Contents lists available at ScienceDirect Crop Protection journal homepage: www.elsevier.com/locate/cropro Identification of known leaf rust resistance genes in common wheat cultivars from Sichuan province in China Pu Gao a , Yue Zhou b , Takele Weldu Gebrewahid a,c , Peipei Zhang a , Xiaocui Yan a , Xing Li a , Zhanjun Yao d , Zaifeng Li a,* , Daqun Liu a,e,* a College of Plant Protection, Hebei Agricultural University, 289 Lingyusi Street, Baoding, 071001, Hebei, China b Baoding University, 3027 Qiyi Dong Street, Baoding, 071001, Hebei, China c College of Agriculture, Aksum University, Shire-Indaslassie, 314, Tigray, Ethiopia d College of Agronomy, Hebei Agricultural University, 289 Lingyusi Street, Baoding, 071001, Hebei, China e Graduate School of Chinese Academy of Agricultural Sciences, 12 Zhongguancun South Street, Beijing, 100081, China ARTICLE INFO Keywords: Wheat leaf rust Gene postulation Slow-rusting resistance Molecular marker ABSTRACT Leaf rust, caused by Puccinia triticina (Pt), is one of the most important wheat diseases of common wheat (Triticum aestivum L.). Using resistant cultivars is the most economical and efficient way to control the disease. A total of 86 wheat cultivars from Sichuan province in China were inoculated with 14 Pt races for postulating seedling leaf rust resistance (Lr) gene(s) in the greenhouse. Meanwhile, these cultivars were also planted in Baoding and Zhoukou trial fields for identifying slow leaf rusting genes during the 2014–2015 and 2015–2016 cropping seasons. Twelve specific markers for ten known Lr genes (Lr1, Lr9, Lr10, Lr19, Lr20, Lr24, Lr26, Lr34, Lr37 and Lr46) were also used for molecular marker detection. Based on the results from the gene postulation and molecular marker detection, nine Lr genes (Lr1, Lr2a, Lr26, Lr3ka, Lr30, Lr36, Lr15, Lr37, and Lr46) were identified in 45 cultivars either singly or in combination. Most frequently identified Lr genes were Lr26 in 25 cultivars and Lr37 in 21 cultivars. Less frequently detected genes were Lr1 and Lr46 each in nine cultivars, Lr3ka in five cultivars, Lr30 in three cultivars and Lr36 in two cultivars. Lr2a and Lr15 were found in Chuannong 16 and Chuanmai 1, respectively. Twenty-nine cultivars were found to have slow rusting resistance during the two growing seasons. The results should be useful for selecting cultivars with combinations of genes for effective resistance to grow and in breeding new cultivars with improved resistance to leaf rust. 1. Introduction Wheat leaf rust caused by Puccinia tirticina (Pt) is one of the most important wheat diseases that pose a huge threat to wheat production worldwide. It arises in a wide array of climates wherever wheat is grown causing substantial yield and economic losses. It causes more than 40% production losses when the disease is severe on susceptible cultivars (Khan et al., 2013). In China, more than 15 million hectares of wheat is affected annually. Regular wheat leaf rust epidemics occur in the southwest and northwest, the middle and lower Yangtze River Valley and the southern Huang-Huai-Hai region of China (Huerta- Espino et al., 2011). Significant yield losses were documented in Gansu, Sichuan, Shanxi, Henan, and Anhui provinces of China in 2012 (Li et al., 2014; Zhou et al., 2013). Although the disease can be controlled by using fungicides, the fungus may become resistance to fungicides (Luo, 2009). Moreover, chemical residues in wheat may harm the consumers. Therefore, using resistant wheat cultivars is the most ef- fective, economic, and environmentally safe way to control the disease. So far, 78 Lr genes have been catalogued in wheat (McIntosh et al., 2017). Most of these are major or seedling resistance genes and can be overcome by virulence variations (And and Linde, 2003). However, four Lr genes, namely Lr34, Lr46, Lr67 and Lr68 confer slow rusting resistance despite a compatible host reaction (Caldwell, 1968; Herrera- Foessel et al., 2011; Hiebert et al., 2010; Singh et al., 2011). Slow rusting genes or minor genes provide more durable resistance than major genes. Wheat cultivars with slow rusting resistance genes dis- played longer latent periods, low infection frequencies, smaller pustule size and less spore production (Caldwell, 1968; Zhang et al., 2017). Identifying Lr genes present in wheat cultivars helps to control the disease. Gene postulation and molecular marker detection can be used to identify Lr genes carried by wheat cultivars. Gene postulation based on the gene-for-gene hypothesis (Flor, 1956), has been widely used to https://doi.org/10.1016/j.cropro.2018.09.012 Received 19 January 2018; Received in revised form 16 September 2018; Accepted 17 September 2018 * Corresponding authors. College of Plant Protection, Hebei Agricultural University, 289 Lingyusi Street, Baoding, 071001, Hebei, China. E-mail addresses: lzf7551@aliyun.com (Z. Li), liudaqun@caas.cn (D. Liu). Crop Protection 115 (2019) 122–129 Available online 03 October 2018 0261-2194/ © 2018 Elsevier Ltd. All rights reserved. T