Effects of water stress on germination indices in four genotypes of Bromus inermis

Seed germination is one of the important stages of growth which is a basic requirement for determining optimum plant density in rangeland and farm. This property is affected by many biotic and abiotic factors including ability of genotypes to tolerate water stress imposed by environmental factors. The current research was conducted in germinator to find the behaviour of some Bromus inermis genotypes in relation to water stress at germination and initial growth stages. A split plot design based on randomized completely block design was performed. Genotypes included Alborz 303, Mazandaran 3151, Firouzkouh 3966 and Esfahan 200060. Water stress levels were -3,-6, -9 bars and distilled water. Properties of germination percentage, root & shoot lengths, seedling length, rootlet length to shoot length rate, seedling dry weight, seedling fresh weight, dry to fresh weight rate sprouting rate and seed vigor index were determined during the study. Results indicated that all of the properties, except dry weight to fresh weight ratio of seedling, were decreased due to increase of stress levels. The most decreased ratio was related to change of stress level from -3 to - 6 bar. Among different genotypes, Esfahan 200060 showed the highest germination percentage and had a meaningful preference to other genotypes. From assessed parameters, seedling length and seed index standard showed the most possible reaction to changing water potential. In this study, the best levels to assess resistance to drought were the -6 and -9 bars potentials.