Research progress on improving wheat drought tolerance via exotic gene introduction

Water shortage has been identified as a critical issue of sustainability in the North China Plain, a main grain production base in China. It has directly threatened agriculture production in the region and the country at large. Wheat (Triticum aestivum L.), a major cultivated crop in the world, has become an economically viable crop in North China. Breeding drought-tolerant wheat varieties has proven to be an effective approach to limit drought losses in the region. However, inadequate genetic diversity within the Triticum family has hindered progress in developing improved drought tolerant wheat varieties. Exploitation and application of tolerant alien genes from related wheat genera and species have been achieved through distant hybridization of wheat and specific wild grasses. An entire genomic DNA injection technology delimited species barrier and made it possible to transfer exotic genes into wheat from any related or non-related species. Transgenic wheat also opened up a new era of pyramiding drought-related genes of different origins to increase drought tolerance. Using these technologies as take-off point, this paper reviewed relevant progress in wheat drought tolerance improvement.