Iranian Journal of Seed Research

This study was conducted to evaluate the effect of hydropriming and seed aging on germination and enzymatic properties of pinto bean under salinity stress as factorial based on a completely randomized design with four replications. Two groups of seeds (i.e., non-aged and aged seeds), two hydropriming treatments (i.e., hydro primed and unprimed seeds) and six salinity treatments (i.e., 0, 2, 4, 6, 8 and 10 dS/m) were the experimental factors. The results showed that the highest mean time and percentage of germination, plumule length and vigor were observed in the control (i.e., distilled water) and hydropriming treatments. Maximum root length and percentage of seedling water were obtained in the control (i.e., distilled water) and aged seed treatments. In addition, in terms of radicle dry weight, the highest amount was observed in salinity of 4 dS/m and non-aged hydro primed seeds. The highest plumule dry weight was observed in salinity of 6 dS/m and allometric index in salinity of 8 dS/m for non-aged seed and aged seed without hydropriming, respectively. An increase in the levels of salinity stress and aging the seeds increased the malondialdehyde and reduced the activity of germination, mean time and germination percentage, and seedling growth. Seed hydropriming reduced the peroxidation of the cell membrane and generally improved the speed and uniformity of germination, aged and natural seeds vigor under both salinity and optimum conditions. As a result, hydropriming can increase the tolerance of bean seeds to salinity at the germination stage and increase the germination capacity of stored seeds for cultivation.

Extended abstract
Introduction: The germination stage in plants, including wheat, is a susceptible stage to biotic and abiotic stresses. Establishing the plant in the early stages of growth, especially in the germination stage, is always very important. Salinity stress is one of the abiotic stresses that cause much damage yearly, especially in arid and semi-arid regions. Therefore, the identification and use of tolerant cultivars to salinity stress is one of the effective ways to reduce the negative effects of salinity stress.
Materials and Methods: In the present study, the response of 64 spring wheat cultivars at the germination stage in two levels of salinity stress (zero as a control and 12 dS/m of sodium chloride) with two replications was investigated in the form of a simple lattice design in the Genetics Laboratory of the Faculty of Agriculture, Urmia University. During seven days, the characteristics of germination percentage, germination index, germination rate, germination energy, seedling vigor, mean germination time, and mean germination rate, and after the seventh day the characteristics of seedling length, shoot length, root length, ratio of shoot length to root length, seedling fresh weight, and seedling dry weight were measured.
Results: Among the studied cultivars, in terms of all traits including radicle length, shoot length, seedling length, fresh weight, dry weight, radicle to shoot length ratio, germination index, germination rate, germination energy, germination percentage, seedling vigor, mean germination time, and mean germination rate a statistically significant difference was observed at the probability level of 1%. Based on the results of factor analysis, in both normal conditions and salinity stress, the studied traits were grouped into four main factors, and these four factors explained 92.74% of the changes in normal conditions and 93.85% in salinity stress conditions. Using cluster analysis, cultivars were grouped into three and two clusters under normal and salinity stress conditions, respectively.
Conclusions: Based on the results of bi-plot and cluster analysis, the cultivars Moghan 2, Bistun, Akbari, Moghan 3, Dastjardi, Marvdasht, Gahar, and Mahdavi are the preferred cultivars and the cultivars Darya, Bam, Tajan, Sistan, Frontana, Kavir, and Afogh were introduced as undesirable cultivars in terms of traits measured in this experiment, which can be used in breeding projects.

Highlights:

1. A large number of spring wheat cultivars have been investigated in relation to salinity tolerance.
2. Mahdavi, Dastjardi, Bistun, Akbari, Moghan 2, Moghan 3, Gahar, and Marvdasht cultivars were identified as tolerant to salinity stress in the germination stage.