in relation to growth, yield, physiological, and biochemical characters

Soil salinity is a major global concern for sustainable crop production, and proper screening of crop genotypes against salt stress should be a major consideration before recommending a genotype for field cultivation. Germination, growth, yield, physiological, and biochemical responses of 11 hybrid baby corn genotypes (Kasetsart 3, PAC 271, PAC 321, PAC 571, SG 17 Super, CP B468, CP B905, WS 111, WS 9103, Chang Daeng 18, and HY 074656) to five levels of NaCl-induced salinity (0.7 [control], 3, 6, 9, and 12 dS m–¹) were evaluated in a germination trial in petri dishes followed by a polyhouse study to assess genotypic variation of baby corn genotypes in salinity tolerance. Data on various germination traits, growth, yield, physiological, and biochemical parameters were collected. Increasing salinity level above 6 dS m–¹ was equally detrimental for germination and growth of all tested genotypes. Germination response of Chang Daeng 18 genotype to salt stress was the poorest (22.2% germination rate and 7.7% mean daily germination). Growth, yield, physiological, and sodium (Na⁺) accumulation data revealed that SG 17 Super genotype was the most susceptible to salt stress, whereas PAC 571 was the most tolerant. SG 17 Super had 28% lower shoot dry matter, 54% lower cob yield, 25% less membrane stability index, and 158% more Na⁺ accumulation compared with PAC 571. All other genotypes were between slightly salt-tolerant to moderately salt-tolerant category, which was also verified by the Hierarchical cluster analysis. Physiological and biochemical parameters, such as free proline, membrane electrolyte leakage, and membrane stability index, as well as ion accumulation parameter, such as Na⁺, were the most representative of salt stress. Salinity reduced leaf greenness (SPAD value), while net photosynthetic rate, stomatal conductance, and transpiration rate were not affected. Na⁺ exclusion and higher K⁺/Na⁺ ratio in leaves of baby corn genotypes correlated well with their higher salinity tolerance, and greater K⁺/Na⁺ discrimination was shown by salt-tolerant genotypes. The relative susceptibility of baby corn genotypes to salinity should be taken into consideration for plant breeding programs. The selected salt-tolerant baby corn genotypes have potentials for cultivation in salt-affected soils for better productivity.