Abstract
Drought is one of the significant abiotic stress factors that affect plant development and productivity. Screening and producing of more tolerant genotypes with higher yield capacity is the breeders' principal purpose. Therefore, this work was carried out to evaluate the performance of four sugar beet cultivars (Top, Hossam, Hercules and Kawamera) under water limitation. The drought stress experiment was applied based on three water regimes, 25%, 50% and 75% (severe, moderate and non-stress conditions, respectively) of relative water capacity (RWC). The study incorporated some productivity and quality traits. The results showed that drought stress has a significant effect on all studied traits. Whereas, increasing of water deficiency led to decrease of the productivity traits and increasing of quality parameters. Kawamera cultivar has superior performance in all the studied traits under all three different levels of water regime. Besides, the four cultivars were assessed by both SSR and ISSR molecular markers. SSR marker exhibited a higher polymorphism percentage (71.43%) than ISSR marker (44.26%). In addition, the mean polymorphism information content (PIC) value was higher for the SSR marker (0.25) than the ISSR marker (0.18) too. Moreover, the constructed dendrograms revealed that the SSR marker was able to separate the cultivars according to their drought-tolerance, where the highest drought-tolerant cultivar (Kawamera) was classified alone in the main cluster. However, the superiority of Kawamera cultivar under drought stress indicated that it could be utilized in breeding programs for developing more drought-tolerant sugar beet cultivars.