Qiaozhen Li, Chunying Xu, Xiuli Zhong, Xiaoying Liu, Shuying Li and Ennke Liu*
As one of the most important agricultural regions in China, the North China Plain (NCP) is threatened by a serious water-resource crisis due to excessive exploitation of groundwater reserves. The situation urges the region to meet the challenge of conserving groundwater while maintaining high crop production. In this review, firstly, water saving by means of cultivar improvement and reasonable cultivar adoption was discussed. Based on studies around key factors affecting cultivar water use and yield formation, some target traits to be genetically improved were indicated, including stomatal conductance, stomatal drought sensitivity, the traits restricting non-stomatal transpiration and nocturnal transpiration, early vigor, carboxylation efficiency, and harvest index. Also, the strategies were tentatively proposed for appropriately matching cultivars with specific stomatal traits to water availability of local areas. Secondly, irrigation scheduling in the NCP need to be further optimized to markedly conserve groundwater without causing larger yield loss. Irrigation frequencies of four times currently used in wheat could be reduced at least once, depending on soil water status at sowing, jointing, and grain filling stages. Finally, mulching soil surface with maize straw at appropriate amount after trifoliate stage of wheat is expected to bring about evaporation reduction and yield improvement.