Drought stress tolerance mechanisms and breeding effort in sugarcane: A review of progress and constraints in South Africa

Drought stress is a major cause of yield losses in sugarcane production and the frequency of its occurrence in several regions is expected to increase due to climate change. Despite the advancements in conventional breeding and transformation technology, developing sugarcane for drought tolerance remains a major challenge. This is not only due to the complexity of the sugarcane genome but also due to the complexity of the plant responses to water deficit and the difficulty of identifying physiological and morphological traits that can be used for the selection of drought-tolerant varieties suitable for commercial production. This review paper integrates literature on our current understanding of the biological effects of drought stress on sugarcane growth in a way that bridges the signalling networks with physiological and genetical defence mechanisms. Special emphases are given to the technical challenges and prospects associated with the practical application of various breeding techniques used for sugarcane improvement in South Africa such as conventional breeding, transgenic approach and ethyl methanesulfonate induced mutations.