Document Type : Original Article
Abstract
Seed deterioration and environmental stresses effects on seed germination are important factors limiting germination percentage (GP) and emergence homogenecity under field conditions. In order to study the effect of deterioration degree and artificial drought stress on wheat seed germination and seedling parameters; a factorial experiment were conducted based on a randomized complete block design with four replications. Treatments were seed deterioration degree (control, 65 and 130 hrs at 100% RH and 41±0.3 °C), cultivars (Shahpasand, Azar2, Shahriar, Alvand and Zarrin) and artificial drought stress applied with PEG6000 (control, -3 and -6 bar). Results showed that 130 hrs deterioration and -3 bar stress had the lowest germination rate (GR) in Azar2, while the lowest GP for this cultivar was observed under 65 hrs deterioration and -6 bar stress conditions. The shortest radical and plumule obtained from Azar2 and Shahriar at 65 hrs stress and -6 bar stress level. With increasing deterioration and stress levels, the seedling dry weight decreased in all cultivars. The greatest seed reservoirs using rate (SRUR) achieved in Shahriar cultivar at control levels of deterioration and stress, while the lowest value in Azar2 at 130 hrs deterioration and -6 bar drought stress. The lowest value for seed reservoir using efficiency (SRUE) was observed at Azar2*control deterioration*control stress, but the lowest value for FMSR at Azar2* 130 hrs deterioration* -6 bar stress. It is concluded that the cultivars are different genetically in seed reservoir consuming at germination and the deterioration level is more important in seed vigor decrease than drought stress. Therefore, parameters studied in this research specially SRUR are useful in screening of cultivars for high seed vigor
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