Mining of Indian wheat germplasm collection for adult plant resistance to leaf rust.

Sundeep Kumar,Rakesh Singh,B S Phogat,Deep Shikha,V K Vikas,J P Jaiswal,Amit Kumar Singh,V A Solanki,Jyoti Kumari,M S Saharan,B K Honrao,Sherry Rachel Jacob,S S Vaish,P Jayaprakash,I K Kalappanavar,M Sivasamy,Gyanendra Singh ,Preeti Mishra ,Shivendra Singh ,Madhu Meeta ,Amit Kumar Sharma

doi:10.1371/journal.pone.0213468

Abstract

Leaf rust (Puccinia triticina Eriks.) is a fungal disease of wheat (Triticum spp.), which causes considerable yield loss. Adult plant resistance (APR) is one of the most sustainable approaches to control leaf rust. In this study, field-testing was carried out across ten different locations, followed by molecular screening, to detect the presence of APR genes, Lr34+, Lr46+, Lr67+ and Lr68 in Indian wheat germplasm. In field screening, 190 wheat accessions were selected from 6,319 accessions based on leaf tip necrosis (LTN), disease severity and the average coefficient of infection. Molecular screening revealed that 73% of the accessions possessed known APR genes either as single or as a combination of two or three genes. The occurrence of increased LTN intensity, decreased leaf rust severity and greater expression of APR genes were more in relatively cooler locations. In 52 lines, although the presence of the APR genes was not detected, it still displayed high levels of resistance. Furthermore, 49 accessions possessing either two or three APR genes were evaluated for stability across locations for grain yield. It emerged that eight accessions had wider adaptability. Resistance based on APR genes, in the background of high yielding cultivars, is expected to provide a high level of race non-specific resistance, which is durable.

Highlights

Wheat is one of the most important field crops in the world because it provides 20% of the total energy and protein in the human diet [1], playing a crucial role in global food security
Leaf rust caused by Puccinia triticina Eriks is deemed to be a major disease in almost all parts of the world where wheat is grown [5], and it causes significant yield loss
Based upon the initial screening, 190 promising lines were selected which were further confirmed in the second season/year for the presence of leaf tip necrosis (LTN) and leaf rust resistance under ten different locations, which falls under different wheat cultivating zones of India

Summary

Introduction

Wheat is one of the most important field crops in the world because it provides 20% of the total energy and protein in the human diet [1], playing a crucial role in global food security. Indian wheat germplasm with adult leaf rust resistance increase due to the ever-growing world population, which is expected to reach 9.7 billion by 2050 [3]. Leaf rust caused by Puccinia triticina Eriks Tritici) is deemed to be a major disease in almost all parts of the world where wheat is grown [5], and it causes significant yield loss. The extent of yield reduction depends on the stage of plant growth at which infection occurs, the degree of resistance of cultivars and disease severity, which, in turn, depends on weather conditions [7]

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Conclusion