SEED GERMINATION AND EARLY SEEDLING GROWTH RESPONSE OF SELECTED SORGHUM (Sorghum bicolor L. Moench) UNDER VARYING SALINITY CONDITION

Abstract

Plant growth is adversely affected by salinity as a result of the disruption of certain physiological processes that lead to reductions in yield quality. Thus, this study was conducted to assess the potential for salt tolerance of the sorghum variety during germination and early seedling growth. The experimental treatments were six sorghum varieties and 4 NaCl concentration levels (0, 60, 120 and 180mM). The experimental design was a completely randomized design in factorial combination with three replications. Germination percentage, seedling shoot and root traits, seedling shoot and root weight, were evaluated. It was found that salt stress significantly decreased root length, shoot length, and seedling shoot and root weight of sorghum plants. The germination rate and germination percentage showed highly significant variation between variety and level of treatment. The seed germination percentage was recorded for Muyira1 (83.33%), Erer (76.66), Melkam (86.66), Fedis-01, Argiti, Muyira1 and Erer (83.333) in 60mM Nacl treatment. The remarkable reduction in germination percent was observed at the highest level (180mM) of salt concentration as compared to control. Among the selected sorghum varieties, Melkam showed the highest seed germination percentage (76.667%). The average shoot growth ranged from 0.633 to 0.766 cm at a concentration of 60mM salinity level. In this study, the average of shoot fresh weight was ranged from 0.700 to 1.06g, 0.600 to 0.800 and 0.433g to 0.633g in 60mM, 120mM and 180mM Nacl concentration respectively. The mean seedling shoots to root ratio ranged between 0.912-1.092 in control, 0.863-1.000in 60mM, 0.821-1.000 in120mM and 0.943-1.000 in 180mM. The shoot to root ration is highly affected in highest salinity level as compared with control. The result of the experiment showed that the varieties Melkam, Fedis-01 and Argiti produced the highest mean values in all of the parameters considered, in all the salt regimes. On the basis of results obtained, genotype Melkam was the most tolerant to salt stress, followed by Argiti. Out of the six varieties, Melkam appeared to be better tolerant to salinity. Therefore, this tolerant sorghum variety should be screened for salinity tolerance in breeding program