Screening Guar (Cyamopsis tetragonoloba (L.) Taub.) Genotypes for Salt Tolerance using Physiological Indicators and Yield Performance

Guar (Cyamopsis tetragonoloba) is an important industrial legume widely cultivated across arid and semi-arid regions. To identify salt-tolerant genotypes, the fifteen guar genotypes originating from Iran, India, and Pakistan were evaluated under three salinity levels (۰, ۱۰, and ۱۵ dS/m) in a factorial RCBD design. Salinity imposed highly significant reductions in physiological traits and caused phenological delays in guar genotypes. Under severe salt stress (۱۵ dS/m), seed yield decreased across all genotypes. In response to ۱۵ dS/m NaCl, the lowest yield reductions were recorded for the genotypes S۶۵۵۳, Saravan, S۶۲۶۰, and RGC-۱۰۳۱, at ۱۶.۳, ۲۰.۴, ۲۱.۲, and ۲۱.۴%, respectively, demonstrating relative tolerance to salt. In contrast, the largest decrease was observed in genotypes S-۵۸۸۵, S۶۵۶۶, and S-۶۵۶۰, by ۳۱.۴, ۳۰.۵, and ۳۰.۵%, respectively, confirming their relative sensitivity to salt stress. Although genotypes S۶۵۵۳, Saravan, S۶۲۶۰, and RGC-۱۰۳۱ exhibited the lowest yield reductions at ۱۵ dS/m NaCl, overall, genotype RGC-۹۸۶ consistently displayed superior performance across all salinity levels, while genotype Pishen was the most adversely affected, exhibiting sharp declines in physiological performance and delayed phenology. Inclusive, the study demonstrated substantial genetic variability in guar responses to salinity and highlighted key physiological traits, such as chlorophyll retention, osmotic adjustment, membrane stability, and growth maintenance, as essential determinants of tolerance. RGC-۹۸۶ genotype, identified as salt-tolerant, represents valuable candidates for breeding programs and for sustainable guar cultivation in salinity-affected regions.

کلیدواژه ها:

legume ، galactomannan ، Variation ، Salt tolerance