Multiple patho-phenotyping and molecular analysis to characterize wide-spectrum durable leaf rust resistance in wheat...

Area of Science:

• Plant Pathology
• Agronomy
• Genetics

Background:

• Wheat leaf rust, caused by *Puccinia triticina* (*Pt*), is a major global threat to wheat production, necessitating effective resistance strategies.
• Cultivar resistance is crucial for managing wheat leaf rust, but pathogen evolution requires continuous identification of new resistance sources.

Purpose of the Study:

• To characterize leaf rust resistance (*Lr*) genes in Indian wheat genotypes.
• To assess adult plant resistance (APR) under field conditions and validate it using molecular markers.
• To identify valuable genetic resources for breeding wheat with enhanced resistance to evolving *Pt* pathotypes.

Main Methods:

• Evaluated 86 Indian wheat (*Triticum aestivum L.*) genotypes for seedling resistance against 14 *Pt* pathotypes.
• Conducted field evaluations over two consecutive rabi seasons to assess adult plant resistance (APR).
• Utilized molecular marker analysis to validate the presence of specific *Lr* genes.

Main Results:

• Identified nine key *Lr* genes (*Lr*1, *Lr*3, *Lr*10, *Lr*14a, *Lr*16, *Lr*23, *Lr*24, *Lr*26, and *Lr*34) in 26 genotypes.
• Detected quantitative, slow-rusting APR in over 64 genotypes, mediated by minor-effect genes.
• Confirmed the presence of *Lr*34 in 33 genotypes, *Lr*10 in 24, and *Lr*24 in 16 genotypes through molecular analysis.

Conclusions:

• Genotypes combining seedling and APR resistance, especially those with *Lr*34, *Lr*10, or *Lr*24, are valuable genetic resources for wheat breeding.
• Implementing multigenic resistance strategies is vital to combat pathogen evolution and ensure long-term wheat leaf rust management.
• The study highlights the importance of integrating diverse resistance genes to enhance wheat's resilience and contribute to sustainable agriculture.