Effect of Salinity on Wheat Genotypes during Germination Stage

Abstract

Salinity is a major abiotic stress that adversely affects wheat production in many regions of the world. Salinity stress limits wheat growth, development, and yield. Identification of salinity tolerant genotypes is critical for yield improvement. Therefore, a series of control environment experiments were carried out to evaluate the response of two spring wheat and two winter wheat cultivars (Triticum aestivum L.) to different levels of salinity. The experiments were designed in a randomized complete block design (RCBD) with five replications. Twenty seeds of each genotype were placed on pre-moistened filter paper in Petri dishes and placed in an incubator at 20 °C. The seeds were subjected to 4 levels of salinity 0, 50, 100, and 150 mM NaCl. Seedlings were harvested after 8 days, and data on final germination percentage, rate of germination, mean daily germination, shoot and root length, and seedling fresh and dry weight were recorded. The results indicated that winter and spring wheat genotypes differed significantly for germination percentages, rate of germination, mean daily germination, shoot and root lengths, and seedling fresh and dry weight. The results showed that salinity did not affect final germination percentage until salinity level reached to 100 mM NaCl; whereas seeds subjected to 100 and 150 mM NaCl retarded germination by 1 and 2 days of spring wheat, and 2-3 days of winter wheat respectively, as compared with 0 and 50 mM NaCl treatment. The data also showed that increasing salinity level significantly decreased shoot and root length, however, the study found that salinity affected root growth more severely than shoot growth of seedlings. Significantly, root length and dry weight of root ranked genotypes in the same order as their salt-tolerance. Therefore, the study concluded that the measurements of root growth would be effective criteria for screening wheat genotypes for salt tolerance at seedling stages.