Salt Stress and Sugar Beet Improvement: Challenges and Opportunities

Abstract

Drought and salinity are the major abiotic stresses limiting the production of crops including sugar beet in water-limited environments of the world. With an annual precipitation of 240 mm, Iran is classified as a dry region. Furthermore, more than 21 % of the country’s area is occupied by saline soil. Therefore, it is necessary to adopt strategies that will maximize yields and economic returns from stressful environments while minimizing environmental impacts. Among these are improved cultural practices; breeding of new varieties, which involves screening and selection of the existing germplasm; utilization of novel genes through transgenic modification; application of exogenous osmoprotectants, etc. Although conventional selection and breeding programs are making achievement in enhancing the abiotic stress tolerance of crops, breeding for stress tolerance should be given high research priority to accelerate these efforts. However, the extent and rate of progress gained through conventional breeding programs is limited due to the interplay of mechanisms of abiotic stress tolerance that are controlled by the expression of many genes. Furthermore, current techniques employed for selecting tolerant plants are often time-consuming and expensive. Using advanced molecular techniques, some researchers are showing promising results in understanding the molecular basis of tolerance to abiotic stress and increasing stress tolerance in model species and some crops. These findings emphasize that future research should focus on physiological, molecular, and metabolic dimensions of tolerance to stress to facilitate the development of crops with an inherent capacity to withstand abiotic stresses. Additionally, testing the performance of elite genetic materials under realistic field conditions cannot be overlooked. In this chapter, the challenges and opportunities for improvement of salt tolerance in sugar beet (Beta vulgaris L.) are discussed. Many of the principles, however, apply to most crop species.