1.4 Resistance of Chinese Wheat Cultivars

Both major gene-based and partial resistance were used in wheat varieties. Due to the fact that major genes resistance is easily overcome by the pathogen, partial resistance conferring adult-plant resistance (APR), has been paid more attention in wheat production since 1970s. Some APR cultivars such as Libellula, Strampelli, San pastore, Bulgarian 10, Bulgarian 14, Dongfanghong 3, Handan Youzimai, Nongda 168, Nongda 198, Nongda 4356, Nongda 6085, Pingyuan 50, Xuzhou 8, Shaanxi Mazhamai, Qishan Mazhamai, Wangshuibai, Wuming 7, Xiannong 4, Qingnong 1, Qingnong 3, Zhongliang 5, Xiaoyan 6 were widely used and played an important role in Chinese wheat production (He et al., 2011).

During the past decades, 80% Chinese commercial cultivars were susceptible, all-stage resistant cultivars were less than 5% in hotspots areas. During 2003-2008, among 330 commercial cultivars and 194 breeding lines evaluated, only 3.2% cultivars showed all stage resistance, 20.0% showed APR, and 5.7% showed slow-rusting (Zeng et al., 2014). Among 74 Chinese wheat commercial cultivars assessed, only four cultivars showed APR, ten cultivars showed MS-MR at adult stage, the other 60 cultivars showed susceptibility both at seedling and adult stages (Xue et al., 2014).

Trap nursery survey in the year of 2019-2020, recent severe epidemic year in the Chinese yellow rust hotspot Yunnan, indicated that most of Chinese commercial wheat cultivars showed highly susceptible in the field, only a few of them showed good APR, such as Chuanmai 42, Zhoumai 22, Lantian 19, Lantian 31, Chuangnong 27, etc. and Yunnan local released cultivars such as Yunmai 34, Yunmai 56, Yunmai 68, Yunmai 101, Yunmai 110, Yunmai 112, etc. Further efforts will be required for developing new resistant cultivars with diverse genetic background.