QTL Mapping and Validation of Adult Plant Resistance to Stripe Rust in Chinese Wheat Landrace Humai 15.

Feng-Ping Yuan,Bang-Ping Liang,Jian-Hui Wu,Zhen-Sheng Kang,Qing-Dong Zeng,Xin-Hong Chen,Qi-Lin Wang,Zu-Jun Yang,De-Jun Han

doi:10.3389/fpls.2018.00968

Abstract

Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is a devastating foliar disease that affects common wheat and barley throughout the world. The reasonable deployment of adult plant resistance (APR) wheat varieties is one of the best methods for controlling this disease. Wheat landraces are valuable resources for identifying the genes/QTLs responsible for disease resistance. Humai 15 is a Chinese spring wheat landrace and it has exhibited adequate levels of APR to the prevalent Pst races in field environments for many years. In this study, a population of 177 recombinant inbred lines (RILs) was derived from Humai 15 × Mingxian 169. After screening based on a 90K chip array using 45 RILs and Kompetitive Allelic Specific PCR marker genotyping for the population of RILs, a major effect QTL in Humai 15 was located on the centromere of chromosome 2B, where it accounted for up to 47.2% of the phenotypic variation. Two other minor QTL genes from Humai 15 were located on chromosome arms 3BS and 4BL. The Yr18 gene was identified on chromosome arm 7DS in Mingxian 169.

Highlights

Stripe rust caused by Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst) is one of the most important foliar diseases of the winter wheat throughout the world
analysis of variance (ANOVA) detected significant phenotypic variation in Maximum disease severity (MDS) among the recombinant inbred lines (RILs) lines as well as the relative AUDPC (rAUDPC) for the F2 : 3 lines, environments, and line × environment interactions in the field experiments (Table 1). These results suggest that genes had large effects on the interaction between wheat and Puccinia striiformis f. sp. tritici (Pst) races in different environments
Humai 15 is susceptible to stripe rust in both the field and greenhouses in the seedling stage, whereas it is highly resistant to stripe rust in the field in the adult stage

Summary

Introduction

Stripe (yellow) rust caused by Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst) is one of the most important foliar diseases of the winter wheat throughout the world. This disease badly affects wheat production and can cause crop losses of up to 100%, the losses usually range from 10 to 70% (Chen, 2005). Resistance to stripe rust can be classified into all stage resistance (ASR) and adult plant resistance (APR) according to the growth stage. Plants with all stage resistance are highly resistant and readily handled by the breeder, and many ASR Yr genes are used in numerous elite varieties, they are prone to becoming susceptible when new pathogen races emerge. By contrast, pyramiding multiple QTLs into elite varieties can provide durable resistance to stripe rust, such as “Rely.” The phenotypes are difficult to assess for plants with APR genes and this can be a time- consuming process depending on the environment and adult stage, but molecular markers linked with QTLs can accelerate breeding program

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