In vitro Study of the Effects of Drought Stress on Germination and Seedling Growth of Sugar Beet Cultivars

Drought stress is one of the most important environmental factors which reduce growth, development and production of plants. In order to investigate the effects of drought stress on seed germination of sugar beet, a factorial experimental was conducted based on randomized complete block design (CRD) with three replications. The experimental factors were five sugar beet cultivars (IC, H5505, PP8,7233, BR1) and five levels of water stress (0,-2,-4,-6,-8 bar of polyethylene glycol 6000). The results showed that decreasing osmotic potential had a significant effects on germination, speed and uniformity of germination. Increasing osmotic potential decreased germination percentage, its amount was 8633% in the control treatment and 11% in the osmotic potential -8 bar. The highest germination percentage was belonged to cultivar7233 629%) and the lowes amount was in cultivar H5505 (4266%). Maximum uniformity of germination was obtained in the control treatment and the minimum amount was obtained in the osmotic potential 6 and -8 bar. Minimum uniformity of germination was obtained in the cultivar IC (with 53.47 hours) and the maximum uniformity belonged to the PP22 cultivar (with 36.21 hours). The higher levels of osmotic potential had more inhibition effect on plumule growth than on radical growth. Under water stress condition cultivar 7233 had longer radicle and higher proportion of radicle to plumule than other cultivars. Thus this cultivar was more resistant to water stress.