Iranian Journal of Seed Research

Germination is the first and the most stages for sainfoin (Onobrychis viciifolia) growth; which it has especially sensitivity to environmental stresses such as alkalinity. The current study was conducted to evaluate the effectiveness of seed pre-treatment methods on improving sainfoin tolerance to alkali stress in germination, early growth and its recovery as a factorial experiment based on a completely randomized design in College of Agriculture, Shiraz University in 2013. The first factor was four seed pre-treatment methods (seed with the pod, seed without the pod, pre-chilling of seed without pod and hydro-priming of seed without pod) and the second factor was five alkali stress levels (pH= 6.7, 7.9, 8.9, 9.8 and 10.7). Alkali stress levels were prepared using two neutral salts (Na₂SO₄ and NaCl) and two alkaline salts (NaHCO₃ and Na₂CO₃). The results showed that germination percentage was decreased as alkalinity (pH) levels were enhanced; so that, there were no germinated seeds in 9.8 and 10.7 treatments. Alkali stress reduced initial germination percentage (51.9%), final germination percentage (51.8%), plumule length (55.7%) and radicle length (72.2%). Under all alkalinity conditions, the lowest seed germination and seedling growth were observed in with pod seed, followed by pre-chilling treatments; while their highest were achieved in without pod seeds and hydro-priming treatments. The highest recovery was observed in without the pod, followed by hydro-primed seeds. Recovery was observed in Pre-chilled and with pod speeds up to 7.9 and in hydro-primed and without pod speeds up to 8.9.

Extended Abstract
Introduction: Weeds, as the most important biological stress, reduce the efficiency of water use, waste of food, shading and secretion of toxic substances, leads to a 10 to 100 percent reduction in crop yields. The first step of the weed control understands the biology and life cycle of the weed particularly seed Eco physiological characteristics. Dormancy in weed seeds, including Redroot Pigweed seeds, is common. So, due to the importance of dormancy breaking and germination studies of weed seeds, the present study was designed to identify the methods for dormancy breaking and the germination of Redroot Pigweed seeds.
Materials and Methods: This research started in autumn 2013 by collecting Redroot Pigweed seeds from fields of Alajujeh village, Khoda Afrin County, East Azerbaijan Province, and then it was carried out at the Laboratory of the Faculty of Agriculture of the University of Maragheh in 2014 and 2015. For data analysis, the GenStat 12.1 program was used and the Duncan test was used at 5% probability level to compare the averages. Excel 2013 was also employed for drawing the diagrams.
Results and discussion: Analysis of variance demonstrated that the effect of treatments on germination percentage and germination rate in Redroot Pigweed seeds at 1% probability level and the mean germination time at 5% probability level was significant. The results showed that among studied treatments, seeds holding for 18 months were most efficient seeds dormancy breaking at Redroot Pigweed. So that the highest germination percentage (92%), germination rate (29.18 seed/day) and lowest the mean germination (4.2 day) time were obtained in seeds holding treatment. Pre-chilling treatment also had significant effects in stimulating germination. As regards treatments of seed holding in low temperature and Pre-chilling accelerate the germination process and increase germination percentage, so, having precise information of these traits enables to study, a better management and control of this troublesome weed.
Conclusions: In general, the results of this study show that among the treatments, holding seeds for 18 months at 6 ° C is the best method for solving Redroot Pigweed seeds weeds.

 
Highlights:
1- Seed holding in low temperature and Pre-chilling accelerates the germination process.
2- Seed holding in low temperature increases germination percentage.