Application of hydrotime concept to predict seedling emergence of spring barley varieties in field

Hydrotime is a method to describe the relationship between water potential and seed germination rates and percentages. Hydrotime analysis quantifies the germination rate (θH), germination tolerance to water stress (Ψb) and uniformity of germination (σb) in a seed sample which are major indicators for seed vigor. In order to investigate the possibility of hydrotime model application (based on Inverse-normal distribution) to predict the seedling emergence of barley in field, experiments were conducted on seven spring barley (Karoon, Zahak, Nimrooz, Hull-less, Jonoob, Reyhaneh and Behrokh) in seed technology laboratory and research farm of Ramin Agriculture and Natural Resources of Khuzestan. For this, the effect of reduced water potential on seed germination of barley varieties was described using the hydrotime model. Then, correlations among the output parameters of the hydrotime model and seedling emergence of barley varieties in field were investigated. Results showed that there were no significant differences among varieties in terms of standard germination percentage (P=0.2719), but seedling emergence percent in field significantly affect by variety type (P<.0001). There were significant negative correlation between field emergences of barley varieties with scale (σ; with a correlation coefficient of -0.5709), mean (with a correlation coefficient of -0.8768), median (Ψb(50); with a correlation coefficient of -0.8769) and mode (with a correlation coefficient of -0.7039) of basic water potential (Ψb(g)) distribution (P<0.01). According to the results, the seedling emergences of barley varieties in field increased with more germination uniformity in osmotic stress levels and higher tolerance of varieties to this stress. Therefore, this model is recommended as one of the seed vigor tests to distinguish strong and weak varieties of barley.